MICROBIOLOGY & IMMUNOLOGY
MICRO: Immunology
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| -?-(d) IgD | Unclear function; found on the surface of many B cells & in serum |
| -?-(b) IgA | Prevents attachment of bacteria & viruses to mucous membranes, does not fix complement; monomer or dimmer; found in secretions; picks up secretory component from epithelial cells before secretion |
| -?-(e) IgE | Mediates immediate (type 1) hypersensitivity by inducing the release of mediators from mast cells & basophils when exposed to allergen; mediates immunity to worms; lowest concentration in serum |
| -?-(a) IgG | Main antibody in 2° response; most abundant; fixes complement, crosses the placenta, opsonizes bacteria, neutralizes bacterial toxins & viruses |
| -?-(c) IgM | Produced in the 1° response to an antigen; fixes complement but does not cross the placenta; antigen receptor on the surface of B cells; monomer or pentamer |
| (a) IgG (b) IgA (c) IgM (d) IgD (e) IgE | |
| -?-allotype | differs among members of same species |
| -?-isotype | common to a single class of Ig |
| -?-idiotype | determined by antigen-binding site |
| -?-(d) IL-4 | Secreted by helper T cells; promotes growth of B cells; enhances the synthesis of IgE & IgG |
| -?-(h) TNF-α | Secreted by macrophages; ↑ IL-2 receptor synthesis by helper T cells; ↑ B-cell proliferation; attracts & activates neutrophils |
| -?-(i) TNF-β | Secreted by activated T lymphocytes; functions similar to those of TNF-Α |
| -?-(b) IL-2 | Secreted by helper T cells; stimulates growth of helper & cytotoxic T cells |
| -?-(g) γ-interferon | Secreted by helper T cells; stimulates macrophages |
| -?-(c) IL-3 | Secreted by activated T cells; supports the growth & differentiation of bone marrow stem cells; has a function similar to GM-CSF |
| -?-(a) IL-1 | Secreted by macrophages; stimulates T cells, B cells, neutrophils, fibroblasts, & epithelial cells to grow, differentiate or synthesize specific products; an endogenous pyrogen |
| -?-(e) IL-5 | Secreted by helper T cells; promotes differentiation of B cells; enhances the synthesis of IgA; stimulates production & activation of eosinophils |
| -?-(f) IL-8 | Major chemotactic factor for neutrophils |
| (a) IL-1 (b) IL-2 (c) IL-3 (d) IL-4 (e) IL-5 (f) IL-8 (g) Γ-interferon (h) TNF-Α (i) TNF-Β | |
| -?-(d) macrophages | MHC II, CD14: |
| -?-(f) all cells except mature red cells | MHC I: |
| -?-(a) helper T cells | CD4, TCR, CD3, CD28: |
| -?-(c) B cells | IgM, B7, CD19, CD20: |
| -?-(b) cytotoxic T cells | CD8, TCR, CD3: |
| -?-(e) NK cells | Receptors for MHC I, CD16: |
| (a) ) helper T cells (b) cytotoxic T cells (c) B cells (d) macrophages (e) NK cells (f) all cells except mature red cells | |
| -?-(b) cytotoxic | IgM, IgG bind to antigen on "enemy" cell, leading to lysis (by complement) or phagocytosis |
| -?-(a) anaphylactic & atopic | Antigen cross-links IgE on presensitized mast cells & basophis, triggering release of vasoactive amines |
| -?-(e) arthus reaction | A local subacute antibody-mediated hypersensitivity (type III) reaction; intradermal injection of antigen induces antibodies, which form antigen-anibody complexes in the skin |
| -?-(c) immune complex | Antigen-antibody complexes activate complement, which attracts neutrophils; neutrophils Release lysosomal enzymes |
| -?-(f) delayed (cell-mediated) type | Sensitized T lymphocytes encounter antigen & then release lymphokines (leads to macrophage Activation) |
| -?-(d) serum sickness | An immune complex disease (type III) in which antibodies to the foreign proteins are produced (takes 5 days); immune complexes form & are deposited in membranes, where they fix complement (leads to tissue damage) |
| (a) anaphylactic & atopic (b) cytotoxic (c) immune complex (d) serum sickness (e) arthus reaction (f) delayed (cell-mediated) type | |
B-cell deficiencies:
Bruton's agammaglobulinemia deficiency: X-linked recessive defect in a tyrosine gene associated with low levels of all classes of: -?-immunoglobulins.
