Soluble Factors in Tolerance and Contact Sensitivity to 2,4-Dinitrofluorobenzene in Mice: I. Suppression of Contact Sensitivity by Soluble Suppressor Factor Released in Vitro by Lymph Node Cell Populations Containing Specific Suppressor Cells

Tolerance to 2,4-dinitrofluorobenzene (DNFB) contact sensitivity is in part mediated by suppressor thymus-derived cells (T cells) which are induced by pretreatment with the hapten 2,4-dinitrobenzenesulfonate. If lymph node cell suspensions containing suppressor cells are cultured in vitro, soluble suppressor factor (SSF) is released into the supernatant. When DNFB-immune lymph node cells are incubated with SSF, their ability to transfer contact sensitivity to normal recipients is suppressed. In order for SSF to be produced and/or released, it was necessary to paint the tolerant animals with DNFB 16 to 20 hr before the lymph node cells were cultured, suggesting that SSF was made in response to antigen stimulation. Specificity studies showed that SSF was both antigen specific and strain specific in its action. In addition, it was found that SSF could be absorbed by 2,4-dinitrophenyl-keyhold limpet hemocyanin (DNP-KLH) (not by KLH alone) and by anti-H-2 antibodies but not by trinitrophenyl-KLH, anti-immunoglobulin, or anti-DNP antibodies. Taken together, these results indicate that SSF is a product of the major histocompatibility complex which, although not antibody, has affinity and specificity for the hapten DNP. Furthermore, in order for SSF to suppress DNFB sensitivity, identity is required among genes in the H-2 complex between the donor of SSF and the immune lymph node cells.