Rabies virus strains: A comparison study by polypeptide analysis of vaccine strains with different pathogenic pattern

The five constitutent polypeptides of the rabies vaccine strains ERA, HEP, CVS, and PM (serotype 1) and Mokola (serotype 3) have been examined by tryptic peptide analysis. A comparison of the tryptic peptides of the N proteins of Mokola and the four serotype 1 strains revealed a general similarity. In contrast only few tryptic peptides of the G or M proteins were shared between different serotypes. While the tryptic peptide patterns of the corresponding M1, M2, N, and L proteins of the four vaccine strains show a great similarity the analysis of the tryptic peptides revealed characteristic differences in the G proteins. An overall comparison of the tryptic peptide patterns of the structural proteins of the four vaccine strains indicates that CVS and PM are more closely related to each other than to ERA or HEP. Characteristic qualitative and quantitative differences between the four vaccine strains were also demonstrated by their polypeptide patterns in SDS-PAGE. HEP, CVS, and PM each have two M1 proteins which differ in their phosphate content. ERA, on the other hand, contains only a single M1 protein which is characterized by a very low phosphate content. In contrast to ERA and HEP, CVS and PM each contain two glycoproteins, which have identical leucine-containing tryptic peptides but differ in the carbohydrate content. Whereas the pathogenic strains CVS and PM possess 150 and 104 L protein molecules per virion, 17 and 37 L protein molecules per virion were found to be present in the less pathogenic strains ERA and HEP.