Lysozyme-enhanced killing of candida albicans and coccidioides immitis by amphotericin b

The concentration of amphotericin B required to inhibit the growth in chemically defined media of 3 strains of Candida albicans and the spherule and mycelial growth phases of Coccidioides immitis Silveira strain was decreased 4-to-16-fold by the incorporation of 5-10 μg lysozyme /ml. Despite this enhancement of sensitivity to amphotericin B by physiological (serum) concentrations of lysozyme, the 3 C. albicans strains and the mycelial phase of C. immitis in the absence of amphotericin B were not inhibited by 1000-2000 μg lysozyme/ml. In contrast, the spherule phase of C. immitis was inhibited by 5-20 μg lysozyme/ml. Ten μg lysozyme/ml markedly but reversibly altered the characteristic absorption spectra of amphotericin B and amphotericin B- cholesterol complexes thus suggesting that the lysozyme enhanced sensitivity to amphotericin B shown in lysozyme-insensitive strains may be a consequence of lysozyme binding to cell membrane sterol-amphotericin B complexes.