FL-S and EC-S proteins  Bind to SARS-CoV S1, NTD, RBD, and S2-specific mAbs  MPL + TDM  S.C.  BALB/c mice  Elicit SARS-CoV S-specific Abs (IgG, > 1: 2 × 105), neutralizing (> 1:2.4 × 104) pseudotyped SARS-CoV (Tor2, GD03, and SZ3 strains)  N/A  N/A  He et al., 2006a