Candida albicans mannan extract-protein conjugates induce a protective immune response against experimental candidiasis

Candida albicans mannan extracts encapsulated in liposomes were previously used to stimulate mice to produce antibodies protective against candidiasis . In the present study, mannan-protein conjugates without liposomes were te sted as vaccine candidates. Mannan extracts were coupled to bovine serum al bumin, and isolated conjugates consisted of carbohydrate and protein at a r atio of 0.7-1.0. Vaccination of mice with the conjugate and an adjuvant yie lded antiserum that contained Candida agglutinins, Vaccinated mice challeng ed with yeast cells had a mean survival time of 56 days, compared with <13 days for control groups. The antiserum protected naive animals against diss eminated disease. Naive mice given the antiserum intravaginally developed 7 9% fewer fungal colony-forming units, compared with control groups. The ser um-protective factor was stable at 56 degrees C and was removed by adsorpti on with yeast cells. It is concluded that the conjugate vaccine can induce protective antibody responses against experimental disseminated candidiasis and Candida vaginal infection.