Amplification of T Cells from Human Cord Blood in Serum-deprived Culture Stimulated with Stem Cell Factor, Interleukin-7 and Interleukin-2

We report the effects exerted by cytokine combinations, including stem cell factor (SCF), interleukin-7, interleukin-4 and interleukin-2, on the amplification of T cells from cord blood (CB) mononuclear cells cultured for 10-11 days under serum-deprived conditions. Of all the combinations investigated, SCF+interleukin-7 sustained the best fold increase (FI) of total nucleated cells (FI=6.4+/-1.17), amplifying preferentially CD4(+) over CD8(+) T-cell subsets (FI=4.72+/-0.79 vs 2.73+/-1.2, respectively, P<0.05). The addition of interleukin-2 to this combination did not significantly increase the total number of cells generated (FI=7.4+/-2.27), but allowed preferential amplification of CD8(+) over CD4(+) T cells (FI=6.04+/-0.14 vs 1.67+/-0.6, respectively, P<0.05). Single-strand conformation polymorphism analysis of the T-cell receptor V(beta)-chain rearrangements expressed by the expanded T cells indicated that the complexity of the T-cell repertoire had increased after 10 days of culture in the presence of SCF and IL-7. Interestingly, a modest expansion (FI=8.67+/-1.5) of myeloid progenitor cells was also observed in these cultures. These results indicate that it is possible to expand specific T-cell subsets for adoptive immunotherapy without losing myeloid progenitor cells necessary for neutrophil recovery after CB transplantation, by modulating the cytokines added to the cultures.