Effects of rIL-7 on murine bone marrow NK precursor cells.
We recently demonstrated that functional NK cells are produced from their precursors in murine long-term bone marrow cultures without the addition of exogenous growth factors. Because IL-7 is known to be produced by bone marrow stromal cells and is a proliferation factor for some immature cells of the B and T cell lineages, we tested whether rIL-7 could support the proliferation or maturation of NK precursor cells. By itself, rIL-7 did not induce NK lytic activity in cultures of unseparated bone marrow cells (BMC), but it did augment the response of unseparated BMC to 50 U rIL-2/ml, with a maximal enhancement at 10 ng IL-7/ml. Depletion experiments demonstrated that the IL-7-induced increase in cytotoxicity was not due to NK precursors, however, but to mature T and NK cells. IL-7 preferentially increased the number of CD8+ cells. Preculture of NK 1.1-depleted BMC with IL-7 did not increase the total number of NK 1.1+ cells or the lytic activity generated from NK precursor cells. However, IL-2-responsive NK lineage cells survived better in IL-7-supplemented medium than in medium alone. Thus, soluble rIL-7 did not expand the NK precursor cell population in vitro but it maintained the viability and subsequent responsiveness to IL-2 of NK precursors.
Pollack
S B
SB
Department of Biological Structure, School of Medicine, University of Washington, Seattle 98195.
Tsuji
J
J
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D046508:Culture Techniques; D005260:Female; D006412:Hematopoietic Stem Cells / Q000187:drug effects*; D016130:Immunophenotyping; D007376:Interleukin-2 / Q000494:pharmacology; D015851:Interleukin-7 / Q000494:pharmacology* / Q000502:physiology; D007694:Killer Cells, Natural / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects
D007376:Interleukin-2; D015851:Interleukin-7; D011994:Recombinant Proteins