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129 Cards in this Set
- Front
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Immuno FA
Patient with Mycoplasma pneumoniae exhibits cryagglutination during recovery phase. What type of immunoglobulina are reacting? |
IgM
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Immuno FA
Young child presents with tetany and candidiasis. Hypocalcemia and immunosuppression are found: |
DiGeorges (Tcell deficient)
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Immuno FA
Young child has recurrent lung infections and granulomatous lesions. What is the defect in neutrophils? |
NADPH oxidase (chronic granulomatous disease)
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Immuno FA
What are the three functions of a lymphnode? |
1. nonspecific filtration by macrophages
2. storage/proliferation of B and T cells 3. antibody production 3. |
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Immuno FA
What is the function of the follicle of the lymphnode? |
Site of b-cell proliferation and localization.
Follicles are located in the outer cortex. There are primary and secondary follicles: primary = dense and dormant; secondary = active and have pale germinal centers |
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Immuno FA
What is the function of the medulla of the lymph node? |
Medulla: consists of medullary cords that are closely packed with lymphocytes and plasma cells.
There are also medullary sinuses within the medulla. These sinuses communicate with efferent lymphatics and contain reticular cells and macrophages. MMM: Medually sinuses and cords; Megakaryocyte babies = platelets and lymphos; Macro's and reticular cells |
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Immuno FA
What is the function of the pancortex of the lymphnode? |
Pancortex: home for t-cells
Region of the cortex between follicles and medulla that contains high endothelial venuls through which T and B cells enter from blood. In extreme cellular immune response, paracortex becomes enlarged. This cortex is not well developed in DiGeorges. |
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Immuno FA
What are the two ways lymph can drain? |
Right lymphatic duct (drains right arm and right half of head)
Thoracic duct: drains everything else. |
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Immuno FA
Describe the spleen sinusoids: Explain red pulp vs white pulp. |
They are long vascular channels in the red pulp of the spleen with fenestrated "barrel hoop" basement membrane.
Macrophages are found nearby. With T-cells found in the periarterial lymphatic sheath (PALS) and in the red pulp of the spleen. B cellls are found in follicles within the white pulp of the spleen. The white pulp also contains T-cells and functions to fight infections |
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Immuno FA
What is the derivation of the thymus? |
Thymus: from epithelium of 3rd branchial pouches
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Immuno FA
Describe the thymus? |
Thymus is encapsulated
Thymus is the site of t-cell differention (as is bone to b-cells). Its cortex is dense with immature T-cells and its medulla is pale with mature T cells and epithelial reticular cells as well as containing Hassall's corpuscles. |
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Immuno FA
What are Hassels corpuscles |
Currently unknown.
Thought to direct the maturation of dendritic cells |
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Immuno FA
What occurs at the corticomedullary junction in the thymus (2) |
1. positive selection (MHC restriction)
2. negative selection (nonreactive to self) |
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Immuno FA
Describe innate immunity: |
Response to pathogens that is fast and nonspecific.
Receptors that recognize pathogens are germline encoded. Consists of neutrophils, macrophages, dendritic cells, and complement No memory |
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Immuno FA
Describe adaptive immunity: |
Receptors that recognize pathogens undergo VDJ recombination during lymphocyte development.
Response is slow on first exposure but the memory response is faster. Consists of T-cells, B-cells, and circulating antibody. |
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Immuno
What is the function of CD8 Tcells |
CD8 Tcells are declared as such in the thymus and are brought to the lymph node --> cytotoxic T-cell.
These cells bind MHC class I and kill virus-infected cells directly. |
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Immuno
What is the function of helper t-cells? |
Th1: makes IL-2 amd IGN-gamma activating cytotoxic T-cells and macrophages.
