Permanent T-cell Anergy in Murine Toxoplasma gondii infection and the possible role of non-adherent cells and their products in the immunosuppression

Abstract

Lymphocyte blastogenesis experiments using T-cell mitogens, were performed on lymphocytes of mice chronically-infected with Toxoplasma gondii at different periods post infection (p.i.). The lymphoid cells demonstrated suppressed response to the mitogens from week one p.i. until week 17 p.i. Splenic lymphocytes from normal and infected mice were separated into adherent and non-adherent cell populations. Various combinations of these subpopulations were used in blastogenesis experiments. The non-adherent cell population was shown to be responsible for the immuno-suppression. In addition, supernatant from three day old cultures of infected mouse spleen cells was shown to depress the blastogenic response of normal mouse spleen cells to Concanavalin A. These results showed that infected non-adherent cells and/ or the production of soluble factors by these cells may play a role in the immuno-suppression of lymphocytes of Toxoplasma-infected mice to the mitogenic stimulations.