DrVirgo
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1. Histamine release from basophil or mast cell granules
A. Requires that these cells have IGe of only one antigenic specificity per cell
B. Is Ca2+ independent
C. Requires IGG antibody cross linking at the cell surface
D. Cannot occur in the absence of antigen-specific IgE
E. Follows IgE Fc receptor crosslinking
(Only ONE correct answer)
2. Neutrophils are important mediators of tissue damage in which types of hypersensitivities?
A. I and II
B. II and III
C III and IV
D. I and III
E. I and IV
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| doc179
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for q 1 A,B and D all look right....but is it D? ...still thinking abt q 2
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| skyhigh
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1 is E
2 is B
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| doc179
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I thught its FAB of IgE which cross links
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| msyamp
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skyhigh stands for her name. and Doc maest cells are triggered by all typs of allergen. and it is ca DEPENDENT NOT INDEPENDENT.IGe MAY NOT ALWAYS BE PRESENT TO TRIGGER.
Edited by msyamp on 02/06/06 - 12:37 PM
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| doc179
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I am wrong again
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| DrVirgo
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skyhigh is RIGHT!  good job.
1. E. Basophils and mast cells bind IgE via high affinity Fc receptors, so each cell has IgE of many different specificities on its surface.
msyamp is correct: Calcium is required for degranulation!!!
Many non-IgE triggers can cause granule release (e.g. C3a, and C5a)!!!
2. B. Neutrophils are triggered to release their granule contents by IgG complexes and activated complement fragments (C3b, C5a).
One example of this that I read about is in Rheumatiod Arthritis: IgM against IgG which
gets deposited in joints and has bound complement, then complement gets activated (Ca) and Neutrophils destroy bone. the a part of complement is inflammatory.
Does anyone know of any other examples of type II and III HS where neutrophils are involved? Please explain.. thanks.
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