MUCOSAL MAST-CELL PROLIFERATION FOLLOWING NORMAL AND HETEROTOPIC INFECTIONS OF THE NEMATODE NIPPOSTRONGYLUS-BRASILIENSIS IN RATS

Infections of intestinal nematodes induce the T cell-dependent prolife ration of intestinal mucosal mast cells (MMC). To examine whether nema tode-induced MMC proliferation is affected by the site of infestation, adult-stage nematode Nippostrongylus brasiliensis (NB) was transplant ed into the normal infection site, the duodenum, or into heterotopic s ites, the peritoneal cavity (i.p.) or subcutaneous tissue (s.c.), of r ats. Two weeks after duodenal inoculation, MMC numbers in the small in testine had increased 6.5-fold. In contrast, i.p. and s.c. inoculation induced only slight increases of intestinal MMC. After i.p. inoculati on, worm granulomas developed in the connective tissues adhering to st omach and duodenum, and large numbers of mast cells appeared around th e granulomas. The majority of the latter mast cells showed histochemic al features similar to MMC: they were formalin sensitive, berberine su lfate(-), alcian blue(+)/safranine(-), and rat mast cell protease (RMC P) II+. After s.c. inoculation, worm granulomas developed at the inocu lation site, but the number of mast cells around the granulomas was no t significantly increased. These results suggest that intense prolifer ation of MMC or MMC-like cells is induced only by the infections on mu cosa or in mucosa-associated tissues.