Opsonic index is the ratio of ?

Ans. is 'b' i.e.,Phagocytic activity of patient to phagocytic activity of normal individual The coating of an antigen or paicle (eg - infectious agent) by substances, such as antibodies, complement components and fibronectin facilitate phagocytosis. This is called opsonization.The substance which enhances phagocytosis (causing opsonization) is called opsonin. Two most impoant opsonins are antibodies (IgM, IgG) and complement (C3b).1gM is more effective than IgG in causing opsonization. Other opsonins are serum proteins like fibrinogen, mannose binding lectin and C-reactive proteins.The term 'Opsonic index' is defined as the ratio of of the phagocytic activity of patient's blood for a paicular bacterium to the phagocytic activity of blood of normal individual.It is used to study the progress of resistance during the course of the disease.