Proliferative and cytolytic reactivities of human lymphocytes fractionated on wheat germ agglutinin-Sepharose columns before or after alloactivation in mixed lymphocyte culture.

Human T-lymphocyte preparations from peripheral blood with either high- or low-avidity receptors for wheat germ agglutinin (WGA) were obtained by fractioned on WGA--Sepharose columns. Both fractions contained progenitors of alloreactive T cells, proliferating in mixed lymphocyte culture (MLC) and acting as effector cells in cell-mediated lympholysis (CML). Proliferation and CML activity of the two fractions were equal and similar to those of the unfractionated cells. However, when the lymphocytes were fractionated after 5 days' MLC, most of the proliferating and cytolytic cells were found in the lymphocyte fraction enriched in cells with high-avidity receptors for WGA. The reactivity of the fractions was correlated to their content of blast-transformed cells. The binding of MLC-activated lymphocytes to WGA was specific, since it was inhibited by the competitive hapten D-GlcNAc and no cells were retained on control columns charged with human serum albumin-Sepharose. B cells and monocytic cells were enriched in the fraction with low-avidity receptors for WGA. As indicated by experiments in which cells were mixed in different proportions, the low MLC-CML activity of the lymphocytes in the fraction with low-avidity WGA receptors was not caused by suppressor cells present in that fraction.