T and B lymphocytes in the regulation of delayed hypersensitivity.

A correlation was demonstrated between the transient nature of a) delayed intradermal responses of guinea pigs sensitized to hen egg albumin in incomplete Freund's adjuvant and b) the proliferative response of sensitized lymphocytes to the specific antigen. Spleen cells from sensitized animals suppressed the proliferative response of lymph node cells to specific antigen. This suppression was dependent on the dose of spleen cells and the time of their removal after sensitization. Thymus cells were suppressive to a lesser extent, and their activity was not correlated with the time of removal after sensitization. Separation of spleen and thymus cells into T and B populations indicated that the B cell was the major suppressor cell in the spleen, while the T cell in the thymus had a similar but less pronounced action.