Monoclonal antibodies to a monkeypox virus polypeptide determinant.

Three monkeypox virus (MPV) antibody-secreting murine monoclones were characterized as being of the immunoglobulin G1 isotype, gave a 4+ reaction in the indirect fluorescent-antibody test, gave a positive reaction in the enzyme immunoassay, and did not neutralize MPV. These monoclonal antibodies were determined by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis transblot method to react to a 15,500-molecular-weight MPV polypeptide. This reactivity could not be removed by adsorption to a vaccinia virus-infected cell suspension. The three monoclonal antibodies were specific for MPV when tested against epidemiologically unrelated isolates of cowpox virus, variola virus, vaccinia virus, and MPV.