Chiappino M L, Nichols B A, O'Connor G R
J Protozool. 1984 May;31(2):288-92. doi: 10.1111/j.1550-7408.1984.tb02963.x.
Scanning electron microscopy confirmed our previous finding that toxoplasmas actively invade mouse peritoneal cells that are inhibited from phagocytosis. The parasites entered cells with the conoid end first and sometimes showed a counter-clockwise torsion of the body during invasion. Counter-clockwise torsion was also noted in free toxoplasmas. Host-cell responses to active invasion varied with experimental conditions and with the type of host cell. Under adverse culture conditions for phagocytosis, normal macrophages formed rudimentary filopodia or lamellipodia around the tips of invading toxoplasmas; macrophages subjected to hyperthermia before similar incubation with toxoplasmas showed little or no response to invasion. Normal and heat-treated lymphocytes showed little surface reaction to invasion, but occasionally a flocculent collar was seen around the tip of an invading toxoplasma. Scanning electron microscopy provides clues to possible mechanisms of toxoplasma locomotion and host-cell invasion.
扫描电子显微镜证实了我们之前的发现，即弓形虫能主动侵入抑制吞噬作用的小鼠腹膜细胞。寄生虫以锥状端先进入细胞，在侵入过程中身体有时会逆时针扭转。在游离的弓形虫中也观察到逆时针扭转。宿主细胞对主动侵入的反应因实验条件和宿主细胞类型而异。在不利于吞噬作用的培养条件下，正常巨噬细胞在侵入的弓形虫尖端周围形成原始的丝状伪足或片状伪足；在与弓形虫进行类似孵育之前接受过热处理的巨噬细胞对侵入几乎没有反应。正常和热处理的淋巴细胞对侵入几乎没有表面反应，但偶尔在侵入的弓形虫尖端周围可见絮状环。扫描电子显微镜为弓形虫运动和宿主细胞侵入的可能机制提供了线索。
