Chai J Y, Kook J, Guk S M, Chang Y P, Yun C K
Department of Parasitology, Seoul National University College of Medicine, Korea.
Korean J Parasitol. 1997 Jun;35(2):79-85. doi: 10.3347/kjp.1997.35.2.79.
Toxoplasma gondii, an intracellular protozoan infecting many kinds of eukaryotic cells, has been used to experimentally infect macrophages, epithelial cells, fibroblasts, and various cancer cells, but rarely T and B lymphocytes or granulocytes. The present study was performed to determine the susceptibility of murine (BALB/c or CBA) splenic T and B lymphocytes, and granulocytes to infection with T. gondii RH tachyzoites. The ultrastructure of the infected host cells was observed by TEM, and the degree of intracellular parasite proliferation was quantified using 3H-uracil uptake assay. At 24 hrs post-culture, the host cell cytoplasm was found to contain 1 or 2, or a maximum of 7-8 tachyzoites. Infected T lymphocytes demonstrated a peripherally displaced nucleus, a parasitophorous vacuole enveloping the parasite, and an increased number of mitochondria. In B lymphocytes infected with tachyzoites, RER was not well developed compared to uninfected B lymphocytes. Uninfected granulocytes contained many electron-dense granules, but T. gondii-infected granulocytes demonstrated a decreased number of granules. Based on the 3H-uracil uptake assay, the susceptibility of T and B lymphocytes, and granulocytes, to infection with T. gondii tachyzoites was fairly high irrespective of cell type and strain of mouse. This strongly suggests deterioration in the functioning of infected host immune cells.
刚地弓形虫是一种感染多种真核细胞的细胞内原生动物，已被用于实验性感染巨噬细胞、上皮细胞、成纤维细胞和各种癌细胞，但很少用于感染T和B淋巴细胞或粒细胞。本研究旨在确定小鼠（BALB/c或CBA）脾T和B淋巴细胞以及粒细胞对刚地弓形虫RH速殖子感染的易感性。通过透射电子显微镜观察感染宿主细胞的超微结构，并使用3H-尿嘧啶摄取试验定量细胞内寄生虫的增殖程度。培养24小时后，发现宿主细胞质中含有1个或2个，最多7-8个速殖子。受感染的T淋巴细胞表现出细胞核外周移位、包裹寄生虫的寄生泡以及线粒体数量增加。与未感染的B淋巴细胞相比，感染速殖子的B淋巴细胞中粗面内质网发育不良。未感染的粒细胞含有许多电子致密颗粒，但感染刚地弓形虫的粒细胞中颗粒数量减少。基于3H-尿嘧啶摄取试验，无论细胞类型和小鼠品系如何，T和B淋巴细胞以及粒细胞对刚地弓形虫速殖子感染的易感性都相当高。这强烈表明受感染宿主免疫细胞的功能恶化。
