It has been known for many years that Trichinella spiralis initiates infection by penetrating the columnar epithelium of the small intestine; however, the mechanisms used by the parasite in the establishment of its intramulticellular niche in the intestine are unknown. Although the previous observations indicated that invasion also occurs in vitro when the infective larvae are inoculated onto cultures of intestinal epithelial cells (e.g., human colonic carcinoma cell line Caco-2, HCT-8), a normal readily manipulated in vitro model has not been established because of difficulties in the culture of primary intestinal epithelial cells (IECs). In this study, we described a normal intestinal epithelial model in which T. spiralis infective larvae were shown to invade the monolayers of normal mouse IECs in vitro. The IECs derived from intestinal crypts of fetal mouse small intestine had the ability to proliferate continuously and express specific cytokeratins as well as intestinal functional cell markers. Furthermore, they were susceptible to invasion by T. spiralis. When inoculated onto the IEC monolayer, infective larvae penetrated cells and migrated through them, leaving trails of damaged cells heavily loaded with T. spiralis larval excretory-secretory (ES) antigens which were recognized by rabbit immune sera on immunofluorescence test. The normal intestinal epithelial model of invasion mimicking the natural environment in vivo will help us to further investigate the process as well as the mechanisms by which T. spiralis establishes its intestinal niche.
References
[1]
Ali Khan Z (1966) The postembryonic development of Trichinella spiralis with special reference to ecdysis. J Parasitol 52: 248–259.
[2]
Kozek WJ (1971) The molting pattern in Trichinella spiralis. I. A light microscope study. J Parasitol 57: 1015–1028.
[3]
Despommier DD (1983) Biology. In: Campbell WC, editor. Trichinella and Trichinosis. Plenum Press, New York. 75 p.
[4]
Martinez J, Rodriguez-Caabeiro F (2005) Relationship between heat shock protein levels and infectivity in Trichinella spiralis larvae exposed to different stressors. Parasitol Res 97: 213–218.
[5]
Wright KA (1979) Trichinella spiralis: an intracellular parasite in the intestinal phase. J Parasitol 65: 441–445.
[6]
Wright KA, Weidman E, Hong H (1987) The distribution of cells killed by Trichinella spiralis in the mucosal epithelium of two strains of mice. J Parasitol 73: 935–939.
[7]
ManWarren T, Gagliardo L, Geyer J, McVay C, Pearce-Kelling S, et al. (1997) Invasion of intestinal epithelia in vitro by the parasitic nematode Trichinella spiralis. Infect Immun 65: 4806–4812.
[8]
McVay CS, Bracken P, Gagliardo LF, Appleton J (2000) Antibodies to tyvelose exhibit multiple modes of interference with the epithelial niche of Trichinella spiralis. Infect Immun 68: 1912–1918.
[9]
Gagliardo LF, McVay CS, Appleton JA (2002) Molting, ecdysis, and reproduction of Trichinella spiralis are supported in vitro by intestinal epithelial cells. Infect Immun 70: 1853–1859.
[10]
Butcher BA, Gagliardo LF, ManWarren T, Appleton JA (2000) Larvae-induced plasma membrane wounds and glycoprotein deposition are insufficient for Trichinella spiralis invasion of epithelial cells. Mol Biochem Parasitol 107: 207–218.
[11]
Crum ED, Despommier DD, McGregor DD (1977) Immunity to Trichinella spiralis. I. Transfer of resistance by two classes of lymphocytes. Immunology 33: 787–795.
[12]
Hauft SM, Sweetser DA, Rotwein PS, Lajara R, Hoppe PC, et al. (1989) A transgenic mouse model that is useful for analyzing cellular and geographic differentiation of the intestine during fetal development. J Biol Chem 264: 8419–8429.
[13]
Tao R, Han Y, Chai J, Li D, Sun T (2010) Isolation, culture, and verification of human sweat gland epithelial cells. Cytotechnology 62: 489–495.
[14]
Carmichael J, DeGraff WG, Gazdar AF, Minna JD, Mitchell JB (1987) Evaluation of a tetrazolium-based semiautomated colorimetric assay: assessment of chemosen -sitivity testing. Cancer Res 47: 936–942.
[15]
Fernandes MI, Galv？o LC, Bortolozzi MF, Oliveira WP, Zucoloto S, et al. (1997) Disaccharidase levels in normal epithelium of the small intestine of rats with iron-deficiency anemia. Braz J Med Biol Res 30: 849–854.
[16]
Yamada K, Sato K, Morishita S, Kaminogawa S, Totsuka M (2009) Establishment of a primary culture method for mouse intestinal epithelial cells by organ culture of fetal small intestine. Biosci Biotechnol Biochem 73: 1849–1855.
[17]
Liu Z, Zhang P, Zhou Y, Qin H, Shen T (2010) Culture of human intestinal epithelial cell using the dissociating enzyme thermolysin and endothelin-3. Braz J Med Biol Res 43: 451–459.
[18]
Abud HE, Watson N, Heath JK (2005) Growth of intestinal epithelium in organ culture is dependent on EGF signalling. Exp Cell Res 303: 252–262.
[19]
Shimizu M, Minakuchi K, Tsuda A, Hiroi T, Tanaka N, et al. (2001) Role of stem cell factor and c-kit signaling in regulation of fetal intestinal epithelial cell adhesion to fibronectin. Exp Cell Res 266: 311–322.
[20]
Quaroni A, Wands J, Trelstad RL, Isselbacher KJ (1979) Epithelioid cell cultures from rat small intestine. Characterization by morphologic and immunologic criteria. J Cell Biol 80: 248–265.
[21]
Perreault N, Jean-Fran？ois B (1996) Use of the dissociating enzyme thermolysin to generate viable human normal intestinal epithelial cell cultures. Exp Cell Res 224: 354–364.
[22]
Hotez P, Cappello M, Hawdon J, Beckers C, Sakanari J (1994) Hyaluronidases of the gastrointestinal invasive nematodes Ancylostoma caninum and Anisakis simplex: possible functions in the pathogenesis of human zoonoses. J Infect Dis 170: 918–926.
[23]
Drake L, Korchev Y, Bashford L, Djamgoz M, Wakelin D, et al. (1994) The major secreted product of the whipworm, Trichuris, is a pore-forming protein. Proc Biol Sci 257: 255–261.
[24]
Bruce RG (1970) Structure of the esophagus of the infective juvenile and adult Trichinella spiralis. J Parasitol 56: 540–549.
[25]
Wang SW, Wang ZQ, Cui J (2011) Protein change of intestinal epithelial cells induced in vitro by Trichinella spiralis infective larvae. Parasitol Res 108: 593–599.
[26]
Theodoropoulos G, Petrakos G (2010) Trichinella spiralis: differential effect of host bile on the in vitro invasion of infective larvae into epithelial cells. Exp Parasitol 126: 441–444.
