5B). These results were in line with immunohistochemical data showing Gefitinib order that a higher percentage of CD4+ lymphocytes than neutrophils were positive for IL-17 (Fig. 4). Importantly, the IL-17 we detected on cells

could have originated from endogenous or exogenous factors and bound by IL-17 receptors on cell surfaces [21, 22]. To determine if these leukocytes were actively expressing IL-17, the cells were subjected to fixation and permeabilization. The fluorescence intensity of IL-17 staining increased slightly, but with statistical significance, in both CD4+ T cells and Ly-6G+ cells (Fig. 5B and Supporting Information Fig. 5). These resulted indicated that infiltrated lymphocytes and neutrophils express IL-17. Since fungal growth and leukocyte infiltration coordinately contribute to corneal destruction, YAP-TEAD Inhibitor 1 nmr we wondered whether either of these processes was occurring in inoculated nude mice. In inoculate BALB/c mice, pseudohyphae were detected as early

as 6 h postinoculation and abundant by 12 and 24 h postinoculation (Fig. 6A). In striking contrast, few pseudohyphae were detected at these time points in nude mice. Similarly, leukocyte infiltration was already obvious in the corneas of BALB/c mice at 6 h, but few leukocytes were present in nude mice throughout the observation period (Fig. 6A and B). Colony-forming assay showed that the pathogen burdens gradually increased in immunocompetent mice, but decreased in nude mice soon after inoculation (Fig. 6C). Together, these results suggest that nude mice have an innate mechanism that inhibits Candida blastospore transformation

and leukocyte infiltration. In next support of the latter, real-time polymerase chain reaction (RT-PCR) assay demonstrated that the expression of chemokines (e.g. CXCL12, CXCL10, CXCL2, CXCL1, and CCL2) including the IL-17 inducer IL-6 was upregulated during the first day of inoculation in BALB/c and nude mice, but their levels were significantly lower in nude mice (Fig. 6D). To determine whether the decreased production of chemokines in nude mice corneas was an intrinsic property of resident corneal cells rather than systemic immune components, cornea buttons were removed following inoculation and placed in overnight culture in vitro. Like the findings above, corneal buttons of nude mice showed decreased chemokine production compared with those of BALB/c mice (Fig. 6E). Corresponding to the fact that IL-17-neutralized mice became insensitive to CaK induction, the inoculated corneas of anti-IL-17-treated mice had reduced production of above chemokines compared with isotype control antibody-treated mice (Supporting Information Fig. 6). Our results indicated that reduced chemokine production is correlated with CaK resistance in nude mice.