2,4-DINITROPHENYL RECEPTORS ON MOUSE THYMUS AND SPLEEN CELLS

A higher percentage of specific antigen-binding cells can be detected not only in normal CBA/J mouse spleen cell preparations (0.99%), but also in the normal thymus cell preparations (0.15%) with the use of [(125)I]2,4-dinitrophenyl-human IgG (DNP-HGG) as compared with most other antigens employed under similar conditions. The receptors on these cells are mainly specific for the DNP group as shown by the inhibition studies with DNP-lysine and the other DNP conjugates. In addition, it was shown by the inhibition studies with DNP-lysine that the thymus cells seem to have a lower avidity for DNP than the spleen cells. Preincubation of cell suspensions with antisera to immunoglobulins showed that the DNP-HGG antigen-binding cells in the thymus are inhibited predominantly with anti-µ-chain serum and the spleen cells with both anti-µ-chain and anti-γ-chain sera; both cell populations were also significantly inhibited with the antisera to κ-chains and Fab fragments. These data indicate that the nature of the receptor on the T cell differs from that on the majority of spleen cells.