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151 Cards in this Set
- Front
- Back
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The first line of immunologic defense is provided by ____. And includes the following 6 mechanisms.
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the innate immune system.
-anatomical barriers and secretions -phagocytes and phagocytosis -molecular sensors-PRRs -Inflammation -Fever -Others: cytokines, complement, clotting factors, & acute phase proteins |
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Primary immunologic Response
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part if innate response
2 types Humoral and Cell mediated Humoral -long lag phase (5-7 days) allows activated b cells to secrete Ab -Short duration (Ab titer detected for 10-17 days) Cell mediated -rejects grafts in 10-14 days. |
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Secondary immunologic response
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part of adapted response
cellular or humoral humoral -short lag phase (1-2 days)-memory cells -greater magnitude (high Ab titer) -longer duration (Ab titer detected for months) cellular -rejects graft within 4-8 days. |
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What Ig class develops first in primary response?
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IgM (all others through isotype switching)
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List types of APCs
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Professional
-macrophages -dendritic cells -b cells non professional -Fibroblasts (skin) -Thymic epithelial cells -Thyroid epithelial cells -Glial cells (brain) -Pancreatic beta cells -Vascular endothelial cells |
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Steps in phagocytosis
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1. bacterium attaches to phagocyte by evaginations due to pseudopodia around bacterial cell
2. bacterium injested due to pseudopodial engulfmant, making a phagosome 3. phago some fuses with lysosome forming a phagolysosome 4. lysosomal enzymes digest captured bacterium 5. digestion products released from phagocytic cell |
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Primary lymphoid organs
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Thymus and bone marrow
-where maturation of lymphocytes takes place |
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Thymus structure
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-bi lobed organ above the heart
-each lobe has 2 portions: outer crtex and inner medulla. -coretx has immature lymphocytes medulla has a few thymocytes |
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Thymus functions
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-immature lymphoid cells divide and migrate to medulla after entering through cortex. They then mature and leave the thymus
-Antigenic diversity of TCR generated here -Thymic selection |
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Thymic selection
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-lymphocytes learn to recognize foreign Ags and disregard self-Ags
-involves apoptosis of cells that are unable to recognize self MHC and have high affinity for self Ags associated with MHC. -95-99% of thymocytes die during maturation |
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Bone Marrow function
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-maintenance of B cells after development in liver during embryogenesis
-Not all mammals have bone marrow as primary lymphoid organ. Some have Peyer's patch in the wall of intestine. -Self reactive B cells eliminated here |
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Secondary lymphoid organs
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-diffuse collection of lymphocytes and macrophages or organized into lymphoid follicles.
-includes lymph nodes, spleen, and mucosal associated lymphoid tisue, cutaneous associated lymphoid tissue |
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Lymph node function
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-Activation of B cells
-conatins primary follices of follicular dendritic cell and small resting B cells, as well as secondary follices where activated B cells are active and proliferate and differentiate into plasma cells. |
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B cell activation
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1. Ags enter lymph node and trapped by interdigitating dendritic cells
2. These cells present Ag to Th cells in paracortex 3. a few Th and Bcells that are activated go to cortex and interact with primary follicle 4. There, the folicular dendritic cells, B cells and Th cells induce development of secondary follices 5. plasma cells differentiate in germinal centers and migrate to medulla where they leave the node |
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Spleen function
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-traps blood-borne Ags.
-old and defective RBCs destroyed in red pulp -B cell and Th cell activation and proliferation |
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Activation in spleen
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1. Ag enter spleen by splenic artery to marginal zone
2. Ag trapped by interdigitating dendritic cells and carried to PALS 3. In PALS interdigitating dendritic cells present Ag with MUCH class II molecules to Th cells 4. activated Th and B cells migrate to marginal zone to change primary follicle into secondary follicle 5. plasma B cells develop in secondary follicle |
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Mucosal Associated Lymphoid tissue basics
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mucous membrane lining digestive, respiratory or urogential system that contains organized lymphoid tissues (BALT, GALT)
-well organized -also peyer's patches, appendix and tonsils -barely organized-lamina propria in intestinal epithelium |
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M cells
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transport Ags from cavity of digestive, respiratory and urogenital tracts. have pockets in basolateral region of membrane that contains B cells, T cells and macrophages. Ags taken by endocytosis from lumen into pocket. They are located close to B cells tcells and macrophages
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cutanaeous associated lymphoid tissue
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Langerhans cells
-dendritic cells that after Agenic contact migrate to lymph nodes where they differentiate into interdigitating dendritic cells In ep |
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Structure of IgG
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comprise of two heavy chains and two light chains. Each light chains is boud to heavy chain by disulfide bond and by other non weaker interactions. The L-H linkages are identical. the first 100-110 aa's are the terminal variable regions (Vl and Vh). This si where the antigen binds and where the chain varies most.
