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16 Cards in this Set
- Front
- Back
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What makes B cells home to sites of chronic inflammation?
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-CXCR3-binds CXCL9 and 10 (?)(in Janeway: CXCR3 is expressed on pDCs which binds CXCL9/10, attracting them from the blood to the LN where there is an inflammatory response to pathogen)
-VLA4(alpha4:beta1)-binds VCAM-1(?)(in Janeway: VLA4 is expressed on activated T cells; this binds VCAM1, which is expressed at sites of inflammation) |
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What homes memory B cells to the bone marrow?
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B cells express:
-VLA4(alpha4:beta1)-binds VCAM1 -CXCR4-binds CXCL12 (expressed on sinusoidal endothelial cells of BM) |
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What is WHIM syndrome?
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-Warts, hypogamm, infections, and myelokethexis
-activating mutation in CXCR4 -low IgG -increased cells in the BM as they can't migrate to the periphery |
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What homes naive B cells to the Peyer's Patches?
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-integrin alpha4:beta7 which binds MadCAM-1 on the mucosa
-CXCR5 (?) |
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What homes memory B cells to mucosal-associated lymphoid tissue?
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IgA secreting memory B cells express:
-alpha4beta7-binds MadCAM1 -CCR9-binds CCL25 -CCR10-binds CCL28 |
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What homes naive B cells to the white pulp of the spleen and follicuar zone of the LN?
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-CXCR5-binds CXCL13
-CXCR4-binds CXCL12 -+/-CCR7-binds CCL 19 and 21 -LFA-1-binds ICAM -L-selectin (CD62L) binds addressins on HEVs |
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What are the activated T cells homing receptors and what do they bind on endothelial cells? (ie, leukocyte migration)?
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-E and P-selectin ligand (S-Lex) --> E and P selectin (weak adhesion)
-LFA-1 (beta2 integrin) --> ICAM-1 (stable binding) -VLA-4 (beta1 integrin) --> VCAM-1 (stable binding) -CXCR3-CXCL10 (leads to activation of integrins and chemokinesis) -CCR5-CCL4 (leads to activation of integrins and chemokinesis) |
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What are the naive T cells homing receptors and what do they bind (on endothelial cells or in the vacinity of the area they are homing to)? (ie, leukocyte migration)?
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- L-selectin --> MadCAM, GlyCAM, CD34
-CCR7-R --> binds CCL 19/21 (leads to adhesion of T cells to HEVs in LN) |
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What homes T cells to the gut?
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T Cell vs. Gut Ligand:
-alpha4:beta7 integrin and MadCAM-1 -CCR9 and CCL25 On intraepithelial lymphs (IELs)(a subset of T cells): -CD103 (alphaEbeta7) and E-cadherin |
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What are B1 integrins?
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-CD49a-f=alpha subunits
-CD29=B1 subunit -VLA-4 (=alpha4/beta1)(=CD49d/CD29) = binds VCAM-1; for gut assoc lymph tissue, monocyte gut homing, and neuronal homing (Multiple Sclerosis tmt) -VLA-5-binds fibronectin -VLA-6-binds laminin |
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What are B2 integrins?
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-CD11a-d=alpha subunit
-CD18=beta 2 subunit (deficient in LAD1) *important for T cell adhesion to endothelium -LFA-1 (=CD11a/CD18)(=alphaLbeta2) = binds ICAM-1 (leukocyte adhesion); binds ICAM-2/3 (T-cell:APC adhesion, T cell costim) -Mac-1 (=CD11b/CD18)(=CR3) = binds iC3b, ICAM-1, factor X, fibronectin; for leukocytes adhesion, phagocytosis, and cell matrix adhesion -CD11c/CD18 (=CR4) = binds iC3b |
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What are B4 integrins?
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-alpha4beta7, which binds MadCAM for gut homing
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What is the function of VCAM-1?
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-Ligand for beta1 integrin VLA-4 (=alpha4/beta1)(=CD49d/CD29)
-induced by IL-4 (allergic response) -neuronal homing (used for Multiple Sclerosis tmt) |
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What cytokines increases affinity of the integrins?
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-IL1 and TNF
-they're constitutively expressed though |
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What are the functions of selectins in general?
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-mediate rolling on the endothelium by quick repetitive binding and detatchment
-low affinity binding -TNF and IL1 from macrophages increase selectins 1-P-selectin (CD62P)-on endothelium, platelets, and in Weibel-Palade bodies 2-E-selectin (CD62E)-on endothelium 3-L-selectin (CD62L)-on leukocyte -all bind sialylated lewis X protein on ligands |
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What is the function of L-selectin?
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=aka, CD62L
-on naive T lymphocytes -homing receptor for naive T cells and DCs to LN -binds to PNAd (peripheral lymph node addressin) displayed on: (1) Gly-CAM1 in HEVs of LN, (2) MadCAM1 on GALT, (3) CD34, a proteoglycan on endothelial tissue and BM -L-selectin defiency = small LN, defective T cells/inflammation |
