LYSOZYME STIMULATES LYMPHOCYTE-RESPONSE TO CONA AND IL-2 AND POTENTIATES 5-FLUOROURACIL ACTION ON ADVANCED CARCINOMAS

The oral administration of 100 mg/Kg/day of hen egg-white lysozyme (Ly sozyme) for 8 consecutive days to mice bearing advanced MCa mammary ca rcinomas and treated with 5-fluorouracil (5-FU) increases the efficacy of 5-FU on primary tumor growth and on lung metastasis formation and particularly on the postsurgical survival time. These effects are acco mpanied by the correction of the reduced in vitro response to ConA of lymphocytes obtained from the spleen of the treated mice. In vitro, ly sozyme is capable of inducing proliferative activity in a population o f blast cells, obtained by a mixed population of mononuclear cells har vested from the spleen of healthy mice, and of evoking a marked prolif erative effect to IL-2 ina condition in which, in lysozyme untreated l ymphocytes, IL-2 is completely uneffective. These data stress the effe cts of lysozyme on host immunity following oral administration and mor eover indicate the beneficial role of this peptide in conditions in wh ich the increase of host responses can significantly contribute to the success of the theatment.