Antibody responses to experimental Brugia malayi infections in patas and rhesus monkeys.

Humoral antibody responses in experimental infections with Brugia malayi (subperiodic strain) were compared in two primate species. Erythrocebus patas and Macaca mulatta. Antibody responses were related to the infection protocol and the duration and magnitude of microfilaremia. Patas monkeys were uniformly susceptible to infection and characteristically exhibited prolonged microfilaremia; infections in Rhesus monkeys produced low and usually microfilaremia. Antibody, measured by enzyme linked immunosorbent assay with extracts of adult Brugia and microfilariae as antigens, declined at patency in Patas monkeys and there was an inverse relationship between serum antibody concentration and the number of circulating microfilariae. Rhesus monkeys generally had high, sustained antibody levels relative to Patas monkeys, but antibody levels were comparable in the two species when the numbers of circulating microfilariae were similar. By fluorescent antibody technique, antibodies reactive with somatic antigens of microfilariae were detected in all infected monkeys; antibodies reactive with the cuticle of infective larvae were also present in both primates and were consistently detected in monkeys receiving multiple infections. Antibodies (IgG, IgM) reactive with the sheath of microfilariae were detected only in certain Rhesus monkeys which were essentially amicrofilaremic and sera with antibodies specific for microfilarial sheath promoted in vitro microfilarial agglutination and leukocyte adherence.