Two antigenic groups of human coronaviruses detected by using enzyme-linked immunosorbent assay

Paired sera from volunteers inoculated with one of the five recently isolated strains of human coronavirus (HCV), AD, GI, HO, PA, and RO, none of which has been grown in tissue culture, or with strain OC38 were tested against coronavirus antigens by enzyme-linked immunosorbent assay. When HCV strains OC43, 229E, or the 229E-related tissue culture-adapted strains PR and TO were used as antigens, it was shown that all strains fell into one of two antigenic groups. The HCV OC43 group was comprised of strains OC43, GI, HO, and RO, and the HCV 229E group contained strains AD and PA as well as the tissue culture-adapted strains PR, TO, and KI. Enzyme-linked immunosorbent assay of the paired sera with the coronavirus mouse hepatitis virus strain 3 as antigen confirmed the relationship of this virus to the HCV OC43 group but not to the HCV 229E group.