近日，微生物学系助理教授Kirsten Nielsen博士等研究人员发现巨细胞在感染过程中能保护真菌型隐球菌，他们的发现可能有助于开发新的方法来对付隐球菌引起的感染。
研究结果刊登在六月的Eukaryotic Cell杂志上。这项研究是由国家卫生部和明尼苏达大学医学院资助。
隐球菌是一种经常存在灰尘和污垢中的一种真菌，全世界每年有超过65万艾滋病患者因此种真菌而死亡。这也是化疗患者和器官移植的病人潜在的致命的危险。
Nielsen博士说：虽然大多数健康人能抗隐球菌感染，但真菌可导致那些薄弱的免疫系统抵抗性更弱，最终导致致命疾病。
隐球菌吸入时可引起肺部感染。这种感染可扩散到大脑和脑膜炎，引发大脑和脊椎致命性炎症。
Nielsen和Okagaki发现巨细胞或隐球菌细胞是正常细胞体积的十到二十倍，因为体积太大，人体的免疫系统无法摧毁这些细胞。
研究人员发现泰坦细胞的存在可以保护所有在部位的隐球菌细胞，即使是正常大小的隐球菌细胞。
Nielsen说：这就告诉我们，泰坦细胞是隐球菌在宿主与生物体之间相互作用以引起疾病的一个重要方面。这些研究结果将帮助我们找到新的方法来治疗隐球菌感染。（生物谷：Bioon.com）
Titan cells confer protection from phagocytosis in Cryptococcus neoformans infections
Laura H. Okagaki* and Kirsten Nielsen*
The human fungal pathogen Cryptococcus neoformans produces an enlarged “titan” cell morphology when exposed to the host pulmonary environment. Titan cells exhibit traits that promote survival in the host. Previous studies showed that titan cells are not phagocytosed and that increased titan cell production in the lungs results in reduced phagocytosis of cryptococcal cells by host immune cells. Here, the effect of titan cell production on host-pathogen interactions during early stages of pulmonary cryptococcosis was explored. The relationship between titan cell production and phagocytosis was found to be non-linear; moderate increases in titan cell production resulted in profound decreases in phagocytosis with significant differences occurring within the first 24 hours of the infection. Not only were titan cells themselves protected from phagocytosis, but titan cell formation also conferred protection from phagocytosis to normal size cryptococcal cells. Large particles introduced into the lungs were not phagocytosed, suggesting the large size of titan cells protects against phagocytosis. The presence of large particles was unable to protect smaller particles from phagocytosis, revealing that titan cell size alone is not sufficient to provide the observed cross-protection of normal size cryptococcal cells. These data suggest that titan cells play a critical role in establishment of the pulmonary infection by promoting the survival of the entire population of cryptococcal cells.
