The Role of Maternal Antibody and Complement in Protection of Young Mice Against Infection with Trypanosoma Gambiense.

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There are at least two routes of antibody transmittance from hyperimmune females into fetal circulation. The one is placental and yolk sac route during pregnancy, the other is colostral route after birth. Antibodies which move through the placenta or yolk sac or colostral route are IgG molecules. By suckling colostra from hyperimmune mother, agglutinin activity in young mouse serum increased rapidly. Young mice with colostral IgG antibody showed protection against trypanosomes. So, colostral IgG antibody is the main component which is responsible for clearance of pathogens. I try to inquire further into the mechanism by which host immune protection is facilitated. Aggregated trypanosome masses formed in equivalence area without complement are readily dissociated by complement.Complement-mediated dissociation of the clumped trypanosomes in the equivalence area released approximately fifty percent of previous bound surface antigens. These antigens are capable of binding again to new IgG antibody. Experiments indicate that complement deposition alters bivalent IgG antibody in the immune complex into a univalent one. Such event in the presence of complement is of great advantage to the infected host in killing pathogens in vivo, as it allows more antibodies to attach to surface antigens and subsequently initiate complement activity. Complement can fulfill the dissociating function whether it is activated by the classical or by the alternative pathway.