Studies on Alteration in Antibody Level of Filarious Host Following Diethylcarbamazine Treatment

Sharp fall in antibody level of Mastomys natalensis infected with Litomosoides carinii occurred following treatment with diethylcarbamazine (DEC). Though reduced haemagglutinin titre returned to pretreatment level within 30 days, precipitin titre which disappeared totally did not show a come-back even upto day 50. The decrease in the levels appear to be due to increased consumption of antibody (more of IgG than IgM type) in reaction with dead and degenerated microfilarial products (antigens). This was substantiated by the facts that DEC did not alter antibody level specific to BSA or adult male parasites (thus lacking microfilariae). The concept of neutralisation of antibody in reaction with sudden massively released microfilarial products could also be established from experiments in which sharp fall in antibody occurred following administration of large amount (9 mg) of microfilarial (mf) antigen proteins in infected animals. It is concluded that fall in antibody titre following DEC therapy is due to quick death of microfilariae in large numbers and the drug has no direct effect on host\u27s immune mechanisms