Carlisle M S, McGregor D D, Appleton J A
James A. Baker Institute for Animal Health, Dept. of Microbiology, Immunology and Parasitology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.
Immunology. 1991 Nov;74(3):552-8.
When an IgG2c monoclonal antibody specific for Trichinella spiralis muscle stage larvae was cleaved with pepsin to yield F(ab')2 fragments, the latter retained their capacity to cause mucus entrapment and rapid expulsion of larvae from the intestines of suckling rats. When fed to pups, the F(ab')2 fragments of this antibody and the F(ab')2 fragments of a similarly prepared IgG2a antibody caused mucus entrapment of muscle larvae (ML), demonstrating that trapping is not dependent upon the Fc region of the antibody molecule. Despite the fact that these two antibodies had similar specificities and that their F(ab')2 fragments caused larval entrapment in mucus, F(ab')2 fragments of the IgG2a antibody failed to protect rat pups. Fragments of the IgG2c antibody caused rapid expulsion when injected into pups, but the distribution of larvae was dramatically different from when the fragments were delivered orally. These results indicate that entrapment of T. spiralis in mucus is not in itself the cause of the expulsion. The more likely possibility is that antibody impedes a function of Trichinella spiralis that is related to the capacity of the parasite to reside in its epithelial niche.
当用胃蛋白酶裂解针对旋毛虫肌幼虫的IgG2c单克隆抗体以产生F(ab')2片段时，后者保留了其导致黏液截留并使幼虫从乳鼠肠道快速排出的能力。当将该抗体的F(ab')2片段和以类似方式制备的IgG2a抗体的F(ab')2片段喂给幼崽时，它们会导致肌幼虫（ML）被黏液截留，这表明截留并不依赖于抗体分子的Fc区域。尽管这两种抗体具有相似的特异性，且它们的F(ab')2片段会导致幼虫被截留于黏液中，但IgG2a抗体的F(ab')2片段未能保护幼鼠。IgG2c抗体的片段注入幼鼠时会导致快速排出，但幼虫的分布与经口给药时显著不同。这些结果表明，旋毛虫被截留于黏液本身并非排出的原因。更有可能的情况是，抗体阻碍了旋毛虫的一种功能，该功能与寄生虫在其上皮小生境中生存的能力有关。
