Immune Responses Flashcards
Classic Pathway Activating Antibodies
- GM makes classic cars
- IgG and IgM
What Activates the Alternative Complement Pathway?
Microbe surface molecules
What activates the Lectin Complement Pathway?
Mannose or other sugars on the microbe surface
What does C3b do?
Binds Bacteria
What do C3a and C5a do?
Anaphylaxis (both) and Neutrophil Chemotaxis (C5a)
The two primary opsonins in bacterial defense
C3b and IgG
What do C5b-9 mediate?
Cytolysis by MAC
C1 Esterase Inhibitor Deficiency leads to
- Hereditary Angioedema
- Edema of skin (esp. Periorbital) and mucosal surfaces.
- ACE Inhibitors are contraindicated
C3 Deficiency leads to
- Severe, recurrent Pyogenic Sinus and respiratory tract infections
- Increased susceptibility to type III HS reactions.
C5-9 Deficiencies lead to
Recurrent Neisseria bacteremia
DAF (GPI anchored enzyme) Deficiency leads to
Complement-mediated lysis of RBC’s and paroxysmal nocturnal hemoglobinuria (PNH)
Cytokines secreted by Macrophages
IL-1, IL-6, IL-8, IL-12, and TNF-alpha
Cytokines secreted by all T cells
IL-2 and IL-3
Cytokine secreted by Th1 cells
Interferon-gamma
Cytokines secreted by Th2 cells
IL-4, IL-5, and IL-10
What do Interferons do?
- INTERFERE with viruses
- Get cells to produce a ribonuclease that inhibits viral protein synthesis by degrading viral mRNA
B cell surface proteins
Ig (binds antigen), CD19, CD20, CD 21 (receptor for EBV), CD40, MHC II, and B7
NK cell Surface Proteins
CD16 (binds Fc of IgG) and CD56 (unique to NK)
Type III HSR mechanism
- Antigen-antibody (IgG) complexes activate complement which attracts neutrophils which then release lysosomal enzymes.
Type II HSR Mechanism
Igm/IgG bind to fixed antigen on “enemy” cell, leading to cellular destruction by opsonization, complement-mediated lysis (C5-9) and Antibody-dependent cell-mediated cytotoxicity (ADCC), usually by NK cells.
Test for Type II HSR
Direct and Indirect Coombs’
Test for Type I HSR
Skin test for IgE
Test for Type IV HSR
Patch test, PPD
4 T’s associated with Type IV HSR
T Lymphocytes, Transplant Rejections, TB Skin Tests, Touching (contact dermatitis)
Immune Complex Disease (type III) in which antibodies to foreign proteins (haptans, bacteria, etc) are produced, complexes are formed and deposited in membranes where they fix complement and produce damage –>
Serum Sickness
Local subacute type III HSR from intradermal injection –> complexes in the skin –> edna, necrosis, and complement activation.
Arthus Reaction
Quick Mnemonic to remember the HSRs
ACID
- Anaphylactic and Atopic (type I)
- Cytotoxic (antibody mediated, type II)
- Immunce Complex (type III)
- Delayed (cell mediated, type IV)
Antinuclear Antibodies (ANA) Associated With
SLE, nonspecific
Rheumatoid Factor, anti-CCP Associated With
Rheumatoid Arthritis
IgA Antiendomysial, IgA anti-tissue transglutaminase Associated With
Celiac Disease
Anti-desmoglein Associated With
Pemphigus Vulgaris
Anti-SSB (anti-La) Associated With
Sjogren’s Syndrome
Anti-smooth muscle Associated With
Autoimmune Hepatitis
p-ANCA (MPO-ANCA) Associated With
Microscopic Polyangiitis, Churg-Strauss Syndrome
Anticentromere Associated With
Scleroderma (CREST syndrome)
Anti-U1 RNP (ribonucleoprotein) Associated With
Mixed Connective Tissue Disease
Anti-glutamate Decarboxylase Associated With
Type I Diabetes Mellitus
Antihistone Associated With
Drug-induced Lupus
Antimitochondrial Associated With
Primary Biliary Cirrhosis
Anti-SSA (anti-Ro) Associated With
Sjogren’s Syndrome
c-ANCA (PR3-ANCA) Associated With
Granulomatosis with polyangiitis (Wegener’s)
Anti-Jo-1, anti-SRP, anti-Mi-2 Associated With
Polymyositis, dermatomyositis
Antimicrosomal, antithyroglobulin Associated With
Hashimoto’s Thyroiditis
Anti-basement membrane Associated With
Goodpasture’s Syndrome
Anti-Scl-70 (anti-DNA topoisomerase I) Associated With
Scleroderma (diffuse)
Anti-dsDNA, anti-Smith Associated With
SLE
What do alpha and beta interferons do specifically?
The inhibit viral protein synthesis.
What does gamma interferon do specifically?
Increase MHC I and II expression and antigen presentation in all cells.