Lev B, Ward H, Keusch G T, Pereira M E
Science. 1986 Apr 4;232(4746):71-3. doi: 10.1126/science.3513312.
A lectin in Giardia lamblia was activated by secretions from the human duodenum, the environment where the parasite lives. Incubation of the secretions with trypsin inhibitors prevented the appearance of lectin activity, implicating proteases as the activating agent. Accordingly, lectin activation was also produced by crystalline trypsin and Pronase; other proteases tested were ineffective. When activated, the lectin agglutinated intestinal cells to which the parasite adheres in vivo. The lectin was most specific to mannose-6-phosphate and apparently was bound to the plasma membrane. Activation of a parasite lectin by a host protease represents a novel mechanism of host-parasite interaction and may contribute to the affinity of Giardia lamblia to the infection site.
蓝氏贾第鞭毛虫中的一种凝集素可被人体十二指肠（即该寄生虫生存的环境）的分泌物激活。将这些分泌物与胰蛋白酶抑制剂一起孵育可阻止凝集素活性的出现，这表明蛋白酶是激活剂。相应地，结晶胰蛋白酶和链霉蛋白酶也能产生凝集素激活作用；所测试的其他蛋白酶则无效。激活后，该凝集素可凝集寄生虫在体内粘附的肠道细胞。这种凝集素对6-磷酸甘露糖具有高度特异性，且显然与质膜结合。宿主蛋白酶对寄生虫凝集素的激活代表了一种宿主-寄生虫相互作用的新机制，可能有助于蓝氏贾第鞭毛虫对感染部位的亲和力。
