The effect of a calf thymus acid lysate on bone marrow cell growth in vitro.

AbstractGranulocyte-macrophage colony forming units (CFU-GM) were studied in cultures of bone marrow from 16 apparently healthy normal controls, 9 patients with the myelodysplastic syndrome, 5 patients with myeloproliferative disease and 2 with myeloma. Supernatants from non-stimulated 72 hr cultures of nonadherent mononuclear blood cells (“lymphocytes”) stimulated the forming of an average of 38.4 colonies per 100000 cells from normal marrow. The addition of GIBCO's commercial conditioned medium or of a medium produced by lymphocytes stimulated with different concentrations (5,10 and 20 mcg/ml) of an acid lysate of thymus (thymomoduline), increased growth to 65.2–55.4 colonies (p <0.001 to 0.05). Similarly, a significant increase (p < 0.05) was found in the number of clusters and colonies formed in cultures of marrow from patients with the myelodys-plastic syndrome. In contrast, no growth was found when the thymus acid lysate was added directly to the bone marrow cultures, suggesting that the lysate indu...