Antigenic properties of lymph-node cells responding to allogeneic lymphocytes and to various concentrations of lectins

The aim of the present study was to characterize the antigenic properties of T-lymphocytes responding in mixed lymphocyte reactions and of those stimulated by various concentrations of concanavalin A (Con A) and phytohaemagglutinin (PHA). Lymph-node cells were exposed, in the presence of C', to alloantisera against H-2, Thy-1 and Ly-1.1 antigens or to rabbit anti-mouse IgG serum. The responsiveness of the residual cells to the various stimuli was determined. Lymph-node cells responding to allogeneic stimuli were found to be T cells possessing high concentrations of H-2, Thy-1 and Ly-1.1 antigens. Cells responding to various concentrations of Con A seemed to have a higher concentration of H-2, Thy-1 and Ly-1.1, as compared with cells responding to corresponding concentrations of PHA. Cells responding to optimal concentrations of Con A and PHA had a lower concentration of H-2 and Thy-1 antigenicity than those responding to either sub-optimal or supra-optimal doses of the respective lectins. Cells responding to supra-optimal concentrations of lectins had the highest concentration of Ly-1.1. The Ly-1.1 antigenicity of the cells responding to optimal or suboptimal lectin concentrations decreased in parallel with the decrease of the lectin concentration to which they responded. It is concluded that antigenic markers can be used to distinguish not only between subsets of T cells responding to various stimuli, but also between T cells responding to various intensities of these stimuli.