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Fc/Fab/F(ab)2 fragment
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Fc- composed of only H chains, portion that binds to cells. created by papin.
Fab- composed of L and H chain, but not bound together, reated by papin Fab2-composed of two Fab like fragments, can bind and precipitate antigens-created by pepsin. |
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Isotype-definition
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1. an Antibody class which is determined by constant region sequence of heavy chain. There are five human isotypes (A, G, D, E, M)
2. one of the five major kinds of heavy chains in Ab molecules |
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allotype-definition
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set of allotypic determinant characteristic of some but not all members of a species. a specific type of Ig determined by your genes. You have a different allotype than your sister usually. differences inside of the species
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idotype
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set of antigentic determinant in variable domains of antibody or T cell receptor also called idiotypic derminant. generated by unique amino acid sequence for each antigen
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PRRs (pattern Recognition Receptors)
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receptors of innate immunity that recognize common structural motifs highly conserved i nmicrobial species
-present on macrophages, neutrophils, and dendritic cells. |
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follicular dendritic cells
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-live in lymph nodes
-do not originate in bone marrow. -do not express MHC II -has receptors for complement and Fc ends of Ab's |
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epitope
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-recognized by antigen binding site of Ab
-composed of hydrophilic amino acids on surface of immunogenic molecule -can be sequential or non-sequential amino acids -complex proteins have multiple overlapping B cell epitopes some of which are dominant |
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T cell antigen recognition
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-binding involves ternary complex, Antigen and Mhc molecule
-No binding of soluble antigens -MHC molecules required to display processed antigens -antigens mostly proteins, but some glycolipids and lipids on MHC like molec -epitopes are internal linear peptides produced by processing of Ag bound to MHC |
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B cell antigen recognition
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-involves binary complex of membrane Ig and Ag
-binds soluble antigens -does not require MHC -Ag's protein, polysaccharide or lipid -Epitopes are accessible, hydrophilic, mobile peptides that have sequential or non sequential peptides. |
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4 characteristic features of adaptive immunity
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SPECIFICITY- recognition of subtle differences among Ag's
DIVERSITY- capable of recognizing billions of uniquely different antigens MEMORY- second encounter with the same antigen produces a faster response SELF/NON-SELF RECOGNITION-distinguishes foreign from self Ag's |
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structure of Antigen binding site of Antibody
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consists of two variable regions-one of light chain and one of heavy chain.
-3 areas of variability in this segment are known has hybervariable regions or complementary determining regions (CDRs) -The rest of the variable domain shows less variation and are called framework regions |
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Portals of entry for microorganisms
which is worst? |
skin, mouth and upper alimentary canal, stomach, small intestine, large intestine, airway and lungs
skin is the worst portal of entry |
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Can you elicit an immune response by injecting only hapten? Give examples of haptens
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No, they must be covalently attached to carrier molecule to elicit response because they are too small
-aminobenzene, dinitrophenol and penicillin |
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haplotype definition
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set of alleles of linked genes present on one parental chromosome; commonly used in reference to MHC genes
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Which cell contains marker molecule CD3 and what does the marker do?
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Present on thymocytes, T cells and NKT cells
It has an essential role in TCR signal transduction and in cell surfacce expression of TCR |
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germinal center location and function
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region in lymph node and spleen where b cell activation proliferation and differentiation occurs. Sites of intense B cell somatic mutation and selection.
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cross reactivity definitions and examples
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Ability fo a particular antibody or T cell receptor to react with two or more antigens that posses a common epitope.
e.g.streptococcus pyogenes- expresses cell wall prtoeins called M antigens which would result in autoimmune reaction. Cause heart and kidney damage and streptococcal i nfections. also cowpox virus cross reacts with small pox (basis of Jenner's method of vaccination) |
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Which Ig is present in mucus secretions?
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IgA
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Which type of Ig has J chain?
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IgM and IgA
-required for polymerization -added just before secretion -part of secretory component in IgA -recepted y poly Ig receptor |
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What Ig has secretory componenet and what is its function?
