Reading...
Play button
Play button
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;
97 Cards in this Set
- Front
- Back
|
cold agglutinin
|
- aka cryoagglutinin
- an IgM antibody - produced by 60% of patients infected with Mycoplasma pneumoniae - reversibly agglutinates human erythrocyte antigen I positive RBCs at low temperatures - cause of cold agglutinin disease (autoimmune hemolytic anemia) |
|
|
DiGeorge syndrome
|
- impaired thymic development (affects T-cells)
- small deletions in chromosome 22 - also spontaneous |
|
|
Chronic granulomatous disease
|
- X-linked ressive or
- autosomal recessive - NADPH oxidase defficiency in neutrophils |
|
|
Follicle of Lymph Node
|
- Site of B-cell localization and proliferation.
- located in outer cortex of node - primary follicles are dense/dormant - secondary follicles have pale central germinal centers, active. |
|
|
Medulla of Lymph node
|
- cords -> closely packed lomphocytes and plasma cells
- sinuses -> reticular cells and macrophages - communicate with efferent lymphatics |
|
|
Paracortex
|
- Houses T cells.
- between follicles and medulla - contains high endothelial venules -> allow T and B cells to enter from blood - enlarged in extreme cellular immune response - undeveloped in DiGeorge syndrome |
|
|
Location of T-cells in Spleen
|
- Periarterial lymphatic sheath
- red pulp |
|
|
Location of B-cells in spleen
|
- follicles within the white pulp
|
|
|
Sinusoids of spleen
|
- long vascular channels in red pulp
- fenestrated "barrel hoop" basement membrane - Machrophages found nearby |
|
|
Thymus develops from what?
|
- 3rd Branchial pouches
- Lymphocytes originate from mesenchyme |
|
|
Hassall's corpuscles
|
- found in medulla of thymus
- formed from type VI epithelial reticular cells - source of cytokine TSLP (unknown function) |
|
|
Components of innate immunity
|
- neutrophils
- macrophages - dendritic cells - complement |
|
|
Components of Adaptive immunity
|
- T cells
- B cells - circulating antibody |
|
|
Differentiation of T cells
|
- T cell precursor from bone marrow
- in thymus, aquires T cell receptor, CD8 and CD4 (becomes CD4+ and CD8+) - One cluster of differentiation becomes dominant - in lymph node, CD4+ become cytotoxic T cells - CD8+ become T helper cells (1 and 2) |
|
|
Th1 cells
|
- produce IL-2 and IFN-gamma
- activate macrophages and cytotoxic CD8+ T cells. |
|
|
Th2 cells
|
- produce IL-2, IL4 and IL-5
- help B cells make antibody |
|
|
MHC I
|
- encoded by Human Leukocyte Antigen (HLA) A, B and C
- expressed on almost all nucleated cells - antigen loaded in RER - mediates viral immunity - pairs with beta 2- microglobulin |
|
|
MHC II
|
- encoded by Human Leukocyte Antigen (HLA) DR, DP and DQ
- expressed only on antigen presenting cells (APCs) - antigen loaded in an acidified endosome - main determinants of organ rejection |
|
|
B cells
|
- make antibody
- IgG antibodies opsonize bacteria and viruses - IgE responsible for Allergy from type I hypersensitivity - Antibodies cause organ rejection (fast) |
|
|
T cells
|
- CD4+ T cells help B cells make antibody and produce gamma-interferon that activates macrophages
- kills virus-infected cells directly (CD8+ T cells) - produces allergy through type IV hypersensitivity - organ rejection (slow) |
|
|
Antigen-presenting cells
|
- Macrophages
- B cells - Dendritic cells |
|
|
Th activation
|
- Foreign body is phagocytosed by APC
- Foreign antigen is presented on MHC II and recognized by TCR on Th cell (first signal) - Costimulatory signal given by B7 of APC binding with CD28 of Th - Th cell activated -> produces cytokines |
|
|
Tc activation
|
- Endogenously synthesized (viral or self) proteins presented on MHC I
- recognized by TCR on Tc cell (signal one) - IL-2 from Th cell activates Tc cell to kill virus-infected cell (signal 2) |
|
|
Antibody structure
|
- VL and VH chains recognize antigens
- CH of IgM and IgG fixes complement - Heavy chain contributes to Fc and Fab fractions - Light chain contributes only to Fab fraction |
|
|
Antibody diversity generaged by:
|
- random recombination of VJ (light chain) and VDJ (heavy-chain) genes
- random combination of heavy chains with light chains - somatic hypermutation - Addition of nucleotides to DNA during genetic recombination by terminal deoxynucleotidyl transferase |
|
|
Mature B lymphocytes express what?
