Abstract:
Limited antifungal drugs, their high toxicity, and the emergence of resistant Candida albicans strains indicate the need for novel therapeutic strategies. The objectives of this study were to prepare antibodies against C albicans in an egg-laying hen and evaluate the efficacy of these antibodies in preventing the dissemination of C albicans in BALB-c mice. An egg-laying hen was immunized with a mixture of heat-killed C albicans yeast cells and germ tubes. Egg yolk immunoglobulin (IgY) was extracted and purified from the yolk of eggs laid before and after immunization. Anti-C albicans IgY antibodies in the extracts were detected by enzyme-linked immunosorbent assay. The protective efficacy of post-immunization IgY was tested by injecting groups of BALB-c mice with a lethal dose of C albicans and a variable regimen of pre- or post-immunization IgY. The results indicated the following: 1) all the mice that received either pre- or post-immunization IgY survived at 7 days post-challenge compared with 20percent of those in the untreated controls; 2) mean candidal colony forming units (CFU-mg) of kidney tissue were 25 × 108 ± 5.4 × 108 in untreated mice and 10 × 103 ± 1.4 × 103 in mice treated with pre-immunization IgY; no C albicans colonies could be detected in all challenged mice that were treated with post-immunization IgY; 3) multiple abscesses were observed in kidneys obtained from mice treated with pre-immunization IgY. No abscesses were seen in kidneys obtained from mice injected with post-immunization IgY. Post-immunization IgY might be considered a prophylactic agent or possibly an adjunct to antifungal therapy. Pre-immunization IgY appeared to contain factors that prolonged survival, but did not prevent dissemination of the fungus.