Effects of the IgG and IgM Immunoglobulins in Trypanosoma gambiense Infections in Mice

Abstract

The paper deals with the separation of IgG and IgM fractions in the serum of mice infected with T. gambiense and the immunological activities of both immunoglobulins. The agglutination reaction, formation of variant serotypes, and protection against infection are all associated with both IgG and IgM. However, while IgC is effective in the agglutination reaction, IgM is very effective in the formation of variant serotypes and in protecting the host from infection. Challenged animals immunized with crude homogenates of blood trypanosomes and their exoantigens showed protection against the homologous strains of trypanosomes (Weitz, 1960; Seed, 1963; Miller, 1965; Seed and Gam, 1966a). In addition passively transferred antiserum and immune plasma from immune donors were effective for variation of serotype (Osaki, 1959) and for complete protection against trypanosomes (Seed, 1963; Seed and Gam, 1966b). High protective ability of antiserum against infection was found particularly within 10 days after immunization (Takayanagi, 1971). Furthermore, protection against infection of T. gambiense was achieved by transfer of immune spleen cells, which are especially effective in early stage of immunization (Takayanagi et al., 1969). In the analysis of the agglutinating activity of the IgG and IgM fractions during an experimental infection, the agglutinating antibody was first found in the IgM fraction and then in both the IgM and IgG fractions later in the infection (Seed et al., 1969). These reports suggest that the immunoglobulins differ in their activities as regards agglutination of parasites, formation of variant serotypes, and protection against infection. This work aims to determine the biological activities of IgG and IgM fractions from mice immunized with Trypanosoma gambiense. MATERIALS AND METHODS