Masaru Tajima

Generation of colonic IgA-secreting cells in the caecal patch

Gut-associated lymphoid tissues are responsible for the generation of IgA-secreting cells. However, the function of the caecal patch, a lymphoid tissue in the appendix, remains unknown. Here we analyse the role of the caecal patch using germ-free mice colonized with intestinal bacteria after appendectomy. Appendectomized mice show delayed accumulation of IgA(+) cells in the large intestine, but not the small intestine, after colonization. Decreased colonic IgA(+) cells correlate with altered faecal microbiota composition. Experiments using photoconvertible Kaede-expressing mice or adoptive transfer show that the caecal patch IgA(+) cells migrate to the large and small intestines, whereas Peyers patch cells are preferentially recruited to the small intestine. IgA(+) cells in the caecal patch express higher levels of CCR10. Dendritic cells in the caecal patch, but not Peyers patches, induce CCR10 on cocultured B cells. Thus, the caecal patch is a major site for generation of IgA-secreting cells that migrate to the large intestine.

Invention of a forced-air-ventilated micro-isolation cage and rack system Environment within cages: temperature and ammonia concentration

Abstract Isolator caging systems provide individual animal microenvironments and can be useful in the research setting. This caging system may be required to provide a barrier for specific-pathogen-free rodents at the cage level. In this study, we designed a forced-air ventilation system (FVMIS) and evaluated its ability to control such environmental factors as temperature and ammonia concentration within cages. We found that the FVMIS was capable of controlling the temperature uniformly and accurately while housing rats. In addition, microenvironmental ammonia concentrations, determined daily from days 1 through 16, showed a delayed rise in ammonia concentration by at least 4 days in FVMIS cages compared to non-ventilated control cages. This suppression of ammonia allows for a reduction in the frequency of cage changes.