Effect of anti-beta2-microglobulin on antigen and allogeneic lymphocyte-induced proliferation of human lymphocytes

The effect of anti-beta2-microglobulin (beta2m) on the mixed lymphocyte reaction (MLR), and an antigen-induced proliferative response was studied. Anti-beta2m IgG and Fab' fragments completely inhibited the MLR. Preincubation of stimulator or responder cells with anti-beta2m suggested that the major effect of anti-beta2m may be on the responder cell population. A clear-cut effect on responder cells was demonstrated by showing that anti-beta2m completely inhibited a MLR in which the stimulator population was a beta2m negative lymphoblastoid cell line. Anti-beta2m also inhibited PPD-induced proliferation of sensitized lymphocytes. The kinetics of this inhibition indicated that anti-beta2m added within the first 18 hr of stimulation was effective in inhibiting the proliferative response. These data are discussed in light of the hypothesis that beta2m may be a subunit of an antigen receptor on T cells.