Enhancing and inhibiting effects of spleen cells from tumour-bearing mice on growth of virus-induced primary sarcoma.

The effects of adoptive transfer of spleen cells from tumour-bearing mice on the growth of Moloney murine sarcoma virus (M-MuSV)-induced primary tumours in BALB/c mice were studied. The effects were in 2 directions, depending on the time of lymphocyte inoculation; when spleen cells from tumuor-bearing mice 12 days after M-MuSV inoculation were inoculated into recipient mice before M-MuSV inoculation, the appearance of tumours was significantly delayed and their incidence was reduced, whereas when these lymphocytes were inoculated after the development of tumours in recipient mice, tumour growth was significantly enhanced. The data indicated that these inhibiting and enhancing effects were mediated mainly by T cells. The mechanisms of the parodoxical effects were investigated.