A comparative analysis of macrophage activation in C57B1/6 mice treated with inflammatory compounds or bearing Lewis lung carcinoma.

The different percentages of acid hydrolases released by peritoneal macrophages obtained from C57B1/6 mice injected i.m. with talc, carrageenan or 3LL cells, and also the demonstration that hydrolase secretion from in vitro macrophage monolayers of tumor-bearing mice undergoes a further increase when zymosan is added to the culture, strongly suggest the possibility that more than one membrane surface receptor is involved in the triggering of lysosomal enzyme release. Furthermore, there is evidence from the reported results that, besides immune complexes, neoplastic cells or their metabolic product(s) could act as inducers of the lysosomal enzyme secretion by macrophages.