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polypeptide chain derived from receptor responsible for transporting IgA across membranes
-produced by epithelial cells of mcouse membranes and has 5 Ig like domains that bind to Fc domains of IgA. |
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Which Igs contain hinge regions and which do not?
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IgG, IgD, IgA
small region between CH1 and CH2 domains rich in pro and cys giving flexibility |
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Fragments formed by pepsin digestion
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one fragment composed by two fab like fragments called Fab2
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Fragments formed by papain
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2 identical Fab fragments and one Fc fragment.
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Main effector function of IgM
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-activates complement
-receptor for antigen on B cells -agglutination in blood stream |
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How to d Th and Tc cells recognize antigen?
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they must be presented by MHC II and MHC I receptors, respectively by their T cell receptors
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adjuvant definition
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substances that are injected with antigen to enhance immune response by increasing the biological half life of the vaccine, inducing local inflammatory response and improving antigen dilivery and processing by APC
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avidity
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functional affinity of multivalent antigen binding to multivalent antibody molecules. Avidity strengthens binding to antigens with repeating identical epitopes. The more antigen-binding sites an individual antibody molecule has, the higher its avidity for antigen
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What type of chemical bond is involved in antigen antibody interactions?
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non covalent
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What is involved in I class switching?
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when stimulated by antigens the b cells switch heavy chains. Special sequences located upstream of each C gene are known as switch regionsAID is the key mediator of class switch recombination
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What is the mechanism/process involved in formation of membrane IgM and IgD?
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alternative splicing of the primary transcript
for IgM there is an exon 4 and then an S sequence at the 3' end (s for secreted) There are also M1 and M2 segments that encode transmembrane and intracytoplasmic domains. The gene can be poly adenylated at site one-3' end of exon4 or site 2 at 3' end of m2 exon. If splicing is at site one secreted form fproduced if at site 2 membrane found form produced. |
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What is affinity maturation?
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Antibodies with higher affinity to the antigen are preferentially selected to survive. Antibodies generated by somatic hypermutation
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Somatic hypermutation
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occurs only in germinal centers. mutations occur mostly in V regions to increase variation and specificity. usually nucelotide substitutions. repetitive regions called hot spots are more likely to experience variations
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Signal Joint
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In V(D)J rearrangement the sequence formed by the union of recombination signal sequences. The combination of codes that signalled for rearrangement, but does not code for protein
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coding joint
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The sequence at the point of union coding sequences during VDJ rearrangement to form rearranged antibody or Tcell receptor genes.
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Thymus dependent vs. thymus independent antigens
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Thymus dependent antigens require direct contact of B cells with Th in order to activate B cells. Either bacterial cell wal components (type one) that only do polyclonal activation or polymeric protein or capsular polysaccharides that do limited isotype switching.
Thymus independent antigens do not require physical contact between B and Th cells. does isotype switching, affinity maturation, immuno memory and polyclonal activation and is always a soluble protein |
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MHC Restriction
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requires self MHC protein to present peptide to T cells. requires mhc protein from own genome to present antigen in order to be recognized by T cells
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What types of peptides are present on a majority of class I nd class II mhc molecules
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self peptides
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Cytosolic pathway
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a process used to present endogenous antigens that degrades proteins to constituent amino acids or inserted into the ER by TAP and changed into a peptide class I mhc complex.
in the ER: -MHC I alpha and calnexin bind -B2 microglobulin causes calnexin to disassociate and it binds. -ERp57, tapasin and calreticulin bind to b2 and alpha chain. -peptide is added causing tapasin, calreticulin and ERp57. |
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Endocytic pathway
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used for exogenous antigens.
-antigen enters clatherin coated visicle which then is invaginated and eventualy becomes a late endosome of only antigens -class II mHC from golgi comoplex combine with antigenand then is presented on cell membrane. -when MHC II leaves golgi it has invariant chain protein on it which is then digested down to CLIP which is a place saver for the antigen -the antigen replaces CLIP and is presented. |
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What is the outcome in immune response terms if a species has limited MHC polymorphism?
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they will be more susceptible to disease because their genetic code has limited variability which results in limited Ig variability. This results in antigens not being able to be recognized.
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positive selection eliminates what kind of cells
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eliminates T cells that don't recognize self MHC, or do not bind intermediately with them.
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B7 molecules are expressed on what kinds of cells? what receptors on T cells interact with them and what is the result of the interaction?
