Relationship of T cells involved in cell-mediated immunity and antibody synthesis

Separable populations of activated thymus-derived lymphocytes identified in two assays for cell-mediated immunity to murine tumor allografts

The immune response of C57BL mice to a DBA/2 tumor allograft has been assessed in two assays of cell-mediated immunity, the in vitro lysis of (51)Cr-labeled target cells and the antigen-mediated inhibition of macrophage migration. Both assays were shown to be measuring a T-cell-mediated reaction. Three types of experiments suggested that distinct subpopulations of T cells mediate these reactions. The tissue distributions of these activities was distinctive; both activities were present in spleens from i.p. immunized mice, but only macrophage migration inhibition activity was found in the peripheral lymph nodes (PLN) of such mice. Adoptive transfer of immune spleen cells into irradiated syngeneic recipients revealed that while a substantial amount of migration inhibition activity could subsequently be found in PLN, cytotoxic activity was found predominantly in the spleens of these adoptive hosts. Velocity sedimentation analysis of immune cells 14 days after i.p. immunization indicated that while the majority of cytotoxic activity was associated with small and medium lymphocytes, the majority of migration inhibition activity was associated with medium and large lymphocytes. In addition, normal spleen cells were fractionated by velocity sedimentation immediately before allosensitization in vitro. Subsequent analysis of the sensitized fractions revealed that the activity profiles for cytotoxicity and macrophage migration inhibition were not coincident. The implications of these observations are discussed.

Lack of a correlation between cell-mediated immunity to the carrier and the carrier-hapten helper effect

The relationship between cell-mediated immunity to the carrier and the carrier-hapten helper effect was studied in the rat by using three forms of the carrier which differed in their capacity to induce carrier-specific delayed-type hypersensitivity. The three carriers were polymerized flagellin (POL), flagellin (FIN), and acetoacetylated flagellin (AFIN), which induced FIN-specific delayed-type hypersensitivity in the order AFIN > FIN > POL. Helper cells for the anti-DNP antibody responses to a range of DNP-FIN conjugates appeared to be almost inversely related to cell-mediated immunity to the carrier, being in the order POL > FIN =/> AFIN. These differences occurred whether the carriers were injected in saline or FCA, but were less pronounced with the heavily DNP-conjugated flagellins.