Toxoplasma gondii is an obligate intracellular protozoan parasite that can infect all nucleated cells through active invasion. Some non-canonical pathways for T. gondii infection of macrophages have recently been reported. We report a new mode of T. gondii invasion using a time-lapse imaging system, in which T. gondii tachyzoites are engulfed by a tube-like structure on peritoneal macrophage phagosomes and then escape from the phagosomes. Escaped parasites re-invade macrophages through intercellular junctions between their apical end and host cell membranes. We call this invasion pathway of T. gondii “pseudopod-assisted invasion” (PAI). The completion of this invasion process depends on parasitic motility and secretion of adhesins from parasitic micronemes. Our results provide new information about T. gondii infection and establish another platform for studying interactions between T. gondii and macrophages.

弓形虫是专性的细胞内原生动物寄生虫，可通过主动入侵感染所有有核细胞。最近已经报道了弓形虫感染巨噬细胞的一些非经典途径。我们报告了一种使用延时成像系统入侵刚地弓形虫的新模式，其中刚地弓形体速殖子被腹膜巨噬细胞吞噬体上的管状结构吞没，然后从吞噬体中逸出。逃生的寄生虫通过其顶端与宿主细胞膜之间的细胞间连接重新侵入巨噬细胞。我们称此为弓形虫的入侵途径“伪足辅助入侵”（PAI）。该侵袭过程的完成取决于寄生虫的运动性和寄生的微nemes粘附素的分泌。我们的结果提供了有关弓形虫感染的新信息，并为研究弓形虫和巨噬细胞之间的相互作用建立了另一个平台。