Antigen-specific suppressor cells in hapten-specific carrier-determined tolerance.

Tolerance to the hapten 2,4-dinitrophenyl (DNP) induced by the injection of DNP coupled to isologous IgG (carrier-determined tolerance) is associated with a receptor blockade of antigen-binding lymphocytes. In the present study, hapten-specific suppressor cells were detected in the spleens of mice made tolerant by intravenous injection of 20 microgram DNP-IgG. When spleen cells from mice rendered tolerant to DNP were co-cultured with normal spleen cells in Marbrook cultures, the response to DNP-Ficoll was suppressed, while the response to sheep red blood cells was not altered. Depletion of T cells from these spleens restored the normal anti-DNP response. The suppressor cells were not detectable in the spleen lymphocyte population of mice in the early stages of tolerance but were present on day 7 after injection of tolerogen, and disappeared by day 14. Mice injected with larger doses of 1 mg or four weekly doses of 200 microgram DNP-IgG did not have detectable suppressor cells. Thus, it appears that a short-lived suppressor T cell is generated in carrier-determined tolerance. This cell most likely plays a minor role in the mechanism of carrier-determined tolerance and may be associated with the receptor blockade which is seen early in tolerance.