Solubilization and partial purification of lymphocyte specific antigens in the chicken

Four different lymphocyte antigens were solubilized from chickens homozygous at the B locus. The antigens were identified by immunoelectrophoresis with rabbit anti‐lymphocyte sera. 1. A bursa‐specific cell surface antigen was extracted with 3 M potassium chloride and partially purified. The antigen was excluded from Sephadex G‐200 gels, was heat labile and was a potent immunogen. The antigen could be detected on all bursa cells by immunofluorescence but not on thymus, spleen or blood lymphocytes. The findings do not exclude, however, the possibility that a small number of lymphocytes (e.g. plasma cells) possess the antigen. 2. A thymus‐specific antigen was obtained by papain treatment of thymus cells. It migrated cathodically in immunoelectrophoresis. 3. A surface antigen which was specific for lymphocytes from both central lymphoid organs (thymus and bursa) was solubilized by pestle homogenization. 4. A fourth lymphocyte surface antigen was present on lymphocytes from blood, spleen, bursa and thymus. It was best solubilized by 3 M potassium chloride extraction and did not migrate under the conditions of immunoelectrophoresis. Studies did not reveal a stable antigenic marker with specificity for thymus or bursa cells and their progeny in the peripheral lymphocyte pool.