Vaccination against lethal coronavirus-induced encephalitis with a synthetic decapeptide homologous to a domain in the predicted peplomer stalk.

A surface probability method was used to select a decapeptide homologous to residues 993 to 1002 of the peplomer protein E2 of murine hepatitis virus strain JHM, a neurotropic coronavirus. This sequence of amino acids corresponded to a minor peak on a hydrophilicity plot. Immunization of mice with the chemically synthesized peptide coupled to keyhole limpet hemocyanin elicited high levels of neutralizing antibody and protected against lethal virus challenge. Protection correlated with a critical level of antipeptide antibody, which could be reached after a single inoculation. These results suggest that an appropriate antibody response to a highly restricted, surface-exposed domain of this viral protein is critical in determining the outcome of infection of the central nervous system. This sequence is located in the C-terminal fifth of the E2 peplomers, between two predicted coiled-coil structures.