FC RECEPTORS ON CHICKEN LYMPHOCYTES-T

Agammaglobulinemic chickens were used as a source of T lymphocytes, uncontaminated by B lymphocytes, to study subpopulations of thymus-derived lymphocytes. A subpopulation of T lymphocytes (TG lymphocytes) possessing IgG receptors and lacking membrane immunoglobulins was identified in these chickens. The IgG receptor specifically bound the Fc but not the Fab portion of chicken IgG. TG cells were not macrophages and did not adhere to plastic or nylon surfaces. The proportion of TG lymphocytes in the spleen (mean 14%, range 9-18%) was higher than that in the thymus or peripheral blood. The number of TG lymphocytes in the spleens increased after immunization, suggesting that primed T cells may possess IgG-Fc receptors. TG and T cells lacking the IgG-Fc receptor (TG - lymphocytes) were obtained from the Spleens of carrier primed agammaglobulinemic chickens and assayed for helper activity by an adoptive transfer method. It was shown that TG staggered- lymphocytes, but not TG lymphocytes, were capable of providing helper activity for hapten primed B lymphocytes in anti-hapten antibody responses. © 1978.