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-Mφ) displayed dense Fc and C3 receptors, and about 50% expressed H-2I region-encoded determinants (Ia antigens). These GR-Mφ 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-Mφ gave only minimal reconstitution of the primary immunoglobulin M response. The reconstitution of the T-cell proliferative response to L-glutamic⁶⁰-L-alanine³⁰-L-tryrosine¹⁰, and antigen under Ir gene control, was also observed when GR-Mφ 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-Mφ. These studies demonstrated that inflammatory GR-Mφ could function as antigen-presenting cells and that this accessory function was mediated by H-2I region gene products.