Numerous studies have demonstrated that the spike glycoprotein of coronaviruses 
bears major determinants of pathogenesis. To elucidate the antigenic structure 
of the protein, a panel of monoclonal antibodies was studied by competitive 
ELISA, and their reactivities were assayed against fragments of the murine 
coronavirus murine hepatitis virus strain A59 S gene expressed in prokaryotic 
vectors. An immunodominant linear domain was localized within the predicted 
stalk, S2, of the peplomer. It is recognized by several neutralizing antibodies. 
Other domains were also identified near the proteolytic cleavage site, in the 
predicted globular head, S1, and in another part of the stalk. Furthermore, 
competition results suggest that the immunodominant functional domain forms part 
of a complex three-dimensional structure. Surprisingly, some antibodies which 
have no antiviral biological activities were shown to bind the immunodominant 
neutralization domain.