Fig. 3.

FcεRI is involved in PRRSV-antibody immune complex attachment and internalization. A 3D4/21 cells were transfected with pcDNA3.1-FcεRI or pcDNA3.1 (1 μg) for 24 h, respectively, and then the transfected cells were treated with PRRSV, PRRSV + IgG⁻, PRRSV + IgG⁺ (MOI = 1) or PBS (Mock). Twenty-four hours after PRRSV infection, cells were harvested. PRRSV RNA load levels were analyzed by RT-qPCR. B 3D4/21 cells were treated with rabbit anti-FcεRI antibody against FcεRI (to block FcεRI) in an incubator at 37 °C for 1 h, and then treated with PRRSV, PRRSV + IgG⁻, PRRSV + IgG⁺ (MOI = 1) or PBS (Mock). Twenty-four hours after PRRSV infection, cells were harvested. PRRSV RNA load levels were analyzed by RT-qPCR. C Western blotting analysis of FcεRI protein in HEK293-T cells. D HEK 293T cells were transfected with pcDNA3.1-FcεRI or pcDNA3.1 (1 μg) for 24 h, respectively, and then the transfected cells were treated with PRRSV, PRRSV + IgG⁻, PRRSV + IgG⁺ (MOI = 1) or PBS (Mock). Twenty-four hours after PRRSV infection, cells were harvested. PRRSV RNA load levels were analyzed by RT-qPCR. Bars indicate the 2^−ΔΔCT of FcεRI mRNA copies in infected cells or mock-infected cells; error bars indicate SD from two independent experiments. *P < 0.05 according to t test.