Th2: produces IL-2, IL-4, and IL-5 to provide help for B-cells to make antibody. (IgE > IgG) |
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Immuno
What encodes MHC? |
Human Leukocyte Antigen (HLA genes)
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Immuno
Describe MHC I: |
MHC-1: HLA-A, HLA-B, HLA-C
expressed on all nucleated cells antigen is loaded in RER of mostly intracellular peptides mediates viral immunity pairs with beta 2-immunoglobulin |
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Immuno
Describe MHC II: |
MHC II
HLA-DR,-DP,-DQ expressed only on antigen presenting cells (APCs) Antigen is loaded in an acidified endosome Main determinants of organ rejection |
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Immuno
What are the major functions of B-cells? |
To make antibody
For IgG it is used to opsonize bacteria and viruses. IgE is used in allergic reactions Also, antibodies cause organ rejection (fast) |
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Immuno
What are the major functions of T-cells? |
CD4+ t-cells help b-cells make antibody and produce gamma-interferon that activates macrophages
The CD8+ T cells that kill virus infected cells directly Induce allergy of type IV hypersensitivity Cause slow organ rejection |
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Immuno
What is the identifying marker of tcells? bcells? |
T-cell: CD3 (which forms a complex around TCR), CD4 or CD8, CD 28 (which binds to B7 on APC -- done by Th cells)
B-cells: have CD-19 and CD-20 and have antibodies on their surface to bind to virus particles or antigens |
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Immuno
What are three APC's? |
B-cells
Macrophage Dendritic cell |
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Immuno
What two signals are required for Th activation? |
Signal 1 and Signal 2
Th activation: Foreign body is phagocytosed by APC Foreign antigen is presented on MHC II and recognized by TCR on Th cell (Signal 1) Costimulatory signal is given by interaction with B7 and CD28 (signal 28) |
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Immuno
What two signals are required for Tc activation? |
Endogenously synthesized (viral or self) proteins are presented on MHC I and recognized by TCR on Tc cell (signal 1)
Il-2 from Th cell activates Tc cell to kill virus-infected cell (signal 2) |
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Immuno
Antibody structure What does the variable part of L and H chains do? |
They recognize antigens
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Immuno
Antibody structure What does the constant part of the H chain of IgM and IgG do? |
It fixes complement
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Immuno
What is a Fab fragment? |
RR, p.27
Fab fragment: portion of antibody molecule, produced by papain digestion, that contains a single antigen binding site. All antibodies have two or more Fab regions and thus are bivalent or multivalent. FA: heavy chains and light chains contribute to the Fab fragments |
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Immuno
What is a Fc fragment? |
FA: p.188
Constant, Carboxyterminal, Complement-binding (IgG+IgM only), Carbohydrate side chain, Complement binding fragment RR, p.27 Postion of antibody molecule, produced by papain digestion, that fixes complement and binds to Fc receptors; varies among immunoglobulin types. Has only a heavy chain component |
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Immuno
What causes antibody diverisity? |
1. random "recomination" of VJ (lightchain) and VDJ (heavy chain) genes
2. random combination of heavy chains with light chains 3. somatic hypermutation 4. addition of nucleotides to DNA during "genetic recombination" by terminal deoxynucleotidyl transferase |
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IMMMUNO-CANCER
Causes & Effects of: Small cell lung carcinoma? |
Causes: ACTH or ACTH-like peptide
Effects: Cushing's syndrome |
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IMMMUNO-CANCER
Causes & Effects of: Small cell lung carcinoma and intracranial neoplasms? |
Causes: ADH
Effect: SIADH |
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IMMMUNO-CANCER
Causes & Effects of: Squamous cell lung carcinoma, renal cell carcinoma, breast carcinoma, multiple myeloma, and bone metastasis (lysed bone)? |
Causes: PTH-related peptind, TGF-Beta, TNF-alpha, IL-1
Effects: Hypercalcemia |
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IMMMUNO-CANCER
Causes & Effects of: Renal cell carcinoma, hemangioblastoma? |
Causes: Erythropoietin
Effects: Polycythemia |
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IMMMUNO-CANCER
Causes & Effects of: Thymoma, small cell lung carcinoma? |
Causes: Antibodies against presynaptic Ca2+ channels at neuromuscular juntion
Effects: Lambert-Eaton syndrome (muscle weakness) |
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IMMMUNO-CANCER
Causes & Effects of: Leukemias and lymphomas? |
Causes: Hyperuricemia due to excess nucleic acid turnover (i.e., cytotoxic therapy)
Effects: Gout, urate nephropathy |
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IMMMUNO-CANCER
What is 1 degree tumors that metastasize to brain? |
Lung, Breast, Skin (melanoma), Kidney (renal cell carcinoma), GI. Overall, approx 50% of brain tumors are from metastases.
