Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
86 Cards in this Set
- Front
- Back
protection, innocuous substance, inury, and immunologic tolerance come about because of....
|
Recognition of foreign substances
|
|
2 functions of immune system
|
recognition of foreign substances and surveillance
|
|
vaccination
|
innoculated material is not virulent human pathogen
|
|
Cellular Theory of Immunity
|
Metchinoff; dependent on phagocytic cells
|
|
Humoral THeory of Immunity
|
Erhlich; dependent on substances in the cell-free portion of the blood
|
|
4 charac of innate immunity
|
constitutive, rapid, nonspecific, lack of memory
|
|
innate: external defenses
|
- prevent penetration
1. intact skin/mucous membranes; tears 2. respiratory tract 3. alimentaty tract 4. urogenital tract 5. normal intestinal flora |
|
innate: internal defenses
|
- once a pathogen has entered
1. chemical barrier (incr in temp that drives malaise) 2. natural killer cells (dont need Ag exposure) 3. interferon (cytokines) (alpha and beta; dont let replication happen) 4. alternative complement pathway 5. detection of pathogens 6. phagocytes 7. inflammation |
|
PAMPS (pathogen-associated molecular pattern) / pattern recognition sequence
|
biologic patterns unique to and needed for the survival of microorgs but arent found on mammalian cells
-encoded into DNA -body can recognize anything that displays these patterns |
|
pattern-recognition receptors
|
recognize PAMPS;
-scavenger, LPS, nucelotide-bind oligomerization domian (NOD), TLRs |
|
T cells need what to become activated:
|
1. binding of foreign antigens
2. binding of costimulators (expressed on innate immune system cells with PAMPS) |
|
inflammation
|
increases vasoldillation,
increases capillary permeability, increases cytokine production, increases influx of cells with more phagocytosis, which leads to Acute Phase Response |
|
innate immunity binds what to what?
|
peptidoglycan binds to TLR2
|
|
adaptive immunity - basic
|
-surveillance mech.
-recognizes foreign substances (Ag) -selectively eliminates them - leukocytes - |
|
charac of adaptive
|
1. inducible - needs to be turned on
2.specific - clonal selection 3. memory - effector and central memory cells 4. diversity 5. knows self from nonself 6. self-limiting |
|
effector memory cells
|
secrete or migrate to inflamed peripheral tisses and display immediate effector function
|
|
central memory cells
|
stored in lymphnodes/spleen for memory
|
|
humoral immunity
|
mediated by serum proteins = antibodies
-protection against extracellular bacteria, exotoxins, and viruses - derived from daughter B cells = plasma cells |
|
cell-mediated immunity (CMI)
|
mediated by thymus-derived lymphs (Tcells)
-protection against viruses in intracellular phase, tumor cells - imp in organ transplant rejection |
|
first 2 steps of response
|
1. antigen recognition
-cognitive= touching, interacting with Ag -activation 2. Ag elimination - effector phase= lymphocyte proliferation and differentiation/synthesis of new proteins and memory cells |
|
selective theories of antibody formation
|
cells that possess receptors for an antigen preexist before exposure to that Ag. it selects cells with the right receptors and causes their proliferation/differ.
|
|
side-chain hypothesis
|
a pop of cells existed with side-chains on the surface (antibodies). when Ag enters, it combines with side-chain. side-chain complex gets released, and the original side-chains are replaced
|
|
instructive theories
|
Ags act as a template around which antibodies are formed
WRONG |
|
watson and crick
|
dna structure
|
|
clonal selection theory
|
Burnet- develop lots ot B-cell precursors in early development. each one is only for ONE Ag. stocks are taken of self-Ag, forbidden clones are destroyed. clonal expansion occurs
|
|
NK Cells
|
cytotoxic cell of innate immunity
-react to any target, tumor cell or viral cell |
|
Dendritic cells (DCs)
|
controller cells of immune system
-myeloid derived, found in all tissues |
|
cells involved in inflammatory response
|
monocytes
-neutrophils -eosinphils -basophils and mast cells |
|
why do stem cells proliferate?
