No abstract

A comparison of immune responses to infection between groups of B10.BR mice infected with different strains of T. muris, S strain (isolated in Sobreda, Portugal), E strain (isolated in Edinburgh), and E-J strain (originally E strain, which has been maintained in our laboratory, Japan), was performed. In mice infected with E and E-J strains, most of the worms were expelled by day 32 after infection, though the expulsion was faster in E-J strain-infected mice. In contrast, no expulsion was observed in S strain-infected mice by day 32 and egg production occurred on day 32. IL-4 production occurred in concanavalin A (Con-A)-stimulated mesenteric lymph node cells (MLNC) from B10.BR mice infected with E and E-J strains, whereas no IL-4 production was observed in S strain-infected mice. IL-4 production did not occur in normal mice. In comparison with normal mice, high levels of IFN-gamma production by Con A-stimulated MLNC were detected in mice infected with every strain of T. muris. IFN-gamma production in S strain-infected mice was greater, occurred earlier and was more persistent than in mice infected with E and E-J strains. IgG1 and IgG2a antibodies to T. muris excretory/ secretory antigens were observed in B10.BR mice infected with every strain of T. muris. Antibody production showed similar kinetics. These differences in the expulsion kinetics and IL-4 production in B10.BR mice infected with S, E, and E-J strains suggest the involvement of IL-4 in protection against T. muris infection, and confirm the previous conclusion by Else et al.

The role of CD4+ and CD8+ T cells in protective immunity to Trichuris muris was studied in CD4+ or CD8+ or both CD4+ and CD8+ T cell-depleted BALB/c mice. To assess in vivo depletion of T-cell subsets, CD4+ and CD8+ T cells in the Peyer's patches, the mesenteric lymph nodes (MLN), and the spleens of mice treated with T cell-specific monoclonal antibodies (MoAbs) were analysed by FACS. CD4+ T cells were selectively depleted in mice injected with anti-CD4 MoAb i.p. and injection of anti-CD8 MoAb resulted in selective depletion of CD8+ T cells. The expulsion of T. muris was inhibited in CD4+ T cell-depleted mice and numerous worms were detected in the large intestine on days 14 and 21 after infection, although no suppression of protective immunity to T. muris was observed in CD8+ T cell-depleted mice. Moreover, there was no difference in suppression of protective immunity to T. muris between CD4+ T cell-depleted and both CD4+ and CD8+ T cells play a central role in protective immunity to T. muris infection.

We reported earlier that RUNX3 is expressed in human and mouse gastrointestinal tract (GIT) epithelium and that it functions as a tumor suppressor in gastric and colorectal tissues. However, there have been conflicting reports describing the absence of Runx3 in GIT epithelial cells. A part of the controversy may be derived from the use of a specific antibody by other groups (referred to as G-poly). Here, we show further evidence to support our earlier observations and provide a possible explanation for this apparent controversy. We generated multiple anti-RUNX3 monoclonal antibodies and found that RUNX3 antibodies recognizing the RUNX3 N-terminal region (residues 1-234) react with RUNX3 in gastric epithelial cells, whereas those recognizing the C-terminal region (beyond residue 234) did not. G-poly primarily recognizes the region beyond 234 and hence, is unable to detect Runx3 in this tissue.