Effect of beta-Estradiol and Testosterone on Candida albicans growth rate and Candida albicans-induced immune function

Gender plays a major role in an organism’s immune response to many pathogens. However, little is known about gender’s effect on Candida albicans (C. albicans) infections. C. albicans is a commensal organism that lives in the mucosa and skin of healthy individuals, however, C. ablicans can become an opportunistic pathogen in immunocompromised individuals. In our laboratory, it has been found that female mice are significantly more resistant to systemic C. albicans infections than male mice. Furthermore, castrated males are as resistant to the infection as female mice and that 5α-dihydroxytestosterone (the stable form of testosterone) supplementation of female mice decreases their ability to resist the yeast infection. Tumor necrosis factor-alpha (TNF-α), primarily secreted by macrophages, was one of the cytokines most affected by the sex hormone treatment. Thus, we suspect sex hormones play an important role in the immune response to C. albicans infection. It is possible that sex hormones (1) alter the growth rate of C. albicans and/or (2) that sex hormones alter immune responses to the yeast. To address (1), C. albicans was treated with different concentrations of β-estradiol (E2) or Testosterone (T), the yeast were plated on SAB agar, incubated at 37C and 24h later the yeast colonies were counted. To address (2), immortalized female (J774A.1) or male (RAW264.7) murine macrophages and Thiogylcollate-induced macrophages (TG-i M) derived from female and male c57BL/6 mice were treated with 1nM E2 or 10nM T for 24h and then challenged with C. albicans for various time points. Cytokines ((TNF-), interleukin-1 (IL-1), IL-6 and IL-10) and inducible nitric oxide synthase mRNA expression was determined via RT-qPCR. The concentration of TNF-, IL-2 and IL-6 protein secretion was quantified via Enzyme-linked Immunosorbent Assay. E2 inhibited TNF- protein secretion from J774A.1 after a 2h and 4h C. albicans challenge, however, E2 stimulated TNF- protein secretion from female derived TG-i M challenged for 24h with the yeast. Interestingly, while E2 had no effect on TNF- mRNA levels in yeast-challenged J774A.1 cells, this sex hormone suppressed TNF- mRNA levels in TG-i M cells. This results suggest that E2’s effects on TNF- mRNA produced from female derived macrophages is post-transcriptional and cell type dependent. E2 reduced IL-1 mRNA levels only in female derived TG-i M cells, but not in J77A.1 cells, supporting our hypothesis that E2’s effects are cell type dependent. E2 suppressed C. albicans-induced TNF- protein secretion from male derived TG-i M, but not from the immortalized male cell line RAW264.7. E2 had no effect on cytokine mRNA levels in male derived TG-i M, but E2 decreased TNF- mRNA levels while increasing IL-10 mRNA levels in RAW264.7 cells challenged with C. albicans for 2h. T did not affect the protein secretion of C. albicans-induced TNF- from female derived macrophages. However, T suppressed TNF- and IL-10 mRNA expression from J774A.1. T had no effect on cytokine mRNA levels in female derived TG-i M cells. T suppressed TNF- protein secretion from RAW264.7 cells, but stimulated the TNF- secretion from male derived TG-i M. These results suggest that E2, and to a lesser extent T, can alter C. albicans-induced cytokine production from macrophages derived from both sexes, and that these sex hormones act in a post-transcriptional manner.