ALTERATION IN IL-1 AND ARGINASE ACTIVITY OF TUMOR-ASSOCIATED MACROPHAGES - A ROLE IN THE PROMOTION OF TUMOR-GROWTH

The present investigations were undertaken to study whether the macrop hages associated with Dalton's lymphoma (DLAM), a spontaneous T-cell l ymphoma, are modulated for the secretion of tumor growth-promoting fac tors in ascites. The DL ascitic fluid (DLAF) and the culture supernata nts of DLAM harvested from mid and late tumor-bearing stages, but not early tumor-bearing stage, enhanced the proliferation of DL cells in v itro. These observations indicate that DLAF contains certain DL growth -promoting substances and at least some of them are secreted by DLAM. The DLAM obtained from mid and late tumor-bearing stages showed enhanc ed IL-1 production and arginase activity, with a concomitant decline i n the RNI production, which could be implicated in the DLAM-mediated p romotion of tumor growth.