INTERLEUKIN-2 INDUCES DEVELOPMENT OF DENDRITIC CELLS FROM CORD-BLOOD CD34(+) CELLS

Dendritic cells (DC) have been shown to develop, along a myeloid or ly mphoid lineage of differentiation propagated from bone marrow or early thymic precursor cells with hematopoietic cytokines. In our study, we have induced growth and differentiation of DC from cord blood CD34(+) cells initiated in interleukin-2 (IL-2) alone or in IL-2 + stem cell factor (SCP) + tumor necrosis factor alpha (TNF-alpha)-supplemented me dium and cultured with IL-2 or IL-2 + SCF for 28-35 days, Dendritic mo rphology and antigenic phenotype of DC grown with IL-2 were characteri stic for DC cultured in the presence of granulocyte-macrophage colony- stimulating factor (GM-CSF). Growth and differentiation of DC was foll owed by an increase in expression of MHC II and co-stimulating molecul es CD80 and CD86. We have also shown the expression of the IL-2 recept or (IL-2R) gamma-chain in CD34(+) cells after 2-3 days of culture with IL-2 alone. The co-expression of the IL-2R alpha, beta, and gamma sub units in both DC cultured with IL-2- or GM-CSF-containing cocktail of cytokines was also shown. The time curve for induction of IL-2R demons trated low levels of subunit expression at the beginning of culture, T he number of CD1a cells co-expressing CD25, CD122 and CD gamma increas ed to about 24-693 and to 78-95% after 21 and 28-35 days, respectively . Development of natural killer cells was shown along with DC. The pro portion of CD56(+) cells and cytotoxicity increased in a time-dependen t manner.