Anticytokine activity of Candida spp. and their ability to produce cytokine-like substances

Abstract

Bacteria are known both to exhibit anticytokine activity (ACA), i.e., to secrete extracellular compounds which inactivate / neutralize various cytokines, and to produce cytokine-like substances (CPV) released to the culture medium. At the same time, the ability of Candida to secrete such substances has not been previously studied. The purpose of our study was to determine the presence of ACA and the ability to produce CPV in Candida strains isolated from the reproductive tract of apparently healthy pregnant women. The experimental series included 26 clinical strains of Candida spp. isolated from vaginal secretions. Isolation and identification of fungal species was based on morphological and biochemical criteria. ACA against IL-4, IL-6, IL-8, IL-10, IL-17A and TNF were detected following 2-hour co-incubation of fungal suspensions with solutions of the distinct cytokines at a ratio of 1:1. Determination of the cytokine concentrations was carried out by ELISA using the Cytokin kits (St. Petersburg). ACA amounts were defined as the percentage of cytokine inactivation in experimental samples compared to the control expressed as pg/mL. Their ability to produce CPV was expressed as percentage of cytokine production in experimental specimens compared to the controls (pg/mL). The obtained data were subjected to statistical evaluation. ACA of Candida spp. and their ability to produce CPV were revealed for the first time. with appropriate differences established between the studied Candida species, i.e., cultures of C. non-albicans showed ACA more often for the pro-inflammatory cytokines; C. albicans isolates showed more frequent production of the substances, similar to the pro-inflammatory cytokines IL-8, IL-17A, and TNF. Expression of ACA against IL-10 and ability to produce the anti-inflammatory IL-4- and IL-10-like substances were significantly higher in the cultures of C. non-albicans species. The results of these experiments expand our knowledge on the spectrum of Candida biological activities and require further study.