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 (GV HD), In the spleen, essentially all T cells expressed the R2/60 and S7 anti gens, whereas the 1B11 antigen was expressed on about half of the CD8(+) ce lls and similar to 15% of CD4(+) T cells. Interestingly, a significant prop ortion of resting splenic a cells expressed the 1B11 and R2/60 antigens, bu t not the S7 antigen. The majority of IEL expressed R2/60 antigen; however, the S7 and 1B11 markers were differentially expressed on CD8 alpha, CD8 be ta, TCR alpha beta and TCR gamma delta cells. Immunoprecipitation and Weste rn blotting analyses identified characteristic 115 and 130 kDa reactive com ponents from IEL lysates with mAb S7 and 1B11 respectively, and reactivity to both molecular entities by mAb R2/60, During acute intestinal GVHD induc ed by injecting CB6F(1) athymic nude mice with spleen cells from C57BL/6 en hanced-green fluorescent protein transgenic mice, 80-90% of donor T cells i n the intestine epithelium expressed all CD43 isoforms; however, the level of expression of the 130 kDa CD43 antigen increased significantly and the l evel of the 115 kDa antigen decreased on GVHD donor T cells compared to cel ls at the time of transfer. Using EL4 cells, a similar shift in the express ion of CD43 isoforms occurred experimentally following treatment with neura minidase, suggesting that the type of CD43 isoform expressed on T cells is strongly influenced by conditions which affect membrane charge. The signifi cance of these findings for intestinal immunopathology is discussed.