CONSTITUTIVE PRODUCTION OF IL-6 IN THE ANEMIC MICE OF W W-V GENOTYPE/

IL-6 was found to be produced by bone marrow cell fraction enriched fo r hemopoietic stem cells in response to IL-3 stimulation. To confirm t he production of IL-6 by hemopoietic stem cells, we studied the respon se of W/W-v mouse bone marrow cells to IL-3 stimulation in terms of IL -6 production. Genetically anemic mice of W/W-v genotype are known to be depleted of normal hemopoietic stem cells. Bone marrow cells of W/W -v mice produce IL-6 without IL-3 stimulation. But bone marrow cells o f the litter mate (+/+) mice studied as controls do not produce IL-6 w ithout stimulation. IL-3 induced the production of IL-6, GM-CSF and G- CSF from the bone marrow cells of +/+ mice. Gene expression of IL-6, G M-CSF, G-CSF and IL-3 in these mice was detected in total bone marrow cells after IL-3 stimulation. In contrast, bone marrow cells of C3H mi ce did not produce IL-3 even after IL-3 stimulation. Bone marrow cells of C3H mice reportedly produce a diffusible IL-3 inhibitor (NIL-3), b ut those of C57BL mice do not. Present findings indicate the strain-de pendent differences in hemopoietic stimulating factor production. The constitutive IL-6 production in W/W-v mice might be due to a constant and strong demand for blood cell production of the anemic mice.