Moore-Lai Deborah, Rowland Edwin C
Molecular and Cellular Biology Program, Tropical Disease Institute, Ohio University College of Osteopathic Medicine, Athens, Ohio 45701, USA.
J Parasitol. 2004 Feb;90(1):85-91. doi: 10.1645/GE-123R1.
Trypanosoma cruzi is the causative agent of Chagas disease, which is characterized by acute and chronic phases. During the former, parasitemia rises dramatically, then decreases significantly during the chronic phase. Immune mechanisms responsible for the parasitemia reduction have not been thoroughly elucidated. The goal of the present study was to further characterize the immune response during chronic infection. Previously, we described antiegressin, an antibody in sera from chronically infected mice. The in vitro presence of antiegressin inhibits parasite egress from infected host cells. Antiegressin appears by day 14 of an in vivo infection and is maintained through at least day 280 postinfection. The in vitro functional activity of antiegressin is initiated late in the 4-6 days intracellular growth cycle of T. cruzi; antiegressin may be added at day 4, inhibiting parasite release at day 5. Immunocytochemical staining using antineuraminidase demonstrates the presence of mature parasites inside host BALB/c fibroblasts grown in the presence of antiegressin. These results demonstrate the ability of antiegressin to inhibit emergence of developmentally mature trypomastigotes from infected host cells late in their intracellular growth cycle. We believe this antibody plays an important and novel role in achieving the low-parasitemia characteristic of chronic Chagas disease.
克氏锥虫是恰加斯病的病原体，该病具有急性期和慢性期。在急性期，寄生虫血症急剧上升，然后在慢性期显著下降。导致寄生虫血症降低的免疫机制尚未完全阐明。本研究的目的是进一步表征慢性感染期间的免疫反应。此前，我们描述了抗逸出素，这是一种来自慢性感染小鼠血清中的抗体。抗逸出素在体外的存在会抑制寄生虫从受感染的宿主细胞中逸出。抗逸出素在体内感染后第14天出现，并至少在感染后280天持续存在。抗逸出素的体外功能活性在克氏锥虫4至6天的细胞内生长周期后期开始；抗逸出素可在第4天添加，抑制第5天的寄生虫释放。使用抗神经氨酸酶的免疫细胞化学染色显示，在抗逸出素存在的情况下生长的宿主BALB/c成纤维细胞内存在成熟寄生虫。这些结果证明了抗逸出素在细胞内生长周期后期抑制发育成熟的锥鞭毛体从受感染宿主细胞中逸出的能力。我们认为这种抗体在实现慢性恰加斯病的低寄生虫血症特征方面发挥着重要且新颖的作用。
