Objective To detect the expression level of ICOS on Th9 cells in mice infected with Schistosoma japonicum,and investigate the relation between ICOS signaling and Th9 cell polarization. Methods Twenty.five mice with S. japonicum infec.tion were used as models. IL.9+cells in CD4+ T cells and ICOS+ cells in Th9 cells of the mice were detected by flow cytometry 0,4,7,9 weeks and 12 weeks after the infection. Results Compared with that 0 week after the infection,the proportion of Th9 cells in CD4+ T cells of the...