T Cell Regulation of Pokeweed Mitogen-induced Polyclonal Immunoglobulin Production in Mice : Role of Virus-replicating T Cells in Suppression

Abstract

Role of virus-replicating T cells in the regulation of pokeweed mitogen (PWM)-induced polyclonal immunoglobulin (Ig) production was studied in mice. A large number of cells which can replicate vesicular stomatitis virus (VSV) were generated in PWM-stimulated cultures of spleen cells. The optimal dose of PWM for the generation of VSV-replicating cells was within the range 25 to 50μg/ml, which were also shown to be optimal for the induction of suppressor T cells. In spleen cell cultures, helper activity was attributed not only to Lyt-1^+2^- but also to Lyt-1^+2^+ T cells and both the precursor and effector suppressor T cells were found to be Lyt-1^-2^+. The VSV-replicating cells in this system were shown to be Thy-1^+ and Lyt-1^+2^-. These cells, however, were unlikely to be helper T cells, but may be a subset of T cells involved in suppression. Thus, inoculation of VSV into the PWM-stimulated cultures of spleen cells resulted in the marked augmentation of Ig production, and the suppressive activity of T cells which had been precultured with a high dose of PWM was abolished by the infection with this virus while the helper activity remained unaffected. Further, it was shown that although the Lyt-1^-2^+ T cell subset could be directly stimulated by PWM to generate suppressor cells, the presence of Lyt-1^+2^- cells in the culture markedly enhanced the generation of Lyt-1^-2^+ suppressor cells.