Investigation of antigenic structure of attenuated and virulent Venezuelan equine encephalomyelitis virus by means of monoclonal antibodies.

A comparative study of the antigenic structure of virulent strains and attenuated vaccine strains of Venezuelan equine encephalomyelitis virus (VEEV) by means of monoclonal antibodies has made it possible to investigate the antigenic structure of the envelope glycoproteins E1 and E2, and to specify their role in the development of antiviral immunity. On the E1 glycoprotein there are five nonoverlapping antigenic sites consisting of eight epitopes that are recognized by monoclonal antibodies; six sites consisting of twenty epitopes were found on the E2 glycoprotein. The monoclonal antibodies against four sites protect the animals from lethal infection with the virulent strain, Trinidad donkey. Out of the thirteen epitopes identified as being responsible for antiviral immunity, three are changes in the TC-83 strain, and six belong to two sites in the strain 230. The results obtained indicate the necessity for further improvement of the available vaccine preparations against this dangerous infectious disease.