Characterizing the ability of novel, cytokine-producing Candida albicans strains to alter the course of a disseminated infection

Candida albicans is a ubiquitous fungus that is found on the skin and mucosal surfaces of the human body; however, when the immune system is compromised, C. albicans can act as an opportunistic pathogen, causing a wide range of infections. Recent studies have suggested that IL-17A, produced as a result of Th17 cell differentiation, and TNF-alpha play critical roles in both the inflammatory and protective responses to C. albicans infections. In order to clarify the roles of TNF-alpha and IL-17A in candidiasis, this project was designed to construct genetically engineered strains of C. albicans that secrete either murine TNF-alpha or IL-17A cytokines. Codon modified TNF-alpha/IL-17A sequences were cloned in-frame with the C. albicans MFalpha1 secretion signal sequence and placed under the control of the tetracycline regulatable tetO promoter in a C. albicans integrating plasmid vector. Several tests and immunological assays were performed to confirm correct integration and determine if detectable levels of cytokines were produced. A mouse study was performed which corroborated recent findings with regards to the increased survival rates due to the increased production of IL-17A in disseminated C. albicans infections. Additional in vitro assays were performed which indicate the possibility that IL-17A binds directly to C. albicans hyphae, negatively affecting its viability.