IgG response of rats to the excretory-secretory products of Litomosoides carinii.

The nature of antibody responses to the excretory-secretory (ES) products of adult worms and microfilariae (Mf) of Litomosoides carinii in albino rats and their possible role in protection have been studied. Rats were immunized with ES products derived from in vitro incubation of adults or Mf. The sera from these rats promoted neutrophil-mediated killing of Mf in vitro. The antibody responsible for the cytocidal activity was identified as IgG isotype. Indirect fluorescent antibody test showed the presence of IgG on the surface of Mf incubated in either of the immune sera. The immune sera were effective in clearing the circulating Mf in Mastomys natalensis, indicating the protective nature of the antibody. Thus, L. carinii in culture liberate functional antigens that seem to have protective potential.