Lots of Bad Stuff Kills Glia. Typically multiple well-circumscribed tumors at gray-white border. |
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IMMMUNO-CANCER
What are the most common sites of metastasis after the regional lymph nodes: |
The liver and lung.
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IMMMUNO-CANCER
1 degree tumors that metastasize to the liver? |
Colon > Stomach > Pancreas > Breast > Lung.
Metastases >> 1 degree liver tumors. Cancer Sometimes Penetrates Benign Liver. |
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IMMMUNO-CANCER
What 1 degree tumors metastasize to bone? |
Prostate, Thyroid, Testes, Breast, Lung, Kidney.
Metastases from breast and prostate are most common. Metastatic bone tumors are far more common than 1 degree bone tumors. P.T. Barnum Loves Kids. Lung = Lytic. Prostate = blastic. Breast = Both lytic and blastic |
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IMMMUNO-CANCER
What is the cancer incidence in males? |
Prostate (32%)
Lung (16%) Colon and rectum (12%) |
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IMMMUNO-CANCER
What is the cancer incidence in females? |
Breast (32%)
Lung (13%) Colon and rectum (13%) |
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IMMMUNO-CANCER
What is the cancer mortality in males? |
Lung (33%)
Prostate (13%) |
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IMMMUNO-CANCER
What is the cancer mortality rate in females? |
Lung (23%)
Breast (18%) |
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Immunodeficiency
Decreased production of B cells causes: |
Bruton's agammaglobulinemia:
X-linked recessive defect in a tyrosine kinase gene assoc with low levels of all classes of immunoglobulins. Assoc with recurrent Bacterial infections after 6 months of age, when lefels of maternal IgG antibody decline. Occurs in Boys (X-linked). |
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Immunodeficiency
What immunodeficiency decreases production of T-cells? |
Thymic aplasia (DiGeorge syndrome)
Thymus & parathyroids fail to develop owing to failure of development of the 3rd and 4th pharyngeal pouches. Presents with Tetany owing to hypocalcemia. Recurrent viral and fungal infections due to T-cell deficiency. Congenital defects of heart and great vessels. 22q11 deletion. |
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Immunodeficiency
What immunodeficiency decreases 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. May have multiple causes (e.g., failure to synthesize MHC II antigens, defective IL-2 receptors, or adenosine deaminase deficiency). |
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Immunodeficiency
What immunodeficiency decreases activation of T cells? |
Il-12 receptor deficiency
Presents with disseminated mycobacterial infections. |
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Immunodeficiency
What immunodeficiency decreases activation of B cells and causes IgM syndrome? Describe. |
Defect in CD40 ligand on CD4 T helper cells leads to inability to class switch. Presents early in life with severe pyogenic infections. High levels of IgM; very low levels of IgG, IgA, and IgE.
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Immunodeficiency
What immunodeficiency deacreases activation of B cells and causes Wiskott-Aldrich syndrome? Describe. |
X-linked defect in the ability to mount an IgM response to capsular polysaccharides of bacteria. Associated with elevated IgA levels, normal IgE levels, and low IgM levels. Triad of symptoms includes recurrent pyogenic Infections, thrombocytopenic Purpura, Eczema (WIPE).
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Immunodeficiency
What immunodeficiency deacreases activation of Macrophages? |
Job's syndrome.
Failure of gamma-interferon production by helper T cells. Neutrophils fail to respond to chemotactic stimuli. Presents with recurrent "cold" (noninflamed) staphylococcal absceses,eczema, coarse facies, retained primary teeth, and high levels of IgE. |
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Immunodeficiency
Phagocytic cell deficiency causes Leukocyte adhesion deficiency syndrome. Describe? |
Defect in LFA-1 adhesion proteins on phagocytes. Presents early with eevere pyogenic and fungal infections and delayed separation of umbilicus.
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Immunodeficiency
Phagocytic cell deficiency causes Chediak-Higashi disease. Describe? |
Autosomal recessive. Defect in microtubular function and lysosomal emptying of phagocytic cells. Present swith recurrent pyogenic infections by staphylococci and streptococci, partial albinism, and peripheral neuropathy.