|
- IgM and IgD
|
|
|
Isotype switching
|
- mediated by cytokines and CD40 ligand
- causes mature B lymphocytes to differentiate into plasma cells that secrete IgA, IgE or IgG |
|
|
IgG
|
- Main antibody in secondary response
- most abundant - fixes complement - crosses the placenta - opsonizes bacteria - neutralizes bacterial toxins and viruses |
|
|
IgA
|
- Prevents attachment of bacteria and viruses to mucous membranes
- does not fix complement - monomer or dimer - found in secretions - picks up secretory component from epithelial cells before secretion |
|
|
IgM
|
- Produced in the primary response to antigen
- fixes complement - does not cross the placenta - antigen receptor on the surface of B cells - monomer or pentamer |
|
|
IgD
|
- Unclear function
- found on surface of B cells and in serum |
|
|
IgE
|
- Mediates immediate (type I) hypersensitivity by inducing the release of mediators from mast cells and basophils when exposed to allergen
- mediates immunity to worms - lowest concentration in serum |
|
|
Ig allotype
|
- Ig epitope that differs among members of same species
- on light or heavy chain |
|
|
Ig Isotype
|
- Ig epitope common to a single class of Ig
- determined by heavy chain (IgG, IgA, etc.) |
|
|
Ig idiotype
|
- Ig epitope determined by antigen-binding site
|
|
|
IL-1
|
- secreted by macrophages
- stimulates T cells, B cells, neutrophils, fibroblasts and epithelial cells to grow, differentiate or synthesize specific products - an endogenous pyrogen |
|
|
IL-2
|
- Secreted by Th cells.
- Stimulates growth of helper and cytotoxic T cells |
|
|
IL-3
|
- Secreted by activated T cells
- supports the growth and differentiation of bone marrow stem cells - similar function to GM-CSF |
|
|
GM-CSF
|
- granulocyte macrophage colony-stimulating factor
- stimulates production of white blood cells - located on myeloblasts and mature neutrophils, not on any erythroid or megakaryocytic lineage cells |
|
|
IL-4
|
- Secreted by Th2 cells
- Promotes growth of B cells - enhances class switching if IgE and IgG |
|
|
IL-5
|
- Secreted by Th2 cells
- Promotes differentiation of B cells - enhances class switching of IgA - Stimulates production and activation of eosinophils |
|
|
IL-6
|
- Secreted by Th cells and macrophages
- Stimulates production of acute-phase reactants and immunoglobulins |
|
|
IL-8
|
- Major chemotactic factor for neutrophils
|
|
|
IL-10
|
- Secreted by Th2 cells
- Stimulates Th2 while inhibiting Th1 |
|
|
IL-12
|
- secreted by B cells and macrophages
- Activates NK and Th1 cells |
|
|
gamma-interferon
|
- secreted by Th1 cells
- Stimulates macrophages |
|
|
TNF-alpha
|
- Secreted by macrophages
- increases IL-2 receptor synthesis by Th cells - increases B-cell proliferation - Attracts and activates neutrophils - stimulates dendritic cell migration to lymph nodes |
|
|
Helper T cell surface proteins
|
- CD4
- TCR - CD3 - CD28 - CD40L |
|
|
Cytotoxic T cell sufrace proteins
|
- CD8
- TCR - CD3 |
|
|
B cell surface proteins
|
- IgM
- B7 - CD19 - CD20 - CD40 - MHC II |
|
|
Macrophage surface proteins
|
- MHC II
- CD14 - Receptors for Fc and C3b |
|
|
NK cell surface proteins
|
- Receptors for MHC I
- CD 16 - CD56 |
|
|
Membrane attach complex
|
- defends against gram-negative bacteria
- activated by IgG or IgM in the classic pathway - activated by molecules on the surface of microbes (endotoxin) in the alternate pathway - C3b and IgG primary opsonins in bacterial defense |
|
|
Complement:
C1, C2, C3, C4 function |
- viral neutralizaion
|
|
|
C3b
|
opsonizaion
|
|
|
C3a and C5a
|
- anaphylaxis
|
|
|
C5a
|
- neutrophil chemotaxis
|
|
|
C5b-9
|
