Isolation of suppressor T lymphocytes adherent to histamine conjugated albumin and their role in suppression of IgG response to SRBC

Antigen-specific immunosuppression to sheep red blood cells (SRBC) in BALB/c mice was induced by repetitive injection of high doses of soluble components derived from a hypotonic lysis of SRBC. This form of unresponsiveness induced both IgM and IgG suppression. The IgG, but not the IgM suppression, was stable and persisted in an adoptive transfer. The transferred IgG unresposiveness could be terminated by the removal of a cell population that bound to histamine-rabbit serum albumin-Sepharose (HRS). Such a population could actively suppress normal immunocytes as well as immunocytes in which suppression was eliminated by removal of cells adherent to HRS. The suppressor population shows immunospecificity typical of T cells and its suppressive activity is completely abrogated by anti-θ antibody-induced lysis. Furthermore, we demonstrated that the cell, by virtue of separation on insolubilized histamine columns, has surface characteristics different from the helper T memory cell. Functional B and T immunocytes were found in the SRBC-suppressed mice. We therefore conclude that this type of antigen-induced immunosuppression is maintained solely through an active T cell-mediated suppression.