An improved method for the isolation and characterization of rat intestinal intraepithelial lymphocytes and its application in a model of helminth infection (Trichinella spiralis)

The present study represents the development of an improved method for the isolation and characterization of rat intestinal intraepithelial lymphocytes (IEL) and its application to the examination of cells in Trichinella spiralis infection for which T helper cell IEL function in immunity has been suggested although not proven.; A method of IEL isolation has been developed that allows for the recovery of IEL with sufficient yield and purity to be useful for a variety of studies. The resulting rat IEL population was examined by flow cytometric analysis and was found to include cells of unique phenotypes, including CD8{dollar}alphaalphasp+{dollar} cells, {dollar}ydelta{dollar}TCR{dollar}sp+{dollar} cells, CD4{dollar}sp+{dollar}CD8{dollar}sp+{dollar}cells, CD8{dollar}sp+{dollar}CD45RC{dollar}sp-{dollar} cells, and a previously unreported population of class II MHC{dollar}sp+{dollar} IEL. Three color flow cytometric analysis of IEL identified CD8{dollar}sp+alphabeta{dollar}TCR{dollar}sp+{dollar} (and probably CD45RC{dollar}sp-){dollar} cells as the predominant class II MHC{dollar}sp+{dollar} subset.; Examination of IEL and mesenteric lymph node cells during Trichinella sprialis infection shows that {dollar}alphasb4{dollar} integrin levels are decreased on IEL and L-selectin levels are increased on MLNC on both days one and two post-infection. On day three post-infection an increase in CD4{dollar}sp+{dollar}CD45RC{dollar}sp+{dollar} IEL is detected and persists following expulsion of the parasite. IEL, which appear to be blocked from proliferation under normal circumstances, proliferate on day one post-infection whereas mesenteric lymph node cells do not proliferate. The significance of these alterations in lymphocyte phenotype during T. spiralis infection are unknown but in conjunction with published observations they imply a role for IEL in the immune response to T. spiralis. (Abstract shortened by UMI.)...