Analysis of T cell populations and IL-3 mRNA expression in mesenteric lymph node cells and intestinal intraepithelial lymphocytes in Strongyloides ratti-infected mice.

T cell populations and IL-3 mRNA expression were analysed in mesenteric lymph node cells and intestinal intraepithelial lymphocytes (IEL) in Strongyloides ratti-infected mice. On days 7 and 12 post-infection, 2.6 times as many mesenteric lymph node cells were present in S. ratti-infected mice compared with uninfected mice. Although the percentages of CD3+, CD4+ and CD8+ cells decreased during infection, the absolute numbers of these cell types increased on day 7 due to an overall increase in the mesenteric lymph node cell number. The CD4/CD8 ratio in IEL was increased on day 5, whereas no significant change in the CD4/CD8 ratio was observed in the mesenteric lymph node cells. Expression of IL-3 mRNA, which is an important cytokine for the induction of murine mucosal mastocytosis and S. ratti-expulsion, was examined in mesenteric lymph nodes and IEL of uninfected and infected mice. IL-3 mRNA was detected in mesenteric lymph nodes of S. ratti-infected mice but not detected in the lymph nodes of uninfected mice. IL-3 mRNA was detected in IEL from both infected and uninfected mice with an 20-fold increase in expression in IEL of infected mice. Overall, IL-3 mRNA levels were higher in IEL than in mesenteric lymph nodes following S. ratti-infection. Expression of IL-4, IL-10, stem cell factor (SCF or c-kit ligand) and IFN-gamma mRNA was also examined in these two tissues. IL-10 mRNA was not detected in any tissue examined and IFN-gamma mRNA levels were unaltered as a result of an S. ratti-infection. Elevated expression of mRNA for SCF (5-fold) and IL-4 (20-fold) was observed in the mesenteric lymph nodes of infected mice. In contrast, SCF mRNA levels were similar in IEL of uninfected and infected animals and only a modest increase in IL-4 mRNA was observed in IEL of infected mice.