Selective immunoglobulin deficiency: Deficiency in a specific class of immunoglobins-possibly due to a defect in -?-isotype switching.
T-cell deficiencies:
thymic aplasia (DiGeorge syndrome): thymus & parathyroids fail to develop owing to failure of the development of the 3rd & 4th -?-pharyngeal pouches.
chronic mucocutaneous candidiasis: T-cell dysfunction specifically against -?-Candida albicans; presents with skin & mucous membrane
B- and T-cell deficiencies:
Severe combined immunodeficiency: defect in early stem-cell differentiation; presents with recurrent viral, bacterial, fungal, and -?-protozoal infections; may have multiple causes.
Wiskott-Aldrich syndrome: X-linked defect in the ability to mount an -?-IgM response to capsular polysaccharides of bacteriua.
Ataxia-telangiectasia: Defect in DNA repair enzymes with associated IgA deficiency; presents with -?-ataxia and telangiectasia.
Phagocytic deficiencies:
Chronic granulomatous disease: defect in phagocytosis of neutrophils owing to lack of -?-NADPH oxidase activity or similar enzymes.
Chédiak-Higashi disease: autosomal recessive; defect in microtubular function & lysosomal emptying of phagocytic; presents with recurrent -?-NADPH infections by staphylococci & streptococci.
Job's syndrome: failure of -?-γ-interferon production by helper T cells; neutrophils fail to respond to chemotactic stimuli.
Leukocyte adhesion deficiency syndrome: defect in -?-LFA-1 adhesion proteins on phagocytes; presents early in life with severe pyogenic infections.
Hyper-IgM syndrome: defect in CD40 ligand on CD4 T helper cells leads to inability to class switch; presents early in life with severe -?-pyogenic infections.
IL-12 receptor deficiency: presents with disseminated -?-mycobacterial infections.
Active immunity: induced after exposure to foreign -?-antigens; slow onset; long-lasting protection (memory).
Passive immunity: based on receiving performed -?-antibodies from another host; rapid onset; short life span of antibodies.
| -?-(g) anti-Scl-70 | Scheroderma (diffuse) |
| -?-(l) antimicrosomal | Hashimoto's thyroiditis |
| -?-(a) ANA (antinuclear antibodies) | SLE |
| -?-(b) anti-dsDNA, anti-Smith | Specific for SLE |
| -?-(k) anti-epithelial cell | Pemphigus vulgaris |
| -?-(c) antihistone | Drug-induced lupus |
| -?-(d) anti-IgG | Rheumatoid arthritis |
| -?-(e) antineutrophil | Vasculitis |
| -?-(f) anticentromere | Schleroderma (CREST) |
| -?-(h) antimitochondrial | 1° biliary cirrhosis |
| -?-(j) anti-basement membrane | Goodpasture's syndrome |
| -?-(i) antigliadin | Celiac disease |
| (a) ANA (b) anti-dsDNA, anti-Smith (c) antihistone (d) anti-IgG (e) antineutrophil (f) anticentromere (g) anti-Scl-70 (h) antimitochondrial (i) antigliadin (j) anti-basement membrane (k) anti-epithelial cell (l) antimicrosomal | |
| -?-(d) graft-vs-host disease | Grafted immunocompetent T cells profliferate in the irradiated immunocompromised host & reject cells with "foreign" proteins, resulting in severe organ dysfunction; major symptoms include a maculopapular rash, jaundice, hepatosplenomegaly & diarrhea |
| -?-(c) chronic rejection | Antibody-mediated vascular damage (fibrinoid necrosis); occurs months to years after transplantation; irreversible |
| -?-(b) acute rejection | Cell mediated due to cytotoxic T lymphocytes reacting against foreign MHCs; occurs weeks after transplantation; reversible with immunosuppressants such as cyclosporine & OKT3 |
| -?-(a) hyperacute rejection | Antibody mediated due to the presence of preformed anti-donor antiboidies in the transplant recipient; occurs within minutes after transplantation |
| (a) hyperacute rejection (b) acute rejection (c) chronic rejection (d) graft-vs-host disease | |