Analysis of Differentiation Marker Proteins in Helper T Cell Subtypes, Th1 and Th2

抄録

Human helper T cells are divided into T helper (Th) 1 and Th2 cells, which are known to have important roles in cell-mediated and humoral immunity, respectively. In the present study, we attempted to identify cell markers that can distinguish Th1 and Th2 cells using large-scale two-dimensional electrophoresis. Several proteins were found to be specifically and reproducibly expressed in each helper T cell subtype. Three proteins, which have molecular weights of 35000 (spot 1), 40000 (spot 2) and 49000 (spot 3) with pIs of 7.0, 7.0 and 6.3, respectively, were found only in Th1 cells, and the other three proteins, which have molecular weights of 32500 (spot 4), 38000 (spot 5) and 44000 (spot 6) with pIs of 6.5, 6.0 and 5.8, respectively, only in Th2 cells. Spots 1, 3 and 4 were found in both the membrane and the cytosol. Spots 2 and 5 were membrane proteins, while spot 6 was a cytosol protein. The molecular weight of spot 4 resembled that of ST2, which was reported to be a specific cell surface marker of Th2 cells. However, anti-ST2 antibody did not react with spot 4 at all. These results suggest that the proteins found in the present study are novel cell markers of Th1 and Th2 cells.