Thymomodulin stimulates phagocytosis in vitro by rat macrophages and human polymorphonuclear cells.

Activation of non-specific host defenses can increase resistance to infection in patients and especially those with reduced immune response. Thymomodulin is a calf thymic derivative containing low molecular weight peptides, which exerts immunomodulating activity probably through an enhancement of lymphocyte functions. To explore this possibility, rat macrophages (MP) and human polymorphonuclear (HPMN) cells were incubated in vitro with 100, 200, 400 micrograms/ml of thymomodulin at 37 degrees C for 60 min and their phagocytic activity was investigated. The number of phagocytosing cells was significantly increased following increasing concentrations of thymomodulin and the percentage of phagocytosis was increased more for human PMNs in comparison with rat MP, while the values of the phagocytic index were not modified after challenge with thymomodulin both for MPs and HPMNs.