COMPARATIVE EFFECTS OF PARTICULATE AND SOLUBLE GLUCAN ON MACROPHAGES OF C3H/HEN AND C3H/HEJ MICE

In order to compare both the actions of soluble glucan (glucan-F) and particulate glucan (glucan-P) on macrophages and the responsiveness of macrophages from C3H/HeJ and C3H/HeN mice to these immunomodulators, interleukin-1 (IL-1) levels, phagocytosis and superoxide production were monitored after an in vitro exposure to glucan-F or glucan-P. A 2 or 20 h exposure to either glucan preparation decreased the ability of both C3H/HeJ and C3H/HeN macrophages to ingest zymosan. In contrast, glucan-P, but not glucan-F, decreased (after a 20 h exposure) the uptake of both IgG opsonized erythrocytes and latex beads. Furthermore, glucan-P, but not glucan-F was as effective as zymosan (after a 1 h exposure) in inducing superoxide release by macrophages isolated from both C3H/HeN and C3H/HeJ mice. While the effects of glucan-P on PMA-induced superoxide release and IL-1 levels were similar in macrophages from C3H/HeJ and C3H/HeN mice, glucan-F was ineffective at enhancing PMA-induced superoxide release or increasing IL-1 levels in C3H/HeJ mice. Thus (1) the effects of glucan-P on phagocytosis of opsonized erythrocytes and latex beads are not mimicked by glucan-F and (2) while macrophages from C3H/HeJ mice respond normally (as compared with C3H/HeN macrophages) to glucan-P, they are hyporesponders to glucan-F. These findings indicate that the activation of macrophages by glucan-P involves different (or additional) pathways from those activated by glucan-F.