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They are present on APCs and interact with CD28 on resting and activated T cells
the binding of B7 and CD28 results in T cell activation. |
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What is the result (interms of receptor expression and cytokine release) of activated Th cdells receiving signals 1 and 2?
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Full T-cell activation.
-IL-2 is secreted and IL-2 receptor is created |
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what happens when t cells don't get signal 2?
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they become anergic and cannot respond to peptide MHC complex.
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What are the necessary steps involved in T cell dependent B cell activation?
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-B cell receptor = mIg + Igalpha/Igbeta heterodimers
-Signal transduces to Igalpha/beta -ITAM is activated -antigen crosslinks mIg (signal 1) -CD40 on B cell reacts with CD40L on Th cell. -TCR recognizes peptide MHC -CD28 on active Th interacts with B7 on b cell -CD40L Th interacts with C40 on B cell -Th secretes cytokines that suport B cell proliferation |
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What class of surface Ig is present on Naiive b cells?
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IgM
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5 attributes of cytokines
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pleiotropy
redundancy synergism antagonism cascade induction |
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What is bacterial septic shock?
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occurs a few hours after infection by gram negative bacteria
-blood pressure drops, fever, diarrhea, widespread blood clotting -endotoxins on bacterial cell wall bind to TLRs on dendritic cells and macrophages -secrete IL-1 and TNF alpha |
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What is bacterial toxic shock?
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caused by aa superantigen
-toxic shock syndrome toxin from Staphilococcus aureus -large amount of T cells activated-->excessive cytokine production -lots of TNF alpha and IL-1 -induces widespread blood clotiting, fever, and shock |
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superantigen
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toxins produced by microorganisms that bind both to MHC II and to Vb domain of T cell recepter annd thereby activating all T cells with a specific Vb domain.
-activate lots of T cells regardless of Agenic specificity (e.g. TSST) |
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Cytokines in lepromatous leprosy
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Th1 produces:IL-2, a little IFN gamma, TNF beta
Th2 produces a little IL-4 |
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cytokines in tuberculoid leprosy
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Th1 produces a little TNF beta
Th2 produces IL-4, IL-5, IL-10 |
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Subunits of IL-2 receptor
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heterotrimeric protein made of alpha, beta and gamma subunits
-resting t cell has beta & gamma chains -activated t cell expreses apha, beta and gamma chains |
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Which cells are IL-2 receptors on?
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NK cells, resting T cels as well as activated T cells and activated B cells
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What determines the differentiation of antigen primed Th cells into Th1 and Th2 cells?
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by cytokines
-IL-12 turns helper cells into Th1 -If environtment is dominated by IL-4 Th2 cells develop |
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Function of T helper 1 cell
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-produces IFN-gamma, IL-2 and TNF beta
-it controls DTH, macrophage activation and certain opsonic or complement fixing IgGs |
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Function of T helper 2 cell
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-produces IL-4, IL-5, IL-10, and IL-13
-it thereby induces eosinophil activation and IgE and some other Ab classes |
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Major reactants in the three complement pathways
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Classical - Ab/Ag complexes
Alternative - innate immune system components Lectin-mannose binding lectin (MBL) |
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Componenets in initial phases of each complement pathways
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classical-C1
Alternative-C3 Lectin- C3 convertase |
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components involved in membrane attack complex
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C5->C5b
C5b6 C5b67 C5b678 C5b6789 |
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Components involved in initiation of alternative pathway
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C3->C3b
C3b + factor B Factor b becomes substrate for factor D gives us Bb and Ba fragments. C3bBb is attached and Ba diffuses C3bBb can convert C3 intomore C3b to form C3bBbC4b This molecule acts as C5 convertase gives us C5a and C5b C5b used in MAC complex |
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How are immune complexes cleared?
