Abstract
The syndrome of severe combined immunodeficiency disease (SCID) represents a group of congenital lethal disorders, characterized by defects of both T- and B-cell systems (Hitzig et al., 1971; Giblett et al., 1972; Gatti et al., 1969; Pyke et al., 1975; Hong et al., 1978; Gelfand et al., 1977; Pahwa et al., 1979). Although the ultimate immunological expression of these disorders is quite similar, the defect of lymphoid development may vary. Studies using thymic extracts, thymic epithelial monolayers, and thymic hormones have revealed that the differentiation of precursor cells may be abnormal in SCID (Touraine et al., 1974; Pahwa et al., 1977, 1979). Most of the previously reported studies on T-lymphocyte differentiation have employed mainly rosette formation with SRBC (E-rosettes) as a differentiation marker for T cells. In this communication, we have investigated the differentiation of T-cell surface antigens using mouse monoclonal antibodies on two patients’ blood and bone marrow lymphocytes using cultured thymic epithelial monolayers and thymosin fraction 5 (TF5) as inducing agents.