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Immunodeficiency
Phagocytic cell deficiency causes Chronic granulomatous disease. Describe? |
Defect in phagocytosis of neutrophils owing to lack of NADPH oxidase activity or similar enzymes. Presents with marked susceptibility to opportunistic infections with bacteria, especially S. aureaus, E., coli, and Aspergillus. Diagnosis confirmed with negative nitroblue tetrazolium dye reduction test.
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Immunodeficiency
Idiopathic dysfunction causes chronic nucocutaneous candidiases in T cells. Describe? |
T-cell dysfunction specifically against Candida albicans. Presents with skin and mucouse membraine Candida infections.
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Immunodeficiency
Idiopathic dysfunction causes selective immunoglobulin deficiency in B cells. Describe? |
Deficiency in a specific class of immunoglobulins - possibly due to a defect in isotype switching. Selective IgA deficiency is the most common selective immunoglobulin deficiency. Presents with sinus and lung infections; milk allergies and diarrhea are common.
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Immunodeficiency
Idiopathic dysfunction causes ataxia-telangiectasia in B cells. Describe? |
Defect in DNA repair enzymes with associated IgA deficiency. Presents with cerebellar problems (ataxia) and spider angiomas (telangiectasia).
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Immunodeficiency
Idiopathic dysfunction causes common variable immunodeficiency in B cells. Describe? |
Normal numbers of circulating B cells, decreased plasma cells, decreased Ig, can be acquired in 10's-30's
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IMMUNO
What disorder is assoc'd with: Antinuclear antibodies (ANA)? |
SLE
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IMMUNO
What disorder is assoc'd with: Anti-dsDNA, anti-Smith |
Specific for SLE
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IMMUNO
What disorder is assoc'd with: Antihistone? |
Drug-induced lupus
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IMMUNO
What disorder is assoc'd with: Anti-IgG (rheumatoid factor)? |
Rheumatoid arthritis
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IMMUNO
What disorder is assoc'd with: Antineutrophil (C-ANCA, P-ANCA)? |
Vasculitis
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IMMUNO
What disorder is assoc'd with: Anticentromere? |
Seleroderma (CREST)
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IMMUNO
What disorder is assoc'd with: Anti-Sel-70? |
Seleroderma (diffuse)
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IMMUNO
What disorder is assoc'd with: Antimitochondrial? |
1 degree biliary cirrhosis
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IMMUNO
What disorder is assoc'd with: Antigliadin? |
Celiac disease
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IMMUNO
What disorder is assoc'd with: Anti-basement membrane? |
Goodpasture's syndrome
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IMMUNO
What disorder is assoc'd with: Anti-epithelial cell? |
Pemphigus vulgaris
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IMMUNO
What disorder is assoc'd with: Antimicrosomal? |
Hashimoto's thyroiditis
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IMMUNO
What disorder is assoc'd with: Anti-Jo-1 |
Polymyositis, dermatomyositis
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IMMUNO
HLA subtypes: B27 |
Psoriasis, Ankylosing spondylitis, Inflammatory bowel disease, Reiter's syndrome.
PAIR |
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IMMUNO
HLA subtypes: B8 |
Graves' disease, celiac spruc
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IMMUNO
HLA subtypes: DR2 |
Multiple selerosis, hay fever, SLE, Goodpasture's.
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IMMUNO
HLA subtypes: DR3 |
Diabetes mellitus type 1,.
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IMMUNO
HLA subtypes: DR4 ? |
Rheumatoid arthritis, diabetes mellitus type 1
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IMMUNO
HLA subtypes: DR5 ? |
Pernicious anemia --> B12 deficiency, Hashimoto's thyroiditis.
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IMMUNO
HLA subtypes: DR7 ? |
Steroid-responsive nephrotic syndrome.
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IMMUNO
Transplant rejection: Hyperacute rejection. Describe? |
Antibody mediated due to the presence of preformed antidonor antibodies in the transplant recipient. Occurs within minutes after transplantation.
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IMMUNO
Transplant rejection: Acute rejection. Describe? |
Cell mediated due to cytotoxic T lymphocytes reacting against foreign MHCs. Occurs weeks after transplantation. Reversible with immunosuppressants such as cyclosporin and OKT3.
