Induction of candidicidal activity in mice by immunization withCandida albicansribosomes

Testing Antifungal Vaccines in an Animal Model of Invasive Candidiasis and in Human Mucosal Candidiasis

The following article will concentrate on the NDV-3 anti-Candida and Staphylococcus vaccine. The vaccine is composed of the N-terminal portion of the Candida albicans agglutinin-like sequence 3 protein (Als3p) and aluminum hydroxide as adjuvant. The vaccine conferred protection to mice against experimental vaginal, oral, and intravenous challenge with C. albicans. Due to the sequence and structural homology of the Als3p with Staphylococcus aureus surface proteins, the vaccine also protected against experimental skin and IV infection with S. aureus. The vaccine has reached the stage of human trials: phase 1 clinical studies have shown that the vaccine is safe and immunogenic. The latest brief conference abstract reports of vaccination in women suffering from recurrent vaginal candidiasis, indicating that the recurrence rates were lower in the women receiving the vaccine.

Immunization protocols for use in animal models of candidiasis

Immunoprotection during most forms of candidiasis (oropharyngeal, invasive) is lacking since most candidiasis patients are immunosuppressed either as a result of their allogeneic transplant, cancer chemotherapy, or HIV infection. Consequently, immunization might be considered as an unlikely way to protect patients from such infection. Nonetheless, there are a number of investigations that indicate active immunization or the passive treatment with hyperimmune, specific antibodies can result in protection in models of experimental candidiasis. The former subject, active immunization, is the subject of this chapter. We focus on recent efforts with the Als family of cell wall proteins to serve as a model, and also offer immunization methods in candidiasis models that can be adapted to any antigen of the organism.

Vaccines against fungal infections

The state-of-the-art reached in developing protective immunity against fungal infections through vaccination makes a survey of methodologies and results timely. This review describes experimental vaccinations against dermatophytes, pathogenic yeasts, and dimorphic fungi with special attention to the anti-Coccidioides immitis vaccine, which has reached clinical trials, and to the anti-Candida albicans and anti-Histoplasma capsulatum ribosomal vaccines. Also covered are vaccination experiments in compromised hosts aimed at eliciting acquired resistance to opportunistic fungal infections which constitute risk factors for these hosts. Immunization procedures include live, killed, and attenuated organisms, as well as different subcellular fractions such as cytoplasmic extracts, fungal culture filtrates, cell walls, or ribosomal fractions. A variety of experimental animal models and isolated human trials constitute the subjects in these studies. Acquired immunity has been evaluated through assessment of resistance to infection and determination of specific immune responses. It has been demonstrated that fungal vaccines do elicit both humoral and cell-mediated immunity in the immunized host. For some vaccines (e.g., H. capsulatum), a correlation between the induced immunity and protection was observed and the immunity could be adoptively transferred. In view of the potential of vaccines against fungal infections, a perspective on their applicability, significance, and value for human use is discussed.