Accessory cell function of liver granuloma macrophages of Schistosoma mansoni-infected mice.

In murine schistosomiasis mansoni, the inflammatory macrophage comprises 30% of the granuloma which forms around parasite eggs in the tissue. These granuloma macrophages (GR-Mphi) displayed dense Fc and C3 receptors, and about 50% expressed H-2I region-encoded determinants (Ia antigens). These GR-Mphi were able to effectively reconstitute the burro erythrocyte-specific immunoglobulin M and G antibody response of primed macrophage-depleted spleen cells. However, in contrast to splenic macrophages, GR-Mphi gave only minimal reconstitution of the primary immunoglobulin M response. The reconstitution of the T-cell proliferative response to L-glutamic60-L-alanine30-L-tyrosine10, an antigen under Ir gene control, was also observed when GR-Mphi were added to purified lymph node T-cells. The addition of a monoclonal antibody recognizing a determinant on the Ia complex effectively blocked L-glutamic60-L-alanine30-L-tyrosine10 presentation by GR-Mphi. These studies demonstrated that inflammatory GR-Mphi could function as antigen-presenting cells and that this accessory function was mediated by H-2I region gene products.