Folia Parasitologica 47[1] 55-59 (2000) | DOI: 10.14411/fp.2000.010

Analysis of intestinal intraepithelial lymphocyte populations in experimental Trichinella spiralis infection of mice

Frane Božić¹, Albert Marinculić², Emir Duraković²

¹ Department of Pharmacology and Toxicology, Veterinary Faculty, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia

² Department of Parasitology, Veterinary Faculty, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia

The potential role of intestinal intraepithelial lymphocytes (i-IELs) in the generation of host protective immunity after helminth infection was investigated using the Trichinella spiralis (Owen, 1835)/mouse model. In this study we found a significant rise of TCRγδ⁺ i-IELs (P < 0.001) concurrent with the jejunal goblet cells (GC) hyperplasia in T. spiralis-infected C57BL mice on day 4 p.i. However, no direct relationship between the kinetics of the increase in TCRγδ⁺ i-IELs and T. spiralis expulsion was observed in infected mice. Taken together, these results implicate that γδ i-IELs probably perform a unique functions related to the regulation of the GC proliferation accompanying T. spiralis gut infection. As is known, these TCRγδ⁺ i-IELs may release mediators or growth factors that in turn influence GC differentiation. With the use of dexamethason (DEX), a potent anti-inflammatory agent which also induces apoptotic cell death in i-IELs, we have confirmed that the expulsion of T. spiralis from the mouse gut is accompanied by an inflammatory response. Indeed, the GC are clearly involved in these phenomena, apparently under the regulation by TCRγδ⁺ i-IEL-mediated responses, since DEX abrogated GC proliferation in T. spiralis-infected C57BL mice and subsequently augmented adult worm burden. Our data also show that the rejection of adult worms starts concurrently with a significant increase in TCRαβ+ and CD8⁺ i-IELs (P < 0.05 and P <= 0.01, respectively), namely by day 7 p.i. At the same time, CD4⁺ cells significantly decreased (P < 0.05) in the intestinal epithelium of T. spiralis-infected, vs uninfected mice. These results may indicate that the TCRαβ⁺ and CD8⁺ i-IELs act as effectors of anti-T. spiralis defence reactions. The implications of these findings for the potential role of intestinal intraepithelial CD8⁺ and TCRαβ⁺ cells in the pathogenesis of the intestinal lesions during T. spiralis gut infection are discussed.

Keywords: Trichinella spiralis, goblet cells, i-IELs, gut

Received: May 3, 1999; Accepted: July 21, 1999; Published: March 1, 2000  Show citation