title: Physiology of natural killer cells. In vivo regulation of progenitors by interleukin 3.
abstract: Adoptive transfer of bone marrow cells to syngeneic lethally irradiated C57BL/6 mice was used to study the maturation of natural killer (NK) cells from their progenitors. The NK progenitor cell was found to be asialomonoganglioside-negative, (aGM1-) Thy-1-, NK-1-, Ly-1-, Ly-2-, and L3T4-. The NK cells emerging from the bone marrow grafts were aGM1+, NK-1+, Thy-1+/-, Ly-1-, Ly-2-, and L3T4- and to have a target specter similar to that of NK cells isolated from the spleen of normal mice. The regulatory role of interleukin 2 (IL-2) and interleukin 3 (IL-3) for the maturation of NK cells was examined by exposure of the bone marrow cells to the lymphokines in vitro before bone marrow grafting or by treatment of bone marrow-grafted mice with lymphokines through s.c. implanted miniosmotic pumps. IL-3 antagonized the IL-2-induced maturation of NK cells in vitro and strongly inhibited the generation of NK cells after adoptive transfer of bone marrow cells in vivo. The suppressive effect of IL-3 was evident throughout the treatment period (8 or 16 days) but was apparently reversible because NK activity returned to control levels within 8 days after cessation of treatment. The inhibition of cytotoxic activity was accompanied by a reduced appearance of cells with the NK phenotypic markers aGM1 or NK-1, indicating that not only the cytotoxic activity of NK cells but also their actual formation was inhibited. Concomitantly, a moderate increase in cells expressing the T cell marker L3T4 and an increased proliferative response to the T cell mitogen concanavalin A was observed. A direct estimate of the effect of IL-3 on the frequency of NK cell progenitors was obtained by limiting dilution analysis of bone marrow cells at day 8 after bone marrow transplantation. The estimated minimal frequency of NK cell progenitors was reduced from 1/11,800 in control to 1/41,900 in IL-3-exposed mice. IL-3 may take part in the homeostasis of NK cells by the down-regulation of their progenitors.
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D007116:Immunization, Passive; D007376:Interleukin-2 / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL / Q000276:immunology; D011828:Radiation Chimera
chemical_list: D007376:Interleukin-2; D007377:Interleukin-3