TROPIC DETERMINANT FOR CANINE PARVOVIRUS AND FELINE PANLEUKOPENIA VIRUS FUNCTIONS THROUGH THE CAPSID PROTEIN VP2

Canine parvovirus (CPV) can productively infect canine and feline cell lines whereas feline panleukopenia virus (FPV) is restricted to the l atter. The major determinants of tropism are two amino acids in the se quence shared by the capsid proteins, VP1 and VP2. We have shown that a rodent parvovirus-derived transducing genome, containing the lucifer ase reporter, can be packaged by VP1 and VP2 from separate helper sour ces. Canine A72 cells and feline CFK cells were transduced with recomb inant virions generated using VP1 and VP2 combinations from CPV and FP V. Both VP1 and VP2 were necessary for production of transducing virio ns. Efficient transduction of A72 cells required VP2 of CPV. Therefore , the capsid determinants of tropism for CPV and FPV are in VP2, altho ugh a source of VP1 is also necessary to produce infectious particles. The results extend similar observations on the tropic determinants of different strains of minute virus of mice.