Term
What is needed for B cell survival?
What is needed for B cell receptor activation? |
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Definition
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Term
Name 3 Fc-gamma receptors on leukocytes that bind heavy chains of IgG antibodies.
Which receptor downregulates B cell activation? |
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Definition
Fc-gammaRIII(CD16), Fc-gammaRIIB(CD32), Fc-gammaRI(CD64)
Fc-gammaRIIB |
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Term
| What enzyme is required for isotype switching? |
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Definition
| AID (activation-induced deaminase) |
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Term
| Explain the alternative complement pathway. |
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Definition
| C3 is spontaneously cleaved to C3b, factor B binds to C3b, factor D cleaves factor B to C3bBb (C3 convertase), properdin stabilizes C3bBb, C3b binds to C3bBb to form C3bBbC3b (C5 convertase), C5 is cleaved to intitiate late steps |
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Term
| Explain the classical complement pathway. |
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Definition
Two IgG antibodies or one IgM antibody intiates binding of C1q to Fc portion of antibody, C1r cleaves C1s, C1s cleaves C4 and C2 to form C4b2a (C3 convertase), C3 binds and is cleaved to form C4b2aC3b (C5 convertase), C5 is cleaved to intitiate late steps
Classic pathway is amplified by alternative pathway. |
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Term
| Explain the lectin pathwway of complement activation. |
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Definition
| Binding of polysaccharides to mannose binding lectins (MBL) or ficolins, interaction with MASP1 or MASP2 which cleave C4 and C2, activation of classical complement pathway |
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Term
| What recognizes pneumococcal polysaccharide and activates the classical pathway by binding to C1q? |
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Definition
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Term
Explain the terminal complement pathway.
What inhibits formation of MAC? |
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Definition
C5b binds C6 and C7. C5bC6C7 is receptor for C8 binding. Poly C9 is added and complex forms pores (MAC complex).
S protein and CD59 |
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Term
| What is unregulated by Vitamin D to increase homing to the skin? |
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Definition
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Term
What is unregulated by Vitamin A (retinoic acid) to increase homing to the GI tract?
What do these receptors bind to? |
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Definition
alpha4-beta7 and CCR9
MadCam-1 and CCL25 |
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Term
| Describe transport of IgA across epithelial cells. |
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Definition
| IgA dimer is held by J chain. Transported to lumen by J chain binding to poly-Ig receptor via endocytosis. Poly-Ig receptor is cleaved and forms secretory component of secretory IgA. |
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Term
| What receptor is used to transport IgG? |
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Definition
| Neonatal Fc receptor (FcRn) |
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Term
| What inhibits TLR2 and TLR4? |
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Definition
| Surfactant protein (SP-A and SP-D) after binding PAMPS |
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Term
| What is expressed on dendritic cells which causes it to sample antigen or present antigen in the GI tract and respiratory tract? |
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Definition
CD103+ (present in GI and sample in respiratory)
CD11b+ (sample in GI and present in respiratory) |
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Term
| Name 2 inhibitory receptors. |
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Definition
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Term
| What route and dose leads to immunity versus tolerance? |
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Definition
Immunity - SQ, ID, low dose
Tolerance - oral, high dose |
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Term
| What is associated with HLA B-27 and HLA DR-B1? |
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Definition
HLA B-27 ankylosing spondylitis
HLA DR-B1 DM type 1, RA, SLE |
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Term
What regulates the alternative complement pathway?
The classical pathway? |
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Definition
Factor I, Factor H, MCP and DAF
C1inhibitor, DAF, CR1, C4-binding protein, and Factor I |
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Term
| What is the order of binding affinity of C1q for antibodies? |
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Definition
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Term
C5a is chemotactic for which cells?
C3a? |
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Definition
Neutrophils, eosinophils, monocytes and basophils
Eosinophils |
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Term
Describe kallikrein-kinin system activation?
What is involved in the positive feedback loop? |
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Definition
Factor XII (Hageman factor) binds endothelial surface and autoactivates to factor XIIa which cleaves prekallikrein to kallikrein, kininogen to bradykinin and cleaves XI to factor XIa (initiates intrinsic coagulation pathway)
Kallikrein cleaves and activates factor XI |
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Term
| What produces natural antibodies? |
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Definition
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