IMMUNOGLOBULINS
COMPLEMENT SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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C3a
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C3b
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C5a
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C5b
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Detailed explanation-1: -Assembly of the MAC (Fig. 18.12) is initiated when the complement protease C5 convertase cleaves C5 into C5a and C5b.
Detailed explanation-2: -C5b-C9, termed the complement membrane attack complex is responsible for the cytolytic function of complement, a potent mechanism contributing to innate defence against pathogens.
Detailed explanation-3: -MAC is generated through sequential assembly from the soluble complement proteins C5b, C6, C7, C8, and C9.
Detailed explanation-4: -C5 convertase cleaves C5 into two fragments: C5a and C5b. C5a is a potent anaphylatoxin that acts as a pro-inflammatory and chemotactic signal, promoting leucocyte activity and upregulation of immune responses [26–28]. C5b initiates MAC assembly on membranes in the immediate vicinity of activation.