The effect of interleukin-12 in ex-vivo expansion of human haemopoietic progenitors.
ABSTRACT We evaluated progenitor cell proliferation in cultures supplemented by different cytokine combinations in the presence or absence of IL-12. In cultures of low density cells, cytokine combinations including IL-12 were associated to a greater proliferation (up to 6.7 +/- 2.5 CFU-GM fold expansion). However, in cultures of purified CD34+ cells the more efficient cytokine combination (147 +/- 49 CFU-GM fold expansion) was SCF, IL-3, IL-11 and MIP-1 alpha, and the addition of IL-12 did not further enhance expansion of progenitors. These results indicate that accessory cells, lost in CD34+ cell purification, could be in part responsible for IL-12 effect on progenitor cell proliferation. In CD34+ cell cultures the addition of IL-12 led to CD19 mRNA generation, suggesting that IL-12 acts on haemopoietic cells with both myeloid and lymphoid potential.