Rasschaert Kristien, Devriendt Bert, Favoreel Herman, Goddeeris Bruno M, Cox Eric
Laboratory of Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
Vet Immunol Immunopathol. 2010 Oct 15;137(3-4):243-50. doi: 10.1016/j.vetimm.2010.05.016. Epub 2010 Jun 8.
Enterotoxigenic Escherichia coli (ETEC) cause severe diarrhea in neonatal and recently weaned piglets. Previously, we demonstrated that oral immunization of F4 receptor positive piglets with purified F4 fimbriae induces a protective F4-specific intestinal immune response. However, in F4 receptor negative animals no F4-specific immune response can be elicited, indicating that the induction of an F4-specific mucosal immune response upon oral immunisation is receptor-dependent. Although F4 fimbriae undergo transcytosis across the intestinal epithelium in vivo, the endocytosis pathways used remain unknown. In the present study, we characterized the internalization of F4 fimbriae in the porcine intestinal epithelial cell line IPEC-J2. The results in the present study demonstrate that F4 fimbriae are internalized through a clathrin-dependent pathway. Furthermore, our results suggest that F4 fimbriae are transcytosed across differentiated IPEC-J2 cells. This receptor-dependent transcytosis of F4 fimbriae may explain the immunogenicity of these fimbriae upon oral administration in vivo.
产肠毒素大肠杆菌（ETEC）可导致新生仔猪和刚断奶仔猪严重腹泻。此前，我们证明用纯化的F4菌毛对F4受体阳性仔猪进行口服免疫可诱导产生保护性的F4特异性肠道免疫反应。然而，在F4受体阴性的动物中无法引发F4特异性免疫反应，这表明口服免疫时F4特异性黏膜免疫反应的诱导是受体依赖性的。尽管F4菌毛在体内可通过肠上皮细胞进行转胞吞作用，但所使用的内吞途径仍不清楚。在本研究中，我们对猪肠道上皮细胞系IPEC-J2中F4菌毛的内化进行了表征。本研究结果表明，F4菌毛通过网格蛋白依赖性途径内化。此外，我们的结果表明F4菌毛可通过分化的IPEC-J2细胞进行转胞吞作用。F4菌毛这种受体依赖性的转胞吞作用可能解释了这些菌毛在体内口服给药时的免疫原性。
