Interactions between radioresistant T cells from plasmacytoma-bearing mice and radiosensitive T cells from normal mice leading to suppression

Spleens from BALB/c mice bearing the plasmacytoma SPQC 11 contain a population of T cells capable of suppressing the production of antibodies when cultured with normal BALB/c splenocytes, but not with splenocytes from nude BALB/c mice. Inhibition was characteristically the most effective at low suppressor cell numbers using unirradiated T cells. Maximum suppression occurred when a radiosensitive population of T cells from normal mice interacted with a population of radioresistant T cells from plasmacytoma-bearing animals. Accurate characterization of the suppressor T cell activity required testing over a wide range of suppressor/indicator cell ratios. Suppressor activity was eliminated by treatment with anti-Thy 1.2 plus complement, was radioresistant and present over a full range of doses when irradiated cells were used.