Differential expression of CD43 isoforms on murine T cells and their relationship to acute intestinal graft versus host disease: studies using enhanced-green fluorescent protein transgenic mice

Three mAb (R2/60, S7 and 1B11) were used to study the expression of murine CD43 on peripheral T cells and intestinal intraepithelial lymphocytes (IEL) from normal mice, and from mice during acute graft versus host disease (GVHD). In the spleen, essentially all T cells expressed the R2/60 and S7 antigens, whereas the 1B11 antigen was expressed on about half of the CD8(+) cells and approximately 15% of CD4(+) T cells. Interestingly, a significant proportion of resting splenic B cells expressed the 1B11 and R2/60 antigens, but not the S7 antigen. The majority of IEL expressed R2/60 antigen; however, the S7 and 1B11 markers were differentially expressed on CD8alpha, CD8beta, TCRalphabeta and TCRgammadelta cells. Immunoprecipitation and Western blotting analyses identified characteristic 115 and 130 kDa reactive components from IEL lysates with mAb S7 and 1B11 respectively, and reactivity to both molecular entities by mAb R2/60. During acute intestinal GVHD induced by injecting CB6F(1) athymic nude mice with spleen cells from C57BL/6 enhanced-green fluorescent protein transgenic mice, 80-90% of donor T cells in the intestine epithelium expressed all CD43 isoforms; however, the level of expression of the 130 kDa CD43 antigen increased significantly and the level of the 115 kDa antigen decreased on GVHD donor T cells compared to cells at the time of transfer. Using EL4 cells, a similar shift in the expression of CD43 isoforms occurred experimentally following treatment with neuraminidase, suggesting that the type of CD43 isoform expressed on T cells is strongly influenced by conditions which affect membrane charge. The significance of these findings for intestinal immunopathology is discussed.