[Mechanism of suppression on cellular immunity in experimental brain tumor rats (author's transl)]

The mechanism of the suppression on the cellular immunity was analysed in experimental brain tumor rats. The tumor used in this experiment was a 3-methylcholanthrene induced fibrosarcoma. The tumor cell was inoculated into the caudate nucleus of the rats with a Hamilton microsyringe. When spleen cells from brain tumor rats were added to the PHA blastogenesis system, impairment of the normal lymphoproliferative response to the PHA was detected as early as on the third day and continued until the ninth day after inoculation. After the depletion of glass adherent cells, the residual cells from the spleen could not suppress the normal lymphoblastogenesis by the PHA. After the depletion of T cells by anti-T cell sera and complement, however, the residual cells from the spleen still suppressed the normal lymphoblastogenesis. Glass adherent cells were able to phagocyte the latex particles. From these findings, the suppressor cell responsible for the suppression of the normal lymphoblastogenesis by the PHA was considered to be macrophage and suppressor T cell did not play a role in the suppression of the PHA responses in this experimental model. The sera from brain tumor rats could not inhibit the proliferative responses of lymphocytes to PHA. Thus the possibility of the existence of suppressive factors in the sera was also negligible.