Inhibition of a primary DNA-synthesis response by trinitrobenzosulfonate (TNBS)-activated suppressor cells; characterization of the inhibitory cells.

Repeated intravenous injections of high doses of trinitrobenzosulfonate (TNBS) or dinitrobenzosulfonate (DNBS) activate suppressor cells which inhibit the in vivo activation of a primary DNA synthesis response against trinitrochlorobenzene (TNCB) and dinitrochlorobenzene (DNCB), respectively, almost completely and the delayed type hypersensitivity (DH) response only partially. When tested on the DNA-synthesis response, the suppressor cells show excellent specificity with little cross reactivity of TNBS (or DNBS) induced suppressor cells for DNCB- (or TNCB-) specific responses. TNBS- and DNBS-specific suppressor activity is found in spleen cells, mesenteric lymph nodes and peripheral lymph nodes. The activation of suppressor cells is resistant to the early effects of adult thymectomy (ATx), but sensitive to pretreatment with cyclophosphamide (CyP). The suppressor cells are not simply haptenated cells. They need several days for their activation and are inactivated by incubation for 30 minutes at 56 degrees C or by 2,000 R irradiation. Attempts to obtain soluble suppressor factors by in vitro incubation or extraction of these suppressor cells failed.