Effects of functionally-distinct T-cell subsets on the maturation of null cells in man.

We have found that the 'null' cell population (negative for surface immunoglobulin and for E-rosette formation) includes cells which can develop surface immunoglobulin and secrete immunoglobulin in culture. The apparent 'maturation' of these null cells to immunoglobulin-secreting B cells was enhanced by T cells and may require T cells. T-cell subsets shown previously to have a helper effect on immunoglobulin secretion by peripheral blood B cells accelerated this maturation process, whereas subsets without helper effects on peripheral blood B cells did not.