Question

The effector functions of complement can be activated through three pathways. The classical pathway is activated by antibodies binding to antigens. The mannan-binding pathway is initiated by binding of a serum lectin, the mannan-binding lectin, to mannose-containing carbohydrates on bacteria or viruses. The alternative pathway can be initiated when a spontaneously activated complement component binds to the surface of a pathogen. In the classical pathway, complement is activated when C1 binds to a portion of the immunoglobulin molecule known as what?

Fab
F(ab')2
Fv
Fc
V domain

Answer 1

In the classical complement pathway, C1 component activation is triggered when the C1 molecule binds to the Fc portion of an antibody that has recognized an antigen. Option D.

Step-by-step explanation:

In the classical pathway of the complement system, complement activation occurs when the complement component C1 binds to the Fc portion of an immunoglobulin molecule that has attached itself to an antigen on the surface of a pathogen.

This process leads to a cascade of events including the tagging of the pathogen for phagocytosis (opsonization), recruitment of phagocytes, and eventually, the creation of the membrane attack complex (MAC) that forms pores in the microbial cell envelope or cell wall leading to the lysis of the pathogen.

So Option D,