All of the following molecules are opsonins that facilitate efficient phagocytosis of microbes by neutrophils and macrophages EXCEPT:
A)C3b
B)C5a
C)C-reactive protein
D)IgG
E)Mannose-binding lectin

Question

Quizplus · Accepted Answer

C5a is a peptide released after cleavage of C5 protein during the complement cascade.It stimulates the influx of neutrophils to the site of infection,thus acting as a chemoattractant,not as an opsonin.C3b (covalently bound to microbes on which complement activation has taken place)and IgG bound to antigen,are particularly potent opsonins,because phagocytes have receptors for both C3b and the Fc region of IgG.C-reactive protein and mannose-binding lectin also can coat microbes and be recognized by phagocyte receptors;thus they serve as opsonins.

All of the Following Molecules Are Opsonins That Facilitate Efficient