Comparison of the proteins of bovine and ovine parainfluenza-3 viruses.

Bovine and ovine parainfluenza-3 (PI-3) virus proteins were compared using polyclonal and monoclonal antibodies in western blot analysis. Eight proteins ranging in molecular weight (MW) from 14 kD to 190 kD of bovine PI-3 virus were demonstrated in this study. The 14 kD MW protein has not been previously described for bovine PI-3 virus. Western blot analysis of ovine PI-3 virus using homologous serum produced 7 bands ranging in MW from 12 kD to 190 kD described for the first time in this paper. Using rabbit polyclonal antibodies against bovine PI-3 virus a 160 kD MW protein was demonstrated in the bovine virus strain, but not in the ovine PI-3 virus strain and a protein band appeared in the ovine PI-3 virus strain at a MW of 23 kD but not in the bovine PI-3 virus strain. Using lamb polyclonal antibodies to ovine PI-3 virus against the homologous virus, 6 protein bands were visible with a MW range from 12 kD to 175 kD; for bovine PI-3 virus 5 protein bands were resolved. There was a difference observed in the mobility of the 120 kD MW protein for ovine PI-3 viral protein but not for the bovine PI-3 viral protein. Differences were observed for ovine PI-3 viral protein at the level of the 12 kD MW protein whereas the lowest detected band for the bovine PI-3 viral protein was 37 kD MW. The monoclonal antibodies prepared against bovine PI-3 virus produced 3 distinct protein bands. Two bands of MW 110 and 140 kD were identical for both viruses whereas the third band for bovine PI-3 virus was 37 kD MW and that for ovine PI-3 virus was 55 kD MW.