EXPRESSION AND MODULATION OF C-3 RECEPTORS DURING EARLY T-CELL ONTOGENY

Using a corosette assay, optimal conditions were established for the detection of C3 receptors on T lymphocytes. E+-C3+ corosetting cells were demonstrated in four T-cell lines and six patients with E-rosetting acute lymphoblastic leukemia. Small numbers were detected in normal lymphoid tissues whereas thoracic duct lymph contained a large number of these cells. Following incubation of these tissues with thymic humoral factors, there was a decrease in corosetting cells with an increase in cells rosetting SRBC exclusively. Similar results were observed in vivo in a patient with severe combined immunodeficiency following a thymic epithelial cell transplant. Our data suggest that C3 receptor-bearing T lymphocytes occur early in T-cell ontogeny and can be modulated by thymic humoral factors. © 1979.