XI International Meeting on Paracoccidioidomycosis

XI International Meeting on Paracoccidioidomycosis

Resume:13-1

Poster (Painel)

13-1

Saccharomyces cerevisiae as a Vaccine Vehicle Against Paracoccidioidomycosis

Authors:

Mariana Aprigio Assis (FMRP-USP - Faculdade de Medicina de Ribeirão Preto) ; Luciana Pereira Ruas (FMRP-USP - Faculdade de Medicina de Ribeirão Preto) ; Aline Ferreira Oliveira (FMRP-USP - Faculdade de Medicina de Ribeirão Preto) ; Carol Kobori Fonseca (FMRP-USP - Faculdade de Medicina de Ribeirão Preto) ; Maria Cristina Roque-barreira (FMRP-USP - Faculdade de Medicina de Ribeirão Preto) ; Paulo Sergio Rodrigues Coelho (FMRP-USP - Faculdade de Medicina de Ribeirão Preto)

Abstract

The non-pathogenic yeast Sacharomyces cerevisiae offers many advantages as a vaccine vehicle: This yeast species is easily manipulated genetically and contains an intrinsic adjuvant property (beta-glucan cel wall). Recombinant S. cerevisiae expressing foreign antigens can activate dendritic cells and elicit robust antigen-specific T lymphocyte responses. In order to test S. cerevisiae as a vaccine vehicle against Paracoccidioidomycosis (PCM). We engineered S. cerevisiae yeast to express the glycoprotein gp43, a dominant antigen that confers partial protection against PCM. Gp43 was cloned in a plasmid under the control of GAL1 promoter so overexpression was achieved with the addition of galactose to the culture medium. Anti-gp43 antibody recognized the induced recombinant protein in immunoblot assays of total S. cerevisiae yeast protein extracts. The recombinant yeast was heat killed and intraperitoneously inoculated 3 times in BALB/c mice. Three weeks after the last dose, the mice were intravenously infected with P. brasiliensis yeast. A group of mice inoculated with S. cerevisiae yeast bearing an empty plasmid and a group inoculated with PBS were used as controls. After 30 days mice were sacrificed and the organs collected (lung and spleen). The fungal burden was evaluated by counting the colony forming units (CFU) per gram of organ tissue. Lungs and spleens of mice vaccinated with recombinant yeast showed reduced fungal burden compared with the control groups. Analysis and quantification of cytokines were performed. Mice vaccinated with recombinant yeast showed a significant increase of IL-12 and IFN-γ compared to the control groups. We confirmed the protective role of the yeast expressing gp43 by histological analysis of lungs. The group with recombinant yeast presented a reduction in the number of granulomas and maintenance of alveolar septa compared to the control groups. Taken together, the results indicate that the yeast vaccine elicited a Th1-type immune protection against PCM.

Keyword: Paracoccidioides brasiliensis, Saccharomyces cerevisiae, Vaccine

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