GAMMA-DELTA-TCR-IEL) IN REACTION AGAINST INTESTINAL NEMATODE TRICHINELLA-SPIRALIS( INTESTINAL INTRAEPITHELIAL LYMPHOCYTES (I)

To assess the gamma delta TCR T cells in the control of the timing of the mucosal response to enteric parasitic infections, we used C57BL mi ce, orally infected with 200 viable T. spiralis larvae. The small inte stine, spleens and Peyer's patches (PP) were excised on 1, 4, 7, 14, 2 1 and 29 postinfection days (p.i.) for immunophenotyping and histologi cal studies. Uninfected mice served as control. Characterization of is olated lymphocytes of C57BL control mice, confirmed that T cell immuno phenotype differs in spleen, PP and i-IEL. Practically all i-IEL were CD3(+) cells (83%). In addition, most of the i-IEL expressed Ly-2 (65% ). Among the i-IEL, the level of gamma delta TCR+ cells was significan tly higher (29%) than that found in spleen (3%) and PP (3%). The expre ssion was high on CD3(+) and Ly-2(+) (26 and 21%, respectively) and lo w on L3T4(+) i-IEL (<1%). During T. spiralis infection alpha beta TCR( +)CD3(+), gamma delta TCR(+)CD3(+) and gamma delta TCR(+)Ly-2(+) i-IEL increased on day 4 and 7. However, infected mice displayed a reductio n in I-IEL number from 14 to 29 p.i. day. At the same time the proport ion of gamma delta TCR on spleen Ly-2(+) and on PP CD3(+) and Ly-2(+) cells increased on 14 and 21 p.i. day. Adult worms were expelled from the gut by day 14. Thus, the kinetics of gamma delta TCR+ i-IEL, but n ot spleen and PP gamma delta TCR, corresponded to the kinetics of worm expulsion in C57BL mice. Most murine i-IEL of the gamma delta T cell lineage tend to be cytolytic when activated. We speculated that gamma delta T cells of i-IEL during the early stages of infection recognize and eliminate damaged epithelial cells generated by parasite antigens, simultaneously accelerating the worm expulsion, (C) 1998 Elsevier Sci ence Ltd. All rights reserved.