干扰素γ对小鼠巨噬细胞株RAW264．7吞噬、杀伤阿萨希毛孢子菌的影响

Effects of interferon-gamma on the phagocytosis and killing activity of a murine macrophage cell line RAW264.7 against Trichosporon asahii

目的研究干扰素1对小鼠巨噬细胞株RAW264．7吞噬、杀伤阿萨希毛孢子菌（zasahii）的作用，探讨干扰素γ临床治疗zasahff感染的可能性。方法不同浓度（10、100、1000u/ml）干扰素1与RAW264．7细胞共孵育18h后，分别与zasahff临床株共培养45min、4h，以不加干扰素γ组为对照组。45min后在显微镜下观察RAW264．7细胞吞噬zasahff的情况，计数吞噬个数及计算吞噬率。4h后检测RAW264．7细胞的杀伤活性，即检测zasahfi的菌落形成单位（cfu／m1），计算生长抑制率。采用SPSS16．0软件进行统计学分析，作方差齐性检验后，用单因素方差分析（ANOVA）中的Bonferroni法进行各组均数间的两两比较。结果10、100、1000U／ml干扰素1组小鼠巨噬细胞株RAW264．7吞噬zasahfi的个数分别为25．12±1．81、35．88±3．56、52．12±3．23，吞噬率依次为25．12％、35．88％、52．12％，与对照组吞噬Zasahfi的个数（13．62±2．39）比较，差异均有统计学意义（P〈0．01）；RAW264．7细胞对zasahii的杀伤活性分别为（58，62±4．89）x500、（45．50±3．02）×500、（34．62±4．24）X500cfu／ml，生长抑制率依次为25．21％、41．95％、55．83％，RAW264．7细胞的杀伤活性与对照组（68．12±3．39）×500cfu／ml比较，差异均有统计学意义（P〈0．01）。结论干扰素γ呈剂量依赖性增强小鼠巨噬细胞株RAW264．7吞噬、杀伤zasahii的作用。

Objective To determine the effect of interferon-gamma （IFN-γ） on the phagocytosis and killing activity of a murine macrophage cell line RAW264.7 against T. asahii, and to estimate the possibility of treating T. asahii infection with IFN-γ. Methods T. asahii was cultured with or without the presence of different concentrations （10, 100, 1000 U/ml） of IFN-γ for 18 hours followed by the incubation with RAW264.7 cells for different durations. After additional culture for 45 minutes, the number of T. asahii cells phagocytosed by RAW264.7 cells was counted under an inverted microscope, and the rate of phagocytosis was calculated. The number of colony forming units of T. asahii per milliliter （cfu/ml） was counted after 4-hour additional culture and the growth inhibition rate was determined. Data were processed by the SPSS 16.0 software, and comparisons of parameters between these groups were done by Bonferroni method and analysis of variance after homogeneity test of variance. Results The number of phagocytosed T. asahii cells was 25.12±1.81, 35.88 ± 3.56, 52.12± 3.23, with the phagocytosis rate being 25.12%, 35.88% and 52.12%, respectively in RAW264.7 cells incubated with IFN-γ of 10, 100, 1000 U/ml, significantly different from that in untreated RAW264.7 cells （13.62 ± 2.39, 13.62%, all P 〈 0.01 ）. The colony forming units of T. asahii per ml after incubation with untreated RAW264.7 cells differed significantly from those after incubation with IFN-γ （10, 100, 1000 U/ml）-treated RAW264.7 cells （（68.12±3.39） x 500 vs. （58.62±4.89） x 500, （45.50 ± 3.02） x 500 and （34.62 ± 4.24） x 500, all P〈 0.01）, with the growth inhibition rate being 25.21%, 41.95% and 55.83% respectively for RAW264.7 cells incubated with IFN-γ of 10, 100, 1000 U/ml. Statistical differences were also observed in the killing activity between RAW264.7 cells incubated with different concentrations of IFN-γ （all P 〈 0.01）. Conclusion IFN-γ （10-1000 U/ml） may enhance the phagocytosis and killing activity of RAW264.7 cells against T. asahii in a concentration-dependent manner.