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Through component
-Need to be coated with C3b -RBCs have CR1 that interact w/ C3b coated immune complexes and carry them to liver and spleen where they're destroyed. |
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Components in C3 convertase in classical pathway
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C4b2a
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Components in C5 convertase in classical pathway
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C4b2a3b
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Direct and Indirect Coomb's test
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Direct-detects Abs on erythrocytes
-anti globulin binds to human Abs bound to RBC-->crosslinking of RBC-->agglutination indirect--detects anti erythrocyte antibodies in serum -add serum to target RBC's, then add coombs reagent--> agglutination |
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Pan B cell marker
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CD 19, CD 20, CD22, CD79a, CD79b, L26, PAX-5
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Pan T cell marker
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CD2, CD3, CD7
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Steps in neutrophil extravasion
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1. Rolling- through low affinity selectin bond
2. Activation-chemoattractant stimulous 3. Arrest/adhesion- mediated by integrins binded to Ig family 4. Trans endothelial migration-through pecam |
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What are High Endothelial Venules? (HEV)
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specialized cells with cuboidal shape form a region in secondary lymphoid organs except for spleen
-they are postcapillary -have lots of adhesion molecules to allow for extravasation |
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First cell type to extravasate in inflammation
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neutrophils
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Which cell types is first to extravasate in type IV hypersensitivity reactions
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monocytes
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What are the 3 inflammatory cytokines?
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TNF-alpha, IL-1, INF-gamma,
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what causes acute inflammation and what are the symptoms?
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It's caused by tissue injury that causes increases vasodilation. increased vascular permeability means fluid builds up
-involves fever, leukocytosis, increased synthesis of ACTH and hyrdocortisone and production of acute phase proteins by liver (CRP) |
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How do CTL kill target cells?
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2 ways
-delivery of cytotoxic proteins that are released from CTLs and enter target cells -perforin forms pore and granzyme B causes capsase-3 to induce apoptosis -interaction of membrane bound Fas ligand on CTLs with the Fas receptor on the surface of target cells -induces caspase 3 to form to induce apoptosis |
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What is the major protective mechansim attributed to NK cells?
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-perform nonspecific cytotoxic activities
-release perforins and granzymes to induce apoptosis |
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How do NK cells develop?
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they're lymphoid cells that share progenitor w/ t cells
-do not mature exclusively in thymus and do not go antigen receptor gene rearrangement |
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What characteristics are unique to NK cells?
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-have CD2, b subunit if IL-2 and CD16
-cytokines produced have part of both innate and adaptive immunity -have Activating receptor that engages ligand on target cell |
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What mechansims do NK cells use to recognize target cells?
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If cell recognizes both the cytotoxic ligand through it's activating receptor and the class I mhc through its inhibitory receptor, then no killing ocurs.
If cell recognizes ligand through activating receptor but no class I MHC in it's inhibitory receptor, the cell will then recognize it as ok to kill. |
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What mechanisms do NK cells use to kill the target cells?
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They, like CTLs have FasL on their surface. They also have lots of granules containing perforin and granzymes.
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What is ADCC?
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Cells recognize Antibodies bound to target cells by binding to the Fc regions with their Fc receptors
-involves different mechansims but not complement mediated lysis -lytic enzymes released at Fc receptor -NK & Macrophage release TNF -eosinophil andNK release perforin |
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ADCC participating cells
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neutrophil, NK, eosinophil and macrophage
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examples of four types of hypersensitivity
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Type I- pollen allergy
Type II- erythroblsatosis fetalis type III- serum sickness, rheumatoid arthritis type IV- contact dermatitis, TB, and graft rejection |
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What happens when Fc epsilon receptors are cross linked?
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Mast cells and basophils become activated. activate PTK and degranulate starting hypersensitivity type I reaction
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What types of transplant rejection occurs in HLA mismatch and in blood group mismatch?
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Mismatched HLA-->acute rejection
blood antibodies->hyperacute rejection |
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Purpose of antinuclear antibody test
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diagnoses SLE
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Graft versus leukemia effect
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Transplanted T lymphocytes not only may attack the recipient's normal tissues (graft versus host) but may recognize and attack the malignant cells in the recipient. This effect was noted when 1) leukemia recurrence after transplant was seen to be more likely if the donor and recipient were identical twins than if they were non-identical siblings, 2) the more prominent the graft versus host disease the less likely was leukemia recurrence, and 3) the removal of donor T lymphocytes decreased graft versus host disease but also resulted in a higher frequency of leukemia relapse. Each of these observations could best be explained by an immune attack
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graft versus tumor effect
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similar to graft versus leukemia effect, but instead of attacking rogue leukocytes it attacks the tomor that is forming
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Minor histocompatibility Ag's
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proteins or other molecules that are outside the MHC region that cause graft rejection
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How do you suppress/prevent graft rejection?
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1. mitotic inhibitors
2. corticosteroids 3. total lymphoid irradiation 4. immunosuppressive agents. |
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How can GVHD be minimized?
