Biochemical characterization of an aphthovirus type 0(1) strain campos attenuated for cattle by serial passages in chicken embryos.

The biochemical properties of a virulent and an attenuated strain of foot-and-mouth disease virus (FMDV) Type 0(1) Campos (0(1)C) were compared in order to establish differences that could account for their altered biological functions. The avirulent strain (0(1)C-O/E) was derived from the virulent strain 0(1)C by serial passages in chicken embryos. Analysis of the RNase T1-generated oligonucleotides of the viral RNA through one- and two-dimensional (2D) gel electrophoresis (fingerprints) revealed a few changes in the genome structure of the 0(1)C-O/E strain compared to the wild type strain. In addition there was a significant decrease in the length of the poly(C) rich tract of the 0(1)C-O/E RNA. All virion structural proteins, except VP4, their precursors, and the viral RNA polymerase (p56a) show charge differences. In addition a significant decrease in the apparent molecular weight of polypeptide p100 (primary translational product from the 3' end region of the genome) of the attenuated strain was observed.