RESUMEN
The effect of Trichinella spiralis in different phases of infection on transplantation immunity, the ability of lymphocytes to induce graft-versus-host reaction, on antibody and plaque-forming cell production was studied. In certain phases of Trichinella spiralis beginhing from the first days of infection and during 40 days significant suppression of transplantation immunity was observed. Thus, on the 24th day of infection skin allograft necrosis occurred much later (26.2 days) as compared with non-infected mice (12.5 days). The spleen cells of C57BL/6j mice infected with Trichinella spiralis on the 22, 29, 36, 42, 56, 72 days either induced slight graft-versus-host reaction in (CBA X C57B1/6j) F1 hybrid mice or did not induce it at all (42nd day of infection). The amount of antibody forming cells in Trichinella-infected mice significantly decreased on the 20, 25, 47, 55th days of infection. Hemagglutinin production to sheep red blood cells was significantly inhibited on the 25th day of Trichinella spiralis infection. The concept of immunodepressors being released from helminths is briefly discussed.