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IMMUNO
Transplant rejection: Chronic rejection. Describe? |
Antibody-mediated vascular damage (fibrinoid necrosis); occurs months to years after transplantation. Irreversible.
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IMMUNO
Transplant rejection: Graft-versus-host disease. Describe? |
Grafted immunocompetent T cells proliferate in the irradiated immunocompromised host and reject cells with "foreign" proteins, resulting in severe organ dysfunction. Major symptoms include a maculopapular rash, jaundice, hepatosplenomegaly, and diarrhea.
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Immuno
IL-1 |
Secreted by macrophages.
Stimulates T and B cells, neutrophils, fibroblasts, and epithelial cells to grow, differentiate, or synthesis specific products (an endogenous pyrogen) |
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Immuno
IL-2 |
Secreted by Th cells.
Stimulates growth of helper and cytotoxic t-cells |
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Immuno
IL-3 |
Secreted by activated T cells
Supports growth of B cells Enhances class switching of IgE and IgG |
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Immuno
IL-4 vs IL-5 |
IL-4 and 5
Both are secreted by Th2 cells. IL-4: promotes growth of B cells and enhances class switching of IgE and IgG IL-5: promotes differentiation of B cells. Enhances class switching of IgA. Stimulates production and activation of eosinophils |
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Immuno
IL-6 |
Secreted by Th cells and macrophages.
Stimulates production of acute-phase reactants and immunoglobulins |
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Immuno
IL-8 |
major chemotactic factor for neutrophils.
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Immuno
IL-10 |
Secreted by Th2 cells while inhibiting Th1
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Immuno
IL-12 |
Secreted by B cells and macrophages
Activates NK and Th1 cells |
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Immuno
gamma interferon |
Secreted by Th1 cells.
Stimulates macrophages |
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Immuno
TNF-alpha |
Secreted by macrophages.
Increase IL-2 receptor synthesis by Th cells Increase B-cell proliferation Attracts and activates neutrophils Stimulates dendritic cell migration to lymph nodes |
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Immuno
Cell surface proteins for: Helper T cells Cytotoxic T cells B cells Macrophages NK cells All cells except mature RBCs |
Helper T
CD4, TCR, CD3, 28, 40L Cytotoxic CD8, TCR, CD3 B cells IgM, B7, CD 19,20,40, MHC II Macophages MHC II, CD 14, receptors for Fc and C3b NK cells receptors for MHC I, CD16, CD56 All cells except mature RBC's: MHCI |
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Immuno
What is the mechanism of interferons? |
Interferons are proteins that place uninfected cells in an antiviral state.
Interferons induce a production of a 2nd protein that inhibits viral protein synthesis by degrading viral mRNA (but not host mRNA) |
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Immuno
What are the functions of alpha, beta, and gamma interferon? |
INTERFERes with viruses:
alpha and beta: inhibit viral protein synthesis gamma interferons increase MHCI and II expression and antigen presentation in all cells They all activate NK cells to kill virus-infected cells. |
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Immuno
Complement: Function of C1, C2, C3, C4? |
All are for viral neutralization
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Immuno
Complement: Function of C3b |
Opsonization
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Immuno
Complement Function of C3a and C5a |
Anaphylaxis (stimulate mast cells to release histamine)
and C5a also is a neutrophil chemotaxant |
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Immuno
Complement Function of C5b,6,7,8,9 |
cytolysis by membrane attack complex (MAC)
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Immuno
Complement Deficiency of C1 esterase? |
C1 esterase inhibitor leads to hereditary angioedema (overactive complement)
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Immuno
Complement Deficiency of C3? |
Leads to severe, recurrent pyogenic sinus and respiratory tract infections
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Immuno
Complement Deficiency of C6-8 |
Leads to Neisseria bacteremia
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Immmuno
Complement Deficiency of decay accelerating factor (DAF) |
DAF increases degradation of C3 and C5 convertase protecting against MAC.
This deficiency would cause paroxysmal nocturnal hemoglobinuria |
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Complement:
C2 deficiency? |
Increase incidence of autoimmune dz like SLE
(MC hereditary complement deficiency) |
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Immuno
Does IgA fix complement? |
No
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Immuno
Characteristics of IgM |
Produced in the primary response to an antigen.
