Effect of fungus on expression of interferon-γ and interleukin-4 in natural killer cells

Abstract

Objective To investigate the effect of fungus Aspergillus fumigatus and Candida albicans on the expression of endocellular interferon-γ (IFN-γ) and interleukin-4 (IL-4) in cytokine-induced natural killer (NK) cells. Methods NK cells were cultured with Aspergillus fumigatus or Candida albicans by non-contact or direct-contact methods with a ratio of NK cells to fungus of 10∶1. The expressions of IFN-γ and IL-4 in NK cells were evaluated by flow cytometry after co-cultured for 6 h. Analysis of variance or SNK-q test was used to compare the expressions of IFN-γ and IL-4 among different groups. Results The IFN-γ expression rates in NK cells with direct contacting to Aspergillus fumigatus hyphae, or to different morphotypes of Candida albicans were (20.12±0.53)%, (20.69±0.34)% and (20.8±0.37)% respectively, while IFN-γ expression in NK cells with indirect contacting to fumigatus hyphae, or to different morphotypes of Candida albicans were (21.40±0.53)%, (20.57±1.09)% and (20.20±0.51)% respectively, and all were significantly higher than that in the blank group [(15.11±2.60)%, all P>0.05]. The IFN-γ expression rates in the Aspergillus fumigatus spores direct and indirect contacting groups were (14.33±0.98)% and (14.97±1.53)%, which were not of significant difference compared with the blank group (P>0.05). The IL-4 expression rates in NK cells with direct contacting to different morphotypes of Aspergillus fumigatus and Candida albicans were (1.25±0.06)%, (1.21±0.03)%, (1.22±0.46)% and (1.26±0.11)%, while those in indirect contacting groups were (1.21±0.06)%, (1.25±0.04)%, (1.27±0.03)% and (1.26±0.1)%, which were not of significant difference compared with the blank group [(1.23±0.05)%, all P>0.05]. Conclusion Fungus stimuli can reduce the secretion of IFN-γ in NK cells, but have not significant influence on the secretion of IL-4. Key words: Aspergillus fumigatus; Candida albicans; Natural killer T-cells; Interferon-γ; Interleukin-4