|
1. to renew itself
2. to give rise to new progeny that can differentiate into specialized cells |
|
what are the 2 ways that stem cells can differentiate?
|
1. lymphoid pathway
2. myeloid |
|
5 cells involved in immune response
|
1. T cells
2. B cells 3. phagocytic/Macrophages 4. NK cells 5. dendritic cells |
|
lymphocytes
|
have receptors to bind Ag
-B-immunoglobulins = humoral -T-TCRs=CMI |
|
B lymphocytes
|
-only cells in body that can differentiate into plasma cells that produce antibodies
-responsible for humoral immun -need help from Th to make antib's -Ag specific -glycoproteins -immunoglobs (ab's)=receptors Ag -Membrane Ig = Ag-speci receptor -mature b cells = IgM, IgD - express Fc and C receptors -APC= Ag presenting cells -MCH I and II |
|
T lymphocytes
|
-from Tcell committed stem cells in bone marrow
- mature in thymus -TCR specificity is set at double negative stage -cant express cd3 and cd4 or cd8 at the same time - most Th=cd4, Tc=cd8 |
|
Th - helper T cells
|
initiate and enhance an immune response
|
|
Tc - Cytotoxic T cells
|
cells that destroy foreign allografts, cancer cells, and virally infected cells
|
|
T cell functions
|
1. delayed-type hypersensitivity
2. graft-vs-host reaction 3. allograft rejection 4. immunity against tumors 5. immunity against viral infections 6. contact sensitivity 7. immunity against intracellular pathogenic parasites 8. control immune responses |
|
Macrophages
|
1. mononuclear cells
2. possess peroxidase and esterase activity 3.have specific surface receptors for antibody 4. exhibit phagocytic pinocytic abilities 5. can be stimulated into a state of activation 6. possess a caried and prlific secretory ability -not clonally restricted or ag-specific |
|
Dendritic Cells
|
-possess and present Ag to Th
-can induce primary immuno response -immatures= highly phagocytic -mature=no phago and no Ag interaction -migrate to lymph or bloodand become mature, where they present the Ag to Th -come from hematopoietic cells - control 3 Rs - repetoire, recognition, response |
|
circulating dendritic cells
|
in blood and lymph
|
|
interdigitating dendritic cells
|
in T-cell areas of 2ary lymphoid tissue then medulla
|
|
interstitial dendritic cells
|
more organs
|
|
langerhans; cells
|
in epidermis and mucous membrane
-interstitial |
|
follicular dendritic cell
|
in B-cell rich follicles of lymph nodes
-dont act as APCs -low levels of membrane receptors |
|
NK cells
|
-mediators of innate immunity
-discriminate between self and nonself -large granular lymphocytes -Fc receptor bearing cytotoxic cells -NOT MHC restricted -can secrete cytokines -dont express antibody receptors or TCRs |
|
primary lymphoid organs
|
1. bone marrow
2. thymus |
|
bone marrow
|
- source of all immune cells
- site of B-cell development in adults - reticular tissue and blood vessels |
|
thymus
|
-development of T cells
-important organ in immunogenesis -bilobed, encapsulated - cells move from cortex to medulla |
|
secondary lymphoid organs
|
1. lymph nodes
2. spleen |
|
lymph nodes
|
2 functions: filtration and recirculation of ag-stimulated lymphocytes
3 regions: - outer cortex: B-cell nodules called follicles - paracortex: T-cell area - medulla: B cells, plasma cells, reticular cells, dendritic, and macrophages |
|
spleen
|
-collects dead or dying cells
- removes worn-out red blood cells -filters antigen from blood -generation of mainly humoral immunity to foreign Ags |
|
where do lymphoid cells come from?
|
common ancestor called the pluripotent hematopoietic stem cell
|
|
what does the stem cell differentiate into?
