Amphotericin B modifications of peripheral blood lymphocyte and tonsil lymphocyte responses to concanavalin A

Peripheral blood lymphocytes (PBL) were shown previously to be activated to incorporate 3H-thymidine by concanavalin A (con A). Amphotericin B (Am B) was reported to be both immuno-enhancing and suppressive. We investigated the response of PBL and tonsil lymphocytes (TL) to con A in culture, and the effect of Am B on these responses. PBL were activated by con A as expected, and the magnitude of the response diminished as cell density increased. The responses of PBL usually were significantly enhanced by Am B at 2.5 or 5 μg/ml, but 10 μg Am B/ml significantly inhibited the con A response. TL had relatively high rates of spontaneous proliferation, but Am B was a potent inhibitor of this. TL responded to con A just as well as PBL, and Am B strongly inhibited these responses too. When TL were cultured with various doses of con A in the presence of 5 or 10 μg Am B/ml, the shape of the dose curves resembled those of PBL stimulated in the absence of Am B except that the incorporation of 3H-thymidine increased with increasing cell density. It was concluded that Am B at 2.5–5.0 μg/ml enhanced the response of PBL to con A and suppressed the response at 10 μg/ml. All doses of Am B inhibited both spontaneous proliferation and con A-induced proliferation in TL. In spite of this inhibition, the TL population responded to various doses of con A in the presence of Am B.