1984 Volume 32 Issue Supplement9 Pages 120-126
Effects of AC-1370, a novel semisynthetic cephalosporin, on host defense against infections and its target cells were investigated. AC-1370 exerted no effect on plaque forming cells and delayed type hypersensitivity but augmented phagocytosis by macrophages and neutrophils by in vitro application and also in vivo. In contrast, other β-lactam antibiotics either did not affect or rather suppressed these functions. Flow cytometry revealed that most of the cells binding AC-1370 were macrophages and that few neutrophils bound AC-1370. Culture supernatants of macrophages potentiated phagocytosis by neutrophils, and the culture supernatants of AC-1370-stimulated macrophages potentiated phagocytosis by neutrophils more potently than the culture supernatant of unstimulated macrophages did. The activities of these culture supernatants were resistant to heat treatment at 56° for 30 minutes but labile to the treatment with trypsin. These results suggest that AC-1370 potentiates phagocyte functions without affecting humoral and cellular immune responses and that the potentiating action of AC-1370 may be mediated by direct binding of the compound to macrophages and by indirect action on neutrophils through facilitating production of protein factor (s) by macrophages.
