ANTIGEN-INDUCED CHANGES IN LYMPHOID CELL HISTONES : II. Regional Lymph Nodes.

The nuclear histones of control and antigen-affected lymphocytes and thymocytes were measured in terms of their intensity of staining with ammoniacal-silver (A-S) and alkaline fast green (FG). Subcutaneous injection of full strength and doubly concentrated tetanus toxoid into the upper forelimb was followed by an acute decrease in the intensity of the FG and A-S staining of the thymocyte nuclear histones. Such changes in staining were delayed in the nuclear histones of the regional axillary lymph nodes. In contrast, the injection of a 1:100 dilution of tetanus toxoid caused an acute decrease in staining of the nuclei of the regional lymph node lymphocytes but only minimal changes in the thymocytes. An acute decrease in staining of the lymph node lymphocytes also occurred when heterologous serum proteins were used as the antigen. Prior administration of cortisone was found to inhibit the antigen-induced changes in the staining of lymphocyte nuclear histones. No such inhibitions occurred after the administration of saline solution. The findings suggest that the nuclear histones play a significant role in the immunological competence of lymphoid cells. However, additional studies are needed to define the biochemical basis of the observed changes as well as the mechanisms whereby antigen-induced changes in nuclear histones participate in the complex cellular and serological alterations which are evoked by antigens, viz. plasma cell formation and antibody synthesis.