llenge (Du et al., 2009b). Particularly, RBDs from the S proteins of Tor2, GD03, and SZ3, representative strains of SARS-CoV isolated from human 2002–2003, 2003–2004, and palm civet strains, can induce high-titer cross-neutralizing antibodies against pseudotyped SARS-CoV expressing respective S proteins (He et al., 2006c). Di