Growth-stimulating phase of macrophage response to activation: the phenomenon and its implications for tumour growth and immunotherapy.

The dynamics of growth-stimulating and cytotoxic activity of mouse peritoneal macrophages (PMo) in response to in vivo and in vitro bacillus Calmette-Guérin (BCG) or bestatin treatment was studied. It was shown that BCG and bestatin induce cytotoxicity in PMo, and that after the cytotoxic response strong growth-stimulating activity develops. PMo, rendered cytotoxic in vivo and afterwards cultivated in vitro, displayed the same switch from a cytotoxic to a growth-stimulating phase.