Quantitative Measurement of Uptake of Alloantibody on Mouse Lymphocytes

Tritiated mouse alloantibodies were prepared by reaction of the gamma globulin fractions of antisera with DL ‐[3‐ 3 H]alanine‐ N ‐carboxy anhydride. The uptake of [ 3 H]alanylated allo‐antibody against H‐2, TL or θ on mouse cells proved specific. On the basis of the known specific radioactivity the number of alloantibody molecules taken up per mouse lymphocyte was calculated for the three alloantigenic systems. In comparisons of cell populations from lymph nodes and thymus it was shown that there is a striking difference in alloantigen representation, qualitative as well as quantitative, implying extensive changes in alloantigenic surface patterns during the maturation of thymocytes into lymphocytes.