Fig. 3

IFI27 is involved in cell apoptosis and parasite eradication following early C. parvum infection. A Effect of IFI27 on cell apoptosis in HCT-8 cells. The cells were transfected with pcDNA3.1-IFI27-OE or siRNA-IFI27 for 24 h. Cells were exposed to an equal number of C. parvum sporozoites for 24 h after digestion and staining, and the cell apoptosis ratio was assessed by flow cytometry. Cellular apoptosis was enhanced after transfection with pcDNA3.1-IFI27-OE, but was restrained after transfection with siRNA-IFI27. B, C Effect of IFI27 on the number of parasites in HCT-8 cells. Cells were transfected with pcDNA3.1-IFI27-OE or siRNA-IFI27 for 24 h. Cells were exposed to an equal number of C. parvum sporozoites for 2 h, followed by extensive washing with culture medium. To determine the initial attachment and cellular invasion of C. parvum, the cells were immediately harvested after washing and C. parvum was quantified by real-time PCR. A similar number of parasites was detected in cells transfected with pcDNA3.1-IFI27-OE or siRNA-IFI27 following the initial exposure to C. parvum for 2 h. To determine the parasite burden after the initial cell attachment and invasion, infected HCT-8 cells were cultured for another 22 h after washing, followed by real-time PCR analysis. The C. parvum infection burden was obviously suppressed after transfection with pcDNA3.1-IFI27-OE but was increased after transfection with siRNA-IFI27 in vitro 24 h after the initial parasite exposure. All data represent the combined mean ± SD of three independent experiments with two to three technical replicates per experiment. The data were analyzed with a t-test and compared to cells transfected with an empty vector or nonspecific control siRNA. ^*P < 0.05; ^**P ≤ 0.01