Printed in Great Britain Biochemical and Antigenic Comparisons of the Envelope Glycoproteins of Venezuelan Equine Encephalomyelitis Virus Strains

Pulse-chase xperiments after synchronous initiation of translation indicate that the larger Venezuelan equine encephalomyelitis (VEE) virus membrane glycoprotein, E2, is derived by proteolytic leavage of the precursor, PE2. The structural proteins of VEE virus strains representing each of the antigenic subtypes and varieties have been compared by discontinuous SDS-polyacrylamide g l electrophoresis. Nucleocapsid proteins of all isolates were similar in size (mol. wt. 35 to 36 × lO3). The mol. wt. of E ~ varied from 48 to 51 × IO a and the mol. wt. of E ~ glycoproteins ranged from 53 to 59 × Ioa. Pixuna virus contained a third envelope glycoprotein of 59 × IOa mol. wt. in addition to the two major glycoproteins of mol. wt. 53 × lO3 and 48 × Io 3 respectively. The isoelectric points (pI) of Ex and Ez for all VEE strains studied were approx. 7 and 9 respectively. Both glycoproteins of TC-83 virus induced precipitating antibodies which reacted only with the homologous purified E1 and E2 glycoproteins. Antibodies to E3 protein of each virus neutralized virus infectivity and inhibited the agglutination of goose rythrocytes by virions. Haemagglutination-inhibition tests using antisera to E~. glycoproteins of prototype viruses, representing each of the antigenic sub-types and varieties, differentiated the viruses into subtypes I, II, lII and IV with subtype I divided into variants tAB, I C, i D and I E