A EUTHYMIC HAIRLESS MOUSE MODEL OF HELICOBACTER-PYLORI COLONIZATION AND ADHERENCE TO GASTRIC EPITHELIAL-CELLS IN-VIVO

The hairless mouse strain NS:Hr/ICR was examined as a potential small animal model of Helicobacter pylori colonization, adherence to gastric epithelial cells in vivo, and gastritis. Among several small animals tested, NS:Hr/ICR mice proved to be the most highly susceptible to H. pylori infection. Challenge with clinical isolates of H. pylori consis ting of either phenotype I or II (VacA and CagA positive and negative, respectively) resulted in colonization by mucus-resident and epitheli al cell-adherent bacterial populations. Cell-adherent bacteria resiste d 80 cycles of top-speed vortex washing and were recovered only by hom ogenization of serially washed glandular stomach tissue, indicating in timate association with the mucosal surface. Immunoperoxidase staining of paraffin sections of gastric tissue from infected mice revealed H. pylori antigens localized in the glandular region of the mucosa, with some colonized areas seen in the vicinity of submucosal mononuclear c ell infiltration. The latter inflammatory reaction was observed as a f unction of the H. pylori phenotype (only type I induced inflammation) and the challenge dose (only those mice challenged with 10(8) CFU or h igher showed the reaction). The NS:Hr/ICR strain of mice is a suitable miniature model of H. pylori infection and may prove useful in the qu est for an effcacious mode of treatment for this common infection in h umans.