T Cell Expansion From Umbilical Cord Blood Without Thymic Stroma Cells After Stimulation With Scf, Il-7, and Il-2

We analyzed in vitro expansion and differentiation of t progenitor cells from umbilical cord blood in the absence of thymic epithelium. the expansion setup is performed in the presence of scf, il-7 , and il -2 with autologous serum .using cbmcs as initial source , we compared the growth kinetics of several cell populations in either whole cbmc or cd34+ -enriched-, as well as in cd3cd4cd8-depleted expansion assays by facs analysis. after 11 days of culture, cell increase values were about 7 fold for cd3+, 6 fold for cd3+cd4+, 7 fold for cd3+cd8+, 4fold for cd3+cd56, 6fold for cd56+, and 0.2 fold for cd34+. we characterized the developmental state of these cell populations by rt –pcr analysis of the lymphoid differentiation markers rag-1 and pre t-alpha. in all samples , transcripts of both markers could be detected from day 0 though day 11, however , in case of pre – t-alpha, nested pcr was always required , indicating lower expression . these findings; therefore, demonstrate that t-cell differentiation events (as opposed to mere expansion) do occur in stroma cell free expansion assays.