The nature and function of T-cell antigens.

T-lymphocytes differ antigenically from B-lymphocytes. In the present study attempts were made to determine the role of surface antigens of T-cells, in their migration in vivo and in their response to mitogens. Exposure of thymus cells to anti-H2 sera inhibits migration to the lymph nodes (LN) to a greater extent than to the spleen. Fab fragments of H-2 antisera had only a slight effect on lymphocyte migration, inhibiting the LN-seeking stream only slightly more than the spleen-seeking stream. The interaction of Con-A with carbohydrates on the cell-surface of lymphocytes inhibits preferentially their localization in LN. Studies on the migration of lymphocytes that had localized either in the LN or spleens of primary host indicate that Con-A does not eliminate LN-seeking cells, but rather inhibits their active localization in LN. The subpopulation of lymphocytes, in both thymus and spleen that responds to Con-A was found to possess a higher H-2 antigenicity and a lower Ly and theta-antigenicity than the cells responding to PHA. Spleen cells responding to low concentrations of PHA had a relatively high H-2 antigenicity, whereas thos responding to high concentrations of PHA had a low H-2 antigenicity. Exposure of thymus cells to H-2 antiserum alone markedly inhibited their response to Con-A. Similar treatment of spleen cells had only a weak inhibitory effect.