Thymic hormone modulation of CD38 (T10) antigen on human cord blood lymphocytes

We studied the in vitro effect of three different thymic factors on the expression of CD38 (T10) antigen on cord T-lymphoid cell surface. The results showed that cord mononuclear cell populations contain variable percentages of CD38+ cells. The CD38 molecule was expressed on cord T and B lymphocyte and monocyte surfaces. Incubation with thymic agents induced a significant increases in the CD38+ cell percentage only in the samples with low CD38 antigen expression, and this modulation was mainly attributable to the T-cell subset. The effect seems to be specific and not correlated with the known high spontaneous DNA synthesis rate of cord mononuclear cells.