Fixes complement but does not cross the placenta. Antigen receptor on the surface of B cells. Monomer or polymer Involved in cold-agglutin |
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Immuno
Compare Ig isotype to idiotype |
Isotype: the Ig epitope common to a single class of Ig (5 classes, determined by heavy chain)
Idiotype (specific for a specific antigen): determined by antigen-binding site thus the hypervariable region since it is unique |
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Immuno
The Fab fragment of an antibody is composed of light and heavy chains and the heavy chain in the Fab fragment is the hypervariable region (constant part of the H chain of IgM and IgG fixes complement) What characteristics does the Fc fragment have? |
Fc: (4C's)
Constant Carboxyl terminal Complement-binding (IgG and IgM only) Carbohydrate side chains |
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Immuno
Four causes of antibody diversity: |
1. random "recombination" of VJ (light-chain) or VDJ (heavy chain) genes
2. random combination of heavy chains with light chains 3. somatic hypermutation 4. addition of nucleotides to DNA during "genetic recombination" by terminal deoxynucleotidyl transferase |
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Immuno
Major function of B and T cells: |
Bcells:
make Ab IgG antibodies then opsonize bacteria and viruses IgE cause type I hypersensitivity These antibodies also cause organ rejection (fast) T-cells CD4+ tcells help B cells make antibody and produce gamma interferon that activates macrophages Kills virus-infected cells directly (CD8+ T cells) Allergy inducers via Type IV hypersensitivity Organ rejection (slow) |
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Immuno
What MHC do APC's present? Who do they present to? |
APC's present on MHC II (only on APC's) and they present to CD4 t-cells which are Th cells.
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Immuno
What two signal are required for T-cell activation in the Th cell? |
Th cell activation:
1. foreign body is phagocytosed by APC 2. Foreign antigen is presented on MHC II and recognized by TCR on Th cell (signal 1) 3. "Costimulatory signal" is given by interaction of B7 and CD28 4. Th cell activated to produce cytokines |
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Immuno
What two signal are required for T-cell activation in the Th cell? |
Tc activation:
1. Endogenously synthesized (viral or self) proteins are presented on MHC I and recognized by TCR on Tc cell (signal 1) 2. IL-2 from Th cell activates Tc cell to kill virus-infected cell (signal 2) |
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Immuno
What MHC mediates viral immunity? |
MHC I
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Immuno
What are the characteristics of MHC I: |
MHC I: HLA-A,-B,-C
Expressed on almost all nucleated cells Antigen is loaded in RER of mostly intracellular peptides Mediates viral immunity Pairs with beta2-immunoglobulin |
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Immuno:
What are the characteristics of MHC II: |
MHC II: HLA-DR, HLA-DP, HLA-DQ
Expressed only on antigen presenting cells Antigen is loaded in an acidified endosome Main determinants of organ rejection |
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Immuno:
Anergy |
Self-reactive Tcells become nonreactive without costimulatory molecule. B cells also become anergic, but tolerance is less complete than in T-cells.
