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Avian B Lymphocyte Subpopulations Origins and Functional Capacities

Studies on the development and function of the avian immune system were largely responsible for the initial recognition of the functional dichotomy of T and B lymphocytes (Glick et al. 1956, Cooper et al. 1966a). From subsequent studies in several species it has become increasingly evident that each of these major lymphocyte classes consists of physically and functionally different subpopulations. With specific reference to the B cell population, the detection of surface membrane markers including Ig (Raff 1970, Kincade et al. 1971, Rabellino & Grey 1971), Fc receptors (Basten et al. 1972), Ca receptors (Bianco et al. 1970) and a mouse specific B lymphocyte antigen (MBLA) (Ra2 et al. 1971) has led to further characterization of B cells. The presence of some of these receptors on only a proportion of B cells (Dukor et a]. 1971) is one indication for the possible existence of B cell subpopulations. Additional observations suggesting the existence of subpopulations include differences in migration pattern, tissue distribution and turnover rate of unprimed and antigen primed B lymphocytes (Strober & Dilley 1973), homing patterns of B cells ia Iym-