Regulation of immune responses in SJL and F1 hybrid mice by gamma-irradiated syngeneic lymphoma cells.

Syngeneic mixed lymphocyte-stimulating la+ lymphomas of SJL mice [reticulum cell sarcoma(s) (RCS)] were found to modulate immune responses in vivo. Simultaneous injection of 2 X 10(7) gamma-irradiated or glutaraldehyde-fixed RCS cells with the antigen sheep red blood cells (SRBC) or 2,4,6-trinitrophenol (TNP)-Ficoll markedly suppressed the subsequent plaque-forming cell response in the spleen. The suppression of the anti-SRBC response was prevented by pretreatment of the mice with cyclophosphamide, whereas the suppression of the anti-TNP-Ficoll response was not affected. RCS injection induced high interferon serum titers within 24 hours after injection, which were not prevented by pretreatment with cyclophosphamide. Injection of gamma-irradiated RCS cells (gamma-RCS) or RCS cell extract 2 days prior to antigen enhanced the anti-SRBC but markedly suppressed the anti- TNP-Ficoll response. Injection of RCS both on day -2 and day 0 enhanced the anti-SRBC response. SJL mice 8-9 months of age showed much less or no suppression when gamma-RCS cells were injected on day 0. Certain F1 hybrids of SJL also showed the gamma-RCS-induced suppression of the anti-SRBC response. Suppression was seen in SJL X BALB.B but not in SJL X BALB/c mice and in SJL X A.TH but not in SJL X A.TL mice, suggesting an I-region effect. F1 hybrids of SJL by B10 background mice showed no significant suppression. Enhancement of the anti-SRBC response by prior injection of gamma-RCS was seen in all F1 hybrid mice examined.