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Immuno:
Describe a Type I hypersensitivity rxn: |
Anaphylactic and atopic:
IgE dependant that causes an allergic response and is great for parasites and toxin neutralization Initiation: cross-linkage by antigen (allergen) of IgE bound to Fc receptors on the mast cells and basophils following reexposure of sensitized host to allergen 2. Effector mechanism: degranulation of mast cells and basophils releasing vasoactive mediators such as histamine and SRS-A (slow-reacting substance anaphylaxis) 3. Clinical manifestations: either acute genealized anaphylaxis (shock, vascular collapse, resp collapse) or chronic recurrent localized reactions: asthma, allergic rhinitis (hay fever), wheal and flare (hives) Rx: desensitization therapy - repeated injections of increasing doses of allergen induce production of IgG which binds to allergen and prevents its binding to IgE on sensitized cells. |
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Immuno:
Describe a Type II hypersensitivity rxn: |
Type II hypersensitivity:
1. initiation: binding of antibody to cell surface antigens 2. effector mechanisms involve complement activated by cell surface antigen-antibody complex. Antibody-dependant cellular cytoxicity triggered by binding of antibody to Fc receptors on macrophages and NK cells --> cell destruction. Clinical manifestations: 1. hemolytic transfusion reaction - antibodies to RBC antigens 2. drug-induced thrombocytopenia and hemolytic anemia (Abs to drugs absorbed on platelets on RBCs) 3. Hemolytic dz of the newborn (erythroblastosis fetalis) maternal Ab to antigens 4. Autoimmune dz (RR p.43) |
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Immuno:
Describe a Type III hypersensitivity rxn: |
Type III: immune complex-induced tissue-damaging inflammation
1. Initiation: formation of large amts of circulating antigen-antibody (immune) complexes and their deposition in various tissues or on vessel walls. 2. Effector mechanism: activation of the complement cascade (by immune complexes) Clinical manifestations: Arthus reaction - local skin rxn (redness and swelling) induced by intradermally injected antigen or insect bite. Can also be intrapulmonary from inhalation of bacterial spores or fungi (farmers) Serum sickness: generalized reaction developing 1-2wks after administration of foreign serum (in passive immunization). Penicillin and other drugs can cause similar reactions marked by fever, lymphadenopathy, and arthralgia. There are also vasculitis, nephritis, and arthritis associated with infections and autoimmune disease. |
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Immuno:
Describe a Type IV hypersensitivity rxn: |
Type IV: delayed type
Initiation: antigen stimulated release of cytokines (IL-2, INF gamma, TNF beta) from sensitized (activated) CD4 TH1 cells. Effector mech: Primary inflam response: recruitement and activation of macrophages, which kill microbes and release various substances responsible for local inflammation and tissue damage. Secondary cytotoxic response: activation of CD8 Tc cells and killing of target cells bearing antigen associated with class I MHC molecules Clinical manifestations and examples: Contact dermatitis (eczema and many macrophages) Tuberculin reaction: local induration and swelling, Tcells, and fewer macrophages Graft rejections Granuloma formations (nodule composed of epithelioid cells, giant cells, and macrophages, fibrosis, necrosis) |
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Immuno:
What is sleeping sickness? |
Serum sickness: an immune complex disease (type III) in which antibodies to the foreign proteins are produced (takes 5 days). Immune complexes form and are deposited in membranes, where they fix complement (leads to tissue damage).
These are more common than Arthus. Most serum sickness is now caused by drugs (not serum). Fever, urticaria, arthralgias, proteinuria, lymphadenopathy 5-10d post exposure. |
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Immuno:
Describe an immune complex: |
Three things stuck together:
Antigen, Antibody, Complement |
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Immuno:
What are the four T's of Type IV hypersensitivity reaction? |
T lymphocytes
Transplant rejections TB skin tests Touching (contact dermatitis) |
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Immuno:
Three causes of type I hypersensitivity: |
Anaphylaxis
Allergic rhinitis Pen allergy that responds with rash |
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Immuno:
9 causes of type II hypersens: |
Type II
1. Hemolytic anemia 2. Idiopathic thrombocytopenic purpura 3. Erythroblastosis fetalis 4. Rheumatic fever 5. Goodpastures syndrome 6. Bullous pemphigoid 7. Grave's dz 8. Myasthenia gravis (autoantibody against nictotinic acetylcholine receptors on skel m.) |
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Immuno
9 causes of Type III hypersensitivity |
1. Lupus (mixed II and III)
2. Rheumatoid arth (mixed III and IV) 3. Polyarteritis nodosum (HBsAg + antiHBS IC's) 4. Post-strept glomerulonephritis 5. Serum sickness 6. Arthus reaction 7. Hypersens pneumo (mixed III and IV) 8. Henoch-Scholein purpura (antiIgA) 9. Parvovirus B19 |
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Immuno
9 causes of Type IV hypersensitivity reactions: |
1. Type I DM (mixed III and IV)
2. Multiple sclerosis 3. Guillain-Barre syndrome 4. Hashimotos thyroiditis (type II and IV) 5. Graft vs host dz 6. PPD 7. Contact dermatitis (eczema) 8. Acute transplant rejection (II and IV) 9. Pernicious anemia (II and IV) |
