IMMUNOPHENOTYPIC AND FUNCTIONAL-CHARACTERISTICS OF HEMATOPOIETIC-CELLS FROM HUMAN CORD-BLOOD

Cord blood (CB) as a new source for bone marrow transplantation repres ents advantageous features concerning stem cell and leucocyte compartm ents and function. We attempted to get more information about the phen otypes and function of CB cells by investigating their cell surface ma rkers and also the production of IL-2, IFN-gamma and IL-6 by mitogen a nd alloantigen stimulation. The CB cells were characterized by a low p roportion of CD3(+) T cells, CD4(+) T subpopulation, activated T cells and CD3(+)CD16/CD56(+) cytotoxic cells, suggesting reduced graft vers us host potential. The significant increase of CD19/CD3 double positiv e cells and decrease of CD19/HLA-DR double positive mature B cells ref lect that immature B cells exist in CB. In the functional studies, a 2 7- and 5-fold reduction was observed in the production of IFN-gamma by CB cells stimulated with PHA and allogeneic cells, respectively. The production of IL-2 in PHA-stimulated CB cells also showed a 50% determ ination. Decrease in the production of these cytokines by CB cells is supported by the decline of the proportion of CD3(+) T cells. However, an increase was observed in the production of IL-6 by CB cells stimul ated with allogeneic cells as compared with the controls. These result s suggest a difference in the functional activity of the T helper cell subsets between the CB and peripheral blood and/or differences in the functional maturity of T helper cell subsets and B cells in these com partments.