| Abstract: | Summary. Bone marrow (BM) stromal cells express CD10 (cALLA), a surface antigen now known to be a neutral endopeptidase (NEP-24.11). The function of CD10 in BM stroma is unknown, although purified NEP-24.11 is known to degrade different substrates including interleukin 1β (IL-1β). We have therefore employed a CD10-positive BM stromal cell line (L2AK) which proliferates in response to IL-1β to test the hypothesis that degradation of this cytokine is one of the functions of stromal CD10. We first showed that [3H]thymidine incorporation by L2AK cells is enhanced by IL-1β in a clear dose-dependent manner. Addition of the CD10 inhibitor, phosphoramidon, together with IL-1β resulted in a left shift in the dose-response curve which corresponded to a 10-fold potentiation of the IL-1β effect. These results indicate that CD10 on bone marrow stromal cells can degrade IL-1β and therefore provide a local control of the effects of this, and possibly other, growth factor(s). |
