Bone marrow stromal cell antigen 2 (BST2)
As the first defense line against pathogenic microorganism invasion, natural immune response plays a vital antiviral role in the early stage of virus infection. The critical role of interferon (IFN) in the process of virus infection and proliferation has long been recognized. As a IFN-induced common natural immune limiting factor (Sauter D, 2014; K. S et al., 2003), BST2 can suppresses viral production through affecting the release of viruses from infected cells (V. D. N et al., 2008). By analyzing the distribution of BST2 in tissues, Kong et al. found that in spite of its expression in almost all tissues and organs, BST2 exhibited high level in immune tissues and organs, large intestine, small intestine and lungs, hinting a key role of BST2 in early natural immune response. Indeed, the BST2 overexpressing Vero cells had much less virus content than that of the control cells, similarly, the viral titer in the cell supernatant was also pronouncedly reduced. On the contrary, PEDV proliferation was remarkably enhanced in Vero cells upon downregulating BST2 gene level, suggesting that BST2 protein could restrain PEDV proliferation in Vero cells. Furthermore, this function of BST2 might be achieved by binding and degrading the N protein of PEDV (K. N et al., 2019).
Other factors in the host cells affecting PEDV infection