OKAZAKI Ken-Ichi, ASAKURA Masahiro, SUGIMOTO Norihiko, HINENOYA Atsushi, YAMASAKI Shinji
Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Osaka, Japan.
J Vet Med Sci. 2009 Nov;71(11):1459-64. doi: 10.1292/jvms.001459.
It has been reported that administration of Candida albicans into mouse induces an antifungal activity in serum, which has been identified as transferrin. In the present study, we show that not only C. albicans, but also other fungus such as Cryptococcus neoformans or Aspergillus fumigatus similarly can induce an antifungal activity in mouse serum. This antifungal activity was inhibited by the addition of ferrous ion, indicating that the growth inhibition of C. albicans was due to deficiency of ferrous ion, which may be caused by transferrin. Indeed, addition of transferrin in an in vitro assay system using RPMI1640 culture medium inhibited the growth of C. albicans, C. neoformans or A. fumigatus. However, when C. albicans was grown in RPMI1640 medium with 10% fetal bovine serum (FBS), transferrin was unable to inhibit the growth of C. albicans, in sharp contrast, when C. albicans treated mouse serum was added instead of FBS, the growth of the organism was inhibited. Similar results were obtained when C. neoformans or A. fumigatus was used. Taken together, the results suggest that antifungal activity induced by C. albicans, C. neoformans or A. fumigatus was not due to transferrin but likely due to other unknown serum proteins, which may cut off the source of iron for the growth of these fungi.
据报道，将白色念珠菌接种到小鼠体内可诱导血清中的抗真菌活性，这种活性已被鉴定为转铁蛋白。在本研究中，我们发现不仅白色念珠菌，而且其他真菌如新型隐球菌或烟曲霉同样可以在小鼠血清中诱导抗真菌活性。这种抗真菌活性可被亚铁离子的添加所抑制，这表明白色念珠菌的生长抑制是由于亚铁离子的缺乏，而这可能是由转铁蛋白引起的。实际上，在使用RPMI1640培养基的体外测定系统中添加转铁蛋白可抑制白色念珠菌、新型隐球菌或烟曲霉的生长。然而，当白色念珠菌在含有10%胎牛血清（FBS）的RPMI1640培养基中生长时，转铁蛋白无法抑制白色念珠菌的生长，与之形成鲜明对比的是，当添加经白色念珠菌处理的小鼠血清而非FBS时，该菌的生长受到抑制。使用新型隐球菌或烟曲霉时也获得了类似结果。综上所述，结果表明白色念珠菌、新型隐球菌或烟曲霉诱导的抗真菌活性并非由于转铁蛋白，而是可能由于其他未知的血清蛋白，这些蛋白可能切断了这些真菌生长所需的铁源。
