这些曲霉菌引起的疾病目前致死率很高(图)
最新的发表在《Journal of Medical Microbiology》杂志的一项研究发现,通过向老鼠体内注射面包酵母,能有效抵抗致病性真菌的感染,例如曲霉菌。
由于目前临床上对于曲霉菌感染的治疗能力非常有限,因此这项研究的发现对于未来开发能有效帮助免疫系统受损或低下的病人抵抗真菌感染的疫苗具有重要意义。
来自加利福利亚医学院、圣克拉拉山谷医学院和斯坦福大学的科学家们通过给小鼠注射三次(每周一次)灭活后的面包酵母后,发现接种疫苗后的小鼠能有效抵抗高剂量的曲霉菌感染。
曲霉菌占空气中真菌的12%左右,主要以枯死的植物、动物的排泻物及动物尸体为营养源,为寄生于土壤中的腐生菌。其形态特征是在分生孢子的头部有一个顶囊。曲霉菌对于免疫力低下的个体而言危害非常大。它通常被人吸入到肺中,然后很快扩散到其他组织器官,如脑部、肝脏和肾脏,引起严重的器官功能失常。因为目前没有有效的治疗方法,这种真菌引起的疾病的致死率极高。
研究小组的成员通过在小鼠体内注射一种常见的面包酵母来抵抗曲霉菌的感染。他们还发现如果这种酵母的表面含有的曲霉菌表面分子蛋白越多,抵抗曲霉菌的能力就越强。该论文的通讯作者David A. Stevens博士说道:“我们的结果表明该酵母的保护成分主要分布在细胞表面。此外,我们还发现它能有效抵御其它三种引起人类疾病的真菌的感染,包括假丝菌、隐球菌和球孢子菌。”
面包酵母现在正被其它研究小组用于临床试验,且目前还很安全。Stevens博士说道:“研究至今,我们和之前其他科学家的研究都表明了酵母疫苗能有效抵御几乎所有的致病性真菌感染人体。因此我们相信这种疫苗在未来临床上有着很大的应用前景,它能大大降低那些由于免疫功能低下而感染上曲霉菌病人的死亡率。当然,给这些身体免疫机能本身受损的个体接种疫苗是一个巨大的挑战,并且这些疫苗一定会对一些病人产生副作用,比如说移植受者、接受化疗的白血病患者和诊断有实体肿瘤的患者。” (生物探索 Jun译)
生物探索推荐英文论文原文摘要:
Saccharomyces as a vaccine against systemic aspergillosis: 'the friend of man' a friend again?
The mortality of clinical Aspergillus infections necessitates consideration of the utility of a vaccine. We have found that Saccharomyces species can act as a protective vaccine against a lethal systemic Aspergillus infection, and describe experiments optimizing a subcutaneous regimen with killed yeast. Three injections of 2.5 mg given a week apart, 2 weeks prior to challenge, consistently, significantly, provided survival protection and reduction of infection in organs in survivors. The protection was independent of the strain of Saccharomyces, and possibly even the species, and could be demonstrated in several inbred (including C′-deficient) and outbred mouse strains. The protective moiety(ies) appeared to reside in the cell wall and was resistant to 100 °C, but not to protease or formalin. Alum potentiated the protection. The protection was comparable or superior to that of several Aspergillus-specific preparations described in the literature. Other studies have indicated that heat-killed Saccharomyces can protect against infection with at least three other fungal genera, raising the possibility of development of a panfungal vaccine, and such a vehicle has been studied in clinical trials, without dose-limiting toxicity.