Question

Which IgG subclasses can cause opsonization (macrophage binding)?

a) IgG1 and IgG3
b) IgG2 and IgG4
c) IgG1 and IgG2
d) IgG3 and IgG4

Answer 1

The IgG subclasses involved in opsonization, which enhances macrophage binding to pathogens for destruction, are IgG1 and IgG3.

Step-by-step explanation:

The IgG subclasses that can cause opsonization (macrophage binding) are IgG1 and IgG3. Opsonization is the enhancement of phagocytosis by the coating of pathogens with opsonins such as antibodies, which makes it easier for phagocytic cells like macrophages to bind to pathogens. Phagocytic cells such as macrophages, dendritic cells, and neutrophils have receptors for the Fc portion of IgG molecules and can thus bind to pathogens opsonized with these antibodies, facilitating their ingestion and destruction.