- cytolysis by MAC
|
|
|
Deficiency of C1 esterase inhibitor
|
- hereditary angioedema (overactive complement)
|
|
|
Deficiency of C3 leads to
|
- severe, recurrent pyogenic sinus and respiratory tract infections
|
|
|
Deficiency of C6-C8
|
- Neisseria bacteremia
|
|
|
Deficiency of decay accelerating factor
|
- paroxysmal nocturnal hemoglobinuria (PNH)
|
|
|
Classic complement pathway
|
- antigen/antibody complexes
(draw) |
|
|
Lectin Complement pathway
|
- microbial surfaces
(draw) |
|
|
Alternative complement pathway
|
- Microbial surfaces (nonspecific activators, endotoxin)
draw |
|
|
Interferon mechanism
|
- alpha, beta and gamma
- proteins that place unifected cells in an antiviral state - induce the production of a 2nd protein that inhibits viral protein synthesis by degrading viral mRNA - activate NK cells to kill virus-infected cells |
|
|
Interferon alpha and beta
|
- inhibit viral protein synthesis
|
|
|
gamma-interferons
|
- increase MHC I and II expression and antigen presentation in all cells
|
|
|
Passive immunity given for:
|
- preformed antibody injection
- Tetanus, botulinum, HBV or Rabies |
|
|
Type I hypersensitivity
|
- Anaphylactic and atopic
- antigen cross-links IgE on presensitized mast cells and basophils - triggers release of vasoactive amines (histamine) - develops rapidly due to preformed antibody |
|
|
Antibody mediated hypersensitivities
|
- type I, II and III
|
|
|
Type II hypersensitivity
|
- Antibody mediated (IgM, IgG
- binds to antigen on enemy cell - lysis by complement or phagocytosis |
|
|
Type III hypersensitivity
|
- Immune complex
- Serum sickness - Arthus reaction |
|
|
Immune complex hypersensitivity
|
- type III
- antigen-antibody complexes activate complement -> attracts neutrophils - neutrophils release lyosomal enzymes |
|
|
Serum sickness
|
- Type III hypersensitivity
- immune complex disease - antibodies to the foreign proteins are produced over 5 days - immune complexes formed and deposited in membranes - fix complement -> tissue damage |
|
|
Arthus reaction
|
- Type III hypersensitivity
- local subacute antibody-mediated hypersensitivity reaction - intradermal injection of antigen induces antibodies - andigen-antibody complexes form in skin - edema, necrosis, activation of complement |
|
|
common problems of serum sickness
|
- often caused by drugs instead of serum
- fever, urticaria, arthralgias, proteinuria, lymphadenopathy - occurs 5-10 days after exposure |
|
|
Type IV hypersensitivity
|
- Delayed (T-cell mediated)
- sensitized T lymphocytes encounter antigen - release lymphokines -> macrophage activation |
|
|
complications of Type IV hypersensitivity
|
- Transplant rejections,
- contact dermatitis - TB skin test uses this mechanism |
|
|
Diseases of type I hypersensitivity
|
- anaphylaxis
- allergic rhinitis (hay fever) |
|
|
Diseases of type II hypersensitivity
|
- Hemolytic anemia
- Idiopathic thrombocytopenic purpura - Erythroblastosis fetalis - Rheumatic fever - Goodpastures's syndrome - Bullous pemphigoid - Graves'disease - Myasthenia gravis |
|
|
Diseases of Type III hypersensitivity
|
- Lupus
- Rheumatoid arthritis - Polyarteritis nodosum - Post-streptococcal glomerulonephritis - Serum sickness - Arthus reaction - Hypersensitivity pneumonitis |
|
|
Diseases of Type IV hypersensitivity
|
- Type I diabetes mellitus
- Multiple sclerosis - Guillain-Barré syndrome - Hashimoto's thyroiditis - Graft-versus-host disease - PPD (test for M. tuberculosis) - Contact dermatitis |
|
|
Immune deficiency causing a decrease in production of B cells
|
- Bruton's agammaglobulinemia
