IMMUNOGLOBULINS
CLASSICAL ALTERNATE AND LECTIN PATHWAYS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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C1q
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C1r
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C1s
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C4
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Detailed explanation-1: -In addition to binding IgG and IgM, C1q recognizes a great variety of ligands, which are highly diverse in their overall structure and charge pattern.
Detailed explanation-2: -C1 binds IgM through widely spread C1q-collagen helices, with C1r proteases pointing outward and C1s bending downward and interacting with surface-attached C4b, which further interacts with the adjacent IgM-Fab2 and globular C1q-recognition unit.
Detailed explanation-3: -The complement system is a key part of the innate immune system and plays an important role in the clearance of pathogens and apoptotic cells upon its activation. It is well known that both IgG and IgM can activate complement via the classical pathway by binding of C1q to the Fc regions of these immunoglobulins.