ROLE OF MACROPHAGES IN THE CANDIDACIDAL ACTIVITY OF LIPOSOMAL AMPHOTERICIN-B

The role of macrophage activation in the candidacidal activity of lipo some-incorporated (L) amphotericin B was investigated. Macrophages tre ated with L-amphotericin B killed Candida albicans more effectively th an did macrophages treated with free (F) amphotericin B. However, macr ophages treated with neither F- nor L-amphotericin B killed amphoteric in B-resistant Candida tropicalis. In vivo stimulation of macrophages by intraperitoneal administration of thioglycollate, Freund's complete adjuvant, or heat-killed C. albicans followed by in vitro treatment w ith F- or L-amphotericin B, did nor enhance their candidacidal activit y. intravenous administration of F- or L-amphotericin B did not augmen t the candidacidal activity of macrophages sensitized in vivo; however , sensitized macrophages showed enhanced killing compared with residen t unstimulated cells. These studies suggest that macrophage-mediated e nhancement of C. albicans killing mag he due to uptake, transport, and delivery of L-amphotericin B to infected sites rather than to macroph age activation.