Linear Epitopes of Paracoccidioides brasiliensis and Other Fungal Agents of Human Systemic Mycoses As Vaccine Candidates

Abstract

Dimorphic fungi are agents of systemic mycoses associated with significant morbidity and frequent lethality in the Americas. Among the pathogenic species are Paracoccidioides brasiliensis and Paracoccidioides lutzii, which predominate in South America; Histoplasma capsulatum, Coccidioides posadasii, and Coccidioides immitis, and the Sporothrix spp. complex are other important pathogens. Associated with dimorphic fungi other important infections are caused by yeast such as Candida spp. and Cryptococcus spp. or mold such as Aspergillus spp., which are also fungal agents of deadly infections. Nowadays, the actual tendency of therapy is the development of a pan-fungal vaccine. This is, however, not easy because of the complexity of eukaryotic cells and the particularities of different species and isolates. Albeit there are several experimental vaccines being studied, we will focus mainly on peptide vaccines or epitopes of T-cell receptors inducing protective fungal responses. These peptides can be carried by antibody inducing β-(1,3)-glucan oligo or polysaccharides, or be mixed with them for administration. The present review discusses the efficacy of linear peptide epitopes in the context of antifungal immunization and vaccine proposition.

Keywords: Paracoccidioides; antibody; fungi; peptide; vaccine.

Figure 1

Lung tissue from BALB/c mice infected with Paracoccidioides brasiliensis vaccinated or not with peptide P10. (A) Lung tissue of control only infected mice. Bar, 400 μm. (B) Lung tissue of mice infected with Paracoccidioides brasiliensis and vaccinated with P10 in presence of cationic lipid. Bar, 400 μm. (C) Highly magnified lung tissue of control, only infected mice. Bar, 50 μm. (D) Lung tissue of mice infected with Paracoccidioides brasiliensis and vaccinated with P10 in presence of cationic lipid. Bar, 400 μm. Slides were stained with Grocott-Gomori methenamine silver. Pictures were taken using EVOS fluorescence microscopy (AMG). The Animal Care and Use Committee of the University of São Paulo approved all in vivo testing.