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Abstract

Candida albicans is one of the main fungal pathological agents. In this context, the variety of available antifungals is limited, and toxicity limits their use. Therefore, the production of antibodies against microbial structures, to be used in immunotherapies, are options with reduced adverse effects. Among the possible therapeutic targets against C. albicans, the high-affinity iron permease Ftr1 seems to be promising, as its blockade prevents iron uptake by yeast and influences its virulence. In this context, this work aimed to evaluate in vitro antifungal activity of IgY antibodies against Ftr1 of C. albicans, which were produced and extracted from yolks of laying hens immunized with the protein. The in vitro antimicrobial activity was established by microdilution in a medium lacking iron to promote the expression of the Ftr1 gene. The concentration of antibodies ranged from 3.9 μg/mL to 1 mg/mL. Additionally, the minimum fungicidal concentration (MFC) was determined. As a result, it was observed that in the presence of the iron chelator (BPS), the concentration that inhibited 90% of the growth (MIC90) of the anti-Ftr1 IgY was 250 μg/mL for the wild strain, C. albicans SC5314, and for the non-iron permease producing mutant, Δftr1. In the absence of BPS, the MIC90 was equivalent to 500 μg/mL. The pre-immune IgY (control) also showed antifungal action, but the MICs found were almost always higher (500 μg/mL). Regarding MFC, for IgY anti-Ftr1 it was equivalent to 500 μg/mL for C. albicans SC5314 in all conditions tested. This result was also obtained for the Δftr1 mutant strain incubated in the absence of BPS. In contact with BPS, the MFC was 250 μg/mL. Different results were found for treatments with pre-immune IgY. MFC was equivalent to 1 mg/mL, except when C. albicans SC5314 was incubated with 25.0 mM BPS (CFM = 500 μg/mL). In summary, IgY inhibited the growth of wild-type and non-Ftr1 producing mutant C. albicans strains. It also showed fungicidal action against these strains. An explanation for this would be because IgY probably inhibited iron uptake also from Ftr2, another iron permease that has 87% identity with Ftr1, and is expressed in the presence of iron. Pre-immune IgY showed antifungal activity probably because C. albicans is present in the intestinal microbiota of chickens and induces the production of antibodies against this fungus. Therefore, in general, anti-Ftr1 IgY has been shown to have activity against C. albicans.

Institutions
  • 1 Departamento de Microbiologia/Universidade Estadual de Londrina
  • 2 Departamento de Patologia, Análises Clínicas e Toxicológicas/Universidade Estadual de Londrina
  • 3 Departamento de Ciências Patológicas/Universidade Estadual de Londrina
Track
  • Microbiologia Médica Humana
Keywords
Immunoglobulin Y
reductive pathway
candidiasis
mycoses
egg