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-match the HLA
-transplant cord blood for T cells and not thymus -T cell depleted bone marrow transplant |
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CD markers on T reg cells
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CD4 and CD25
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How does influenza virus untergo antigenic shift?
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shuffles RNA strands within host cell infected two or more viral strains (in order to increase variability)
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How do HIV and influenza virus evade immune response?
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they use antigenic variation- the ability to frequently change their surface antigens.
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How to trypanosomes evade immune response?
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changes coat antigen (variant surface protein). There are 100 VSG genes clustered in multiple chromosome sites
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Passive immunization examples
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maternal transfer of preformed Abs against diptheria, Tetanus, strep, rubeola
inidviduals who have not received tetanus vaccine are given antibody produced in horses agains the toxin passive administration of Abs again poisionous snake bites or insect bites |
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Types of Vaccinations and examples
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Live attenuated-TB, polio, FluMist
Subunit vaccines-diptheria and tetanus inactivated vaccines-Salk polio Conjugate vaccines- Hib vaccines, tetanus toxoid DNA vaccines-? experimentally bird flue and west nile |
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cause of SCID
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genetic defect in which adaptive immune responses do not occur because of Not T and possibly no B and NK cells
Thought to be caused by deficieny of common gamma chain of IL-2R. |
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Why is it difficult to treat HIV?
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RNA contained in the virus into DNA, the genetic information code contained in the human body. This DNA becomes a part of the human host cell. The fact that viruses become part of the human body makes them difficult to treat or eliminate without harming the patient.
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What are the virally encoded enzymes necessary for HIV infection?
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integrase and protease
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What is a malignant tumor?
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grow uncontrollably and invade other tissues and organs
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What are teh agents responsible for cancer formation?
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Chemical-DNA alkylating
Physical-UV/ionizing radiation Viruses- HPV, HBV, EBV Oncogenes-can signal anti apoptosis, antiproliferation, proliferation or control of proliferation |
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What virus causes cervical cancer?
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the human papiloma virus
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What are tumor specific and tumor associated antigen and how do they originiate?
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Tumor specific-tumor rejection antigens, occur only in tumor cells, result in tumor cells that generate altered cellular proteins, they are presented to T cells and then they become the target of tumor specific T cell response because they're not on normal T cells. Can be induced by carcinogen, virus,
Tumor associated- more comon and found on tumor and normal cells in fetal life, after birth only on a few organs or at lower concentrations. Immune responses can be supressed because they're considered self antigens |
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What are the methods used for Ig and TCR rearrangements?
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Ig- combinatorial VJ and VDJ joining, juctional flexibility, N additon, P addition, somatic mutation and combinatorial association of chains
TCR combinatorial VJ and VDJ joining, alternative joining of D gene segments, juntional flexibility, N addition, p addition, combinatorial assn of chains (NO SOMATIC MUTATION) |
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How is HLA typing performed?
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Through microcytotoxicity tests. cells from the donor are added to wells and then exposed to Anti HLA molecules for different alleles. If the cell lyses, the cells will take up the dye and be stained.
Also use RIST & RAST. |
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Rhogam
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used to prevent Anti Rh Abs of mother from attacking Rh Ab'ed cells of baby.
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VDJ recombination
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VDJ recombinase
RAG1 and RAG2 TdT |
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primary immunodeficiency
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part of the body's immune system is missing or does not function properly
e.g. Omenn syndrome-mutations in RAG1 and RAG2 (type of SCID) SCID- (includes x-linked combined immunodeficiency-common gamma chain) B and T cell defect DiGeorge's syndrome-thymic aplasia chronic granulomatous disease-lacks phagocycyte NADPH oxidase |
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Inflammatory marker used to indicate atherogenesis synthesized in liver
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C reactive protein
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Why do mouse monoclonal antibodies need to be humanized? name two methods by which mouse monolonal antibodies are humanized.
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because if they're not fully humanized they can cause serum sickness or other disorders like HAMA
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What types of cancer that are best diagnosed by DNA microarrary?