- X-linked recessive defect in a tyrosine kinase gene associated with low levels of all classes of immunoglobulins - recurrent bacterial infections after 6 monts of age (declining maternal IgG - occurs in boys |
|
|
Immune deficiency causing a decrease in production of T cells
|
- Thymic aplasia (DiGeorge syndrome
- Thymus/parathroids fail to develop - failure of development of 3rd and 4th pharyngeal pouches - presents with Tetany owing to hypocalcemia - recurrent viral and fungal infections from T-cell deficiency - congenital defects of heart and great vessels - 22q11 deletion |
|
|
Immune deficiency causing a decrease in production of B and T cells
|
- Severe combined immunodeficiency (SCID)
- Defect in early stem-cell differentiation - presents with recurrent viral, bacterial, fungal and protozoal infections - can have multiple causes (failure to synthesize MHC II antigens, defective IL-2 receptors or adenosine deaminase deficiency. |
|
|
Immune deficiency causing a decrease in activation of T cells
|
- IL-12 receptor deficiency
- Presents with disseminated mycobacterial infections |
|
|
Hyper IgM syndrome
|
- decrease in the activation of B cells
- defect in CD40 ligand on CD4 T helper cells -> inability to class switch - Presents early in life with severe pyogenic infections - High levels of IgM - Very low levels of IgG, IgA and IgE |
|
|
Wiskott-Aldrich syndrome
|
- decrease in B cell activation
- X-linked defect in the ability to mount an IgM response to capsular polysaccharides of pacteria - elevated IgA levels, normal IgE levels, low IgM levels - Triad of symptoms includes recurrent pygenic infections, thrombocytopenic Purpura, Eczema |
|
|
Job's syndrome
|
- decreased activation of Macrophages
- failure of gamma-interferon production by helper T cells - Neutrophils fail to respond to chemotactic stimuli - presents with recurrent "cold" (noninflamed) staphylococcal abscesses, eczema, coarse facies, retained primary teeth, high levels of IgE |
|
|
Leukocyte adhesion deficiency syndrome
|
- Defect in LFA-1 adhesion proteins on phagocytes
- presents early with severe pyogenic and fungal infections - delayed separation of umbilicus |
|
|
Chédiak-Higashi disease
|
- Autosomal recessive
- defect in microtubular function and lysosomal emptying of phagocytic cells - presents with recurrent pyogenic infections by staphylococci and streptococci - partial albinism - peripheral neuropathy |
|
|
chronic granulomatous disease
|
- defect in phagocytosis of neutrophils owing to lack of NADPH oxidase activity or similar enxymes
- presents with marked susceptibility to opportunistic infections with bacteria, esp. S. aureus, E. coli and Aspergillus - diagnosis confirmed with negative nitroblue tetrazolium dye reduction test |
|
|
Chronic mucocutaneous candidiasis
|
- T-cell dysfunction specifically against Candida albicans
- presents with skin and mucous membrane Candida infections |
|
|
Selective Immunoglobulin deficiency
|
- Idiopathic dysfunction of B cells
- Deficiency in a specific class of immunoglobulins (possibly due to defect in isotype switching) - Selective IgA deficiency is most common selective immunoglobulin deficiency - presents with sinus and lung infections, milk allergies and diarrhea common |
|
|
Ataxia-telangiectasia
|
- Idiopathic dysfunction of B-cells
- Defect in DNA repair enzymes with associated IgA deficiency - Presents with cerebellar problems (ataxia) - spider angiomas (telangiectasia) |
|
|
Common variable immunodeficiency
|
- Idiopathic dysfunction of B cells
- Normal numbers of circulating B cells - decreased plasma cells - decreased Ig - can be acquired in 20's and 30's. |