|
actively metabolizing progenitor cell
|
|
Hematopoietic Pathways
|
-origin of immune cells
-Ag-independent activity |
|
common myeloid progenitor cell
|
leads to non-specific cells (interstitial cells, monocytes, macrophages, etc)
|
|
common lymphoid progenitor
|
can lead to specific or non-specific
leads to T cells and B cells |
|
can T cells bind directly to their TCR?
|
no, they must first be cut into peptides and processed and bound to (presented on) MHC molecules
|
|
who do macrophages and dendritic cells present antigen to?
|
T-cells, NOT b-cells
|
|
germinal center
|
where final steps of maturation occur in lymph node
|
|
primary follicle
|
cells that react with Ag undergo proliferation and differentiation here
|
|
antigens def
|
substances that when introduced into verts induce the formation of antibodies that react specifically with them.
most common = proteins |
|
immunogenicity
|
ability of a substance to induce or elicit humoral or cell mediated immunity.
|
|
antigenicity
|
the ability of a substance to react or bind with the specific antibodies it induces
|
|
*** is an immunogen an antigen and/or an antigen an immunogen?
|
an immunogen is an Ag, but not the other way around
|
|
antigens - charact
|
1. large molecular size
2. chemical complexity 3. degradability 4. foreignness |
|
antigenic determinants/epitopes
|
immunologically active portions of the antigen molecule
- reactive sites of an antigen -come in direct contact with combining sites of Abs |
|
haptens
|
-not immunogenic in themselves
-can react with preformed antibodies of the proper specificity -gain adaptive immunity by coupling haptens with a carrier molecule -chemicals that are functionally equivalent to anitgenic determinants |
|
how are haptens recognized?
|
their chemical structure
- the Ab reacts with homologous hapten - nature of chemical group - electrical charge -shape (position, size, stereoisomers) |
|
where are the Ag determinants of a macromolecule?
|
at its surface.
- they induce adaptive immunityand the Abs react with them |
|
epitopes of myoglobin
|
sequential/continuous: linear, size, surface, and unique
-minority of epitopes recognized by antibody but the MAJOR epitopes recognized by T cells |
|
epitopes of hen egg white lysozyme
|
discontinuous/nonsequential: conformational or assembled topographic
- bcells |
|
where are epitopes located?
|
in flexible regions of immunogen
|
|
antibody - definition
|
glycoproteins found in the serum and other body fluids of verts that react specifically with the Ag that induced their formation
-family of immunoglobulins |
|
family of antibody?
|
Ig superfamily
|
|
pathogenic Igs (myeloma proteins)
|
characteristic structure of Abs but come from a disease state instead of a challenge with an immunogen
|
|
Ig structure
|
1. versatility in Ag binding
2. Ab specificity 3. Ab effector functions |
|
What type of globulins are Abs?
|
Gamme-globulins
|
|
Gamma-globulins
|
any molecule that migrates in the gamma-glob peak on electrophoresis. includes most antibodies.
|
|
immunoglobulins
|
family of molecules with similar structures and physical properties. have homologous aa's and similar domain structures and quaternary structures
|
|
antibody
|
molecule in the Ig family.
-has binding specificity for a particular Ag. -All Abs are Igs, not all Abs are gammas |
|
Fab fragments
|
fragments bind antigenic dexterminants = antigenic binding (ab)
- dont show precip or agglutination and will not fix complement |
|
Fc fragments
|
fragments dont combine with Ag and crystallize upon cold storage
|
|
F(ab')2
|
large fragment that contains both ag-binding sites of IgG and can also be treated with reducing agents to yield 2 Fab-like fragments
|
|
V region
|
composed of hypervariable (complementarity-determining regions CDRs) separated by less variable regions called framework regions
-CDRs contain aa's that line the Ag-binding cleft of the Ab molecule |
|
CL
|
disulfide bond, Bstrands
|
|
VL
|
CDR, NH2
|