ELISA--a simple test for detecting and differentiating antibodies to closely related orthopoxviruses.

In this paper, the results are reported of experiments to investigate the optimum conditions for determining, and differentiating between, the antibodies against closely related poxviruses using the ELISA technique. This assay was found to be considerably more sensitive than the virus neutralization, haemagglutination inhibition, passive haemagglutination, and indirect fluorescent antibody tests for detecting antibodies, but has not yet been compared with radioimmunoassay. The use of ELISA made it possible to differentiate between antibodies to vaccinia, whitepox, and monkeypox viruses.