Trichinella spiralis: Immunologic response to infection in mice

Abstract

Serum IgG 1, IgG 2, IgM, and IgA levels were measured by radial immunodiffusion in C57B1 mice after infection with 200 Trichinella larvae. IgG 1 concentrations increased 2- to 5-fold during the second week of infection; IgA and IgG 2 levels showed little consistent change; IgM concentrations increased from the second week through the fourth week of infection. Similar changes in serum immunoglobulin levels, with the exception of IgM, were found in ICR mice infected with Trichinella. An increase in IgG 1-containing cells relative to cells containing immunoglobulins of other classes was observed in the immunocyte populations of the spleens, mesenteric lymph nodes, and Peyer's patches of mice hyperinfected with Trichinella. The immunocyte population of the intestinal mucosa showed a relative increase in IgM- and IgG 1-containing cells during the second week after primary infection. Antibody in the four immunoglobulin classes was measured by the indirect fluorescent antibody technique using frozen sections of muscle larvae as antigens. By day 15 of infection antibody was detected in all immunoglobulin classes. Antibodies in IgG 1 and IgG 2 exhibited specificity for the stichosome cells and cuticle; antibodies in IgA and IgM showed specificity principally for membranes of the larvae. Antibody in the content of the small intestine was detected during the second week of infection. These antibodies were predominantly in IgA. Antigen ( Trichinella extract)-sensitive cells in spleen, mesenteric lymph node and Peyer's patches of Trichinella-infected mice were detected by incorporation of tritiated thymidine in cell cultures. The cells were detected in the spleen during the first week of infection and by the second week in the other lymphoid tissues. Transfer of spleen cells or lymph node cells from Trichinella-infected C57B1 mice to uninfected C57B1 mice induced an accelerated, humoral antibody response to Trichinella antigens in the recipient mice after inoculation of the mice with infective Trichinella larvae.