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acute myeloid leukemia
acute lymphoid leukemia |
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What types of cells have CD32?`
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monocyte, macrophages, langerhans cells, neutrophils, B cells, and platelets
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CD2 location and role
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T cells, thymocytes, NK cells
adhesion molecule involved in Tcell activation |
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CD3 location and role
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thymocytes, T cells, NKT cells
role in TCR transduction and in cell surface expression of TCR |
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CD4 location and role
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MHC class II restricted T cells, some thymocytes, monocytes/macrophages, granulocytes
coreceptor for class II T cell activation, thymic differentiation marker for T cells; receptor for HIV |
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CD5 placement or function
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mature t cells, early thymocytes; small amounts on a subset of mature B cells
positive or negative modulation of TCR and BCR signaling, depending on the type and developmental stage of cell displaying it. |
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CD19 placement or function
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follicular dendritic cells, B cells from earliest recognizable B lineage cells during development to B cell blasts but lost on maturtion to plasma cells
part of B cell coreceptor with CD21 and CD81; a critical signal tranduction molec that regulates b cell development, activation, and differentiation |
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CD20 placement or function
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B cells
ligation activates tyrosinekinase dependent pathways and may have a role in B-cell proliferation and differentiation; regulates B lymphocyte activation and proliferation vi regulation of transmembrane Ca2+ channel subunit and cell cycle progression |
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CD25 placement or function
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activated B cells, T cells, monocytes and oligodendrocytes, some thymocytes, macrophages, NK cells, myeloid cells and a subset of dendritic cells
Low affinity IL-2 receptor and is an activation marker; induces activtion and proliferation of T cells, thymocytes, NK cells, B cells, and macrophages; also plays a role in T cell mediated immune response. Associates with beta and gamma chains to form high affinity with IL-2R |
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CD28 placement or function
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Mature CD3+ thymocytes, most peripheral T cells, plasma cells
co-stimulation of T cell proliferation and cytokine production upon binding CD80 or CD86 |
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CD45 placement or function
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all hematopoietic cells except erythrocytes; especially high on lymphocytes; different isoforms characteristic of differentiated subsets of various hmeatopoietic cells
regulates a variety of cellular processes, including cell growth, differentiation, mitotic cycle, and oncogenic transformation; essential role in T and B cell antigen receptor mediated activation; possible role in receptor mediated activation in other leukocytes. |
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CD16a placement or function
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transmembrane form in humans on NK cells, macrophages, and mast cells; GPI anchored form expressed on neutrophils; in mice, no GPI anchored form of CD16a has been identified and the transmembrane form is expressed on macrophages, NK cells, neutrophils, myeloid precursors, and the majority of early CD4 CD8 TCR fetal thymocytes
subunit of low affinity Fc receptor, involved in phagocytosis of antibody complexed antigen and in ADCC |
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CD56 placement and function
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Human NK cells, subset of CD4 and CD8 cells, also brain in crebellum and cortex and neruomuscular junctions
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CD40 placement and function
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All mature B cell lineages except plasma cells, macrophages, follicular dendritic cells, activated monocytes endothelial cells, fibroblasts, interdigitating dndritic cells, keratinocytes, cd 34 hematopoietic cell progenitors
binds to CD154. roles in B cell growth, diff, isotype swithcing; apoptosis rescue signal for germinal center b cell; stimulation of cytokine production in macrophages and dendritic cells; upregulation of adhesion molecules on dendritic cells. Plays a critical role in regulation of cell mediated immunity as well as antibody mediated immunity |
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CTLA4 placement and function
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on helper t cells
transmits inhibitory signal to t cells |
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Based on Ig gene rearrangement of heavy and light chain genes, how would you classify whether a cell is preB cell or a B cell?
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preB YOU DON'T KNOW THE ANSWER
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Quadrants of FACS and what they indicate/what cell types are there?
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top left hand-single positive PI (CD8)
bottom left hand side-double negative cells- thymic cells Top right hand-double positive poluation (both CD4 and CD8) Bottom right-single positive FITC(CD4) |
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FACS and Leukocyte adhesion deficiency
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most marks in top left hand corner indicating LFA-1 deficiency- prone to bacterial infections
CD18 vs. CD3 |
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X-linked agammaglobulinemia and FACS
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cd3 vs. cd19
cells on bottom of chart indicating low CD19 (no b cell receptor function) |
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Bone marrow is often depleted of T cells before transplantation in order to prevent GVHD. However in the treatment of leukemia by BM transplantation Tcells in the graft can have beneficial effects. How do you explain this result?
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Leukemia can be eliminated by the T cells who recognize the cells as foreign
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Explain one mechanism by which cancer and viruses escape from immune surveillence
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viruses- antigenic drift is the gradual accumulation of point mutations leading to minor changes in the surface
HIV and cancer use antigenic variation- the ability to frequently change their surface antigens. |
