Differential involvement of non-specific suppressor T cells in two lethal murine malaria infections.

The suppression of the contact sensitivity of oxazolone in murine malaria is shown to be mediated by non-specific T suppressor cells, but to a different extent in infection caused by two different species of parasite. Depletion of T suppressor cells in vivo and/or anti-Thy 1.2 treatment in vitro indicated that in mice infected with P. berghei the suppressor effect was largely mediated by T cells. By contrast, in mice infected with a lethal strain of P. yoelii it was only partly due to T cells; B suppressor cells and/or macrophages may also be involved. However, depletion of T suppressor cells in vivo had no effect on the course of the parasitaemia or on the survival time. Therefore, we postulate that this kind of non-specific immunosuppression cannot be regarded as a major cause of lethality.