Restriction of Surface Immunoglobulin Determinants to Lymphocytes of the Plasma Cell Line

Abstract

With widespread acceptance of selective theories for antibody formation, intense interest has focused on the identification and characterization of antigen recognition sites on immunocompetent cells. Immunoglobulin determinants have been demonstrated on the surface of lymphoid cells by a variety of techniques (1–5); these determinants have been related to the antigen-binding properties of the cells (5–7). Since the relative proportion of lymphocytes bearing detectable surface Ig determinants is lowest in the thymus, it has been suggested that these cells belong exclusively to the thymus-independent population of lymphocytes (8, 9). This hypothesis can be readily tested in the chicken because of the feasibility of eliminating selectively either the thymus-dependent or the plasma cell lines of differentiation (10). In this report evidence is presented that heavy chain determinants of immunoglobulins which are detectable on a large percentage of lymphocytes in normal chickens are absent from the lymphocytes of birds in which the plasma cell line has been selectively eliminated.