Suppression of Humoral and Delayed Hypersensitivity Responses by Distinct T Cell Subpopulations

Immunization of mice with a supraoptimal dose of sheep red blood cells (SRBC) results in splenic T cell populations capable of specifically suppressing recipients' plaque forming cell (PFC) and delayed-type hypersensitivity (DTH) responses to SRBC when tested in an adoptive transfer system. By localization on discontinuous bovine serum albumin (BSA) gradients and relative sensitivity to Cytoxan, two distinct T cell subpopulations suppressing DTH reactivity were identified. One population could not be distinguished from T cells capable of inhibiting direct and indirect PFC responses. However, another population appeared quite distinct and capable of inhibiting DTH, but not PFC responses.