Antigenic variation in rabies virus strains.

Several rabies virus isolates from small wild rodents, one strain isolated from a fox and another from a cat, as well as the CVS strain were compared in cross-protection and virus-neutralization tests. Antigenic variations between the strains and between different batches of individual strains were found. These antigenic differences could not be explained by denaturation caused by UV irradiation or deep-freeze storage, by the presence of "incomplete" particles or by passage in immune organism. An antigenic difference was batch-specific and was only demonstrable on comparison with a relatively large number of strains: it has probably developed during the assembly of antigenic determinants of the virion. There was no correlation between protective and virus-neutralizing activities.