Th1 Cells That Adoptively Transfer Experimental Hypersensitivity Pneumonitis Are Activated Memory Cells

Abstract.

Cultured murine CD4+ T cell lines from Saccharopolyspora rectivirgula–sensitized donors with cytokine secretion characteristics of Th1 cells can adoptively transfer murine experimental hypersensitivity pneumonitis (EHP), whereas Th2 CD4+ cell lines cannot (Cell Immunol 177:169–175, 1997). To assess the differences between these cell lines that may be related to the ability to transfer EHP, we determined cell surface markers that distinguish naive from activated/memory cells that indicate activation and that mediate endothelial adhesion. Both Th1 and Th2 T cell lines are CD4+, CD11a+, ICAM-1+, and L-selectin negative. Th1 cells are CD49d (α4) and LPAM (α4β7) positive, with 32% and 42% of the apparent membrane site density quantitated as the mean molecules of equivalent soluble fluorochromes (MESF) values of unstimulated spleen cells, respectively. Th2 cells are weakly α4 and α4β7 positive, with 15% and 11% of the MESF of unstimulated spleen cells. Th1 cell lines are CD45Rb negative and CD44+, whereas Th2 cell lines are CD45Rb intermediate and CD44−/low. Th1 cells are CD25 (IL-2 receptor) low and Th2 cells CD25 high. We conclude that Th1 cells capable of transfer are activated/memory T cells, and Th2 cells incapable of transfer lack some characteristics of memory/activated T cells (i.e., increase of CD44 and decrease of CD45Rb). Both Th1 and Th2 cell lines express α4β7 and α4 (Th1 > Th2), suggesting that α₄ integrin may be important in conferring ability to cells to adoptively transfer EHP.