CHARACTERIZATION OF 2 DENSITY POPULATIONS OF FELINE CALICIVIRUS PARTICLES

Feline calicivirus (FCV) F9 strain was propagated in Crandall-Reese feline kidney cells. Two density populations of viral particles were observed after equilibrium centrifugation in an isopyknic CsCl gradient. The buoyant density of the heavy particle (P-H) is 1.33 g/ml. The light particle (P-L), a previously undescribed form of feline calicivirus, has a buoyant density of 1.22 g/ml. The P-H and P-L presented a similar morphology by electron microscopy, Western blot showed that both P-H and P-L contained a major polypeptide of the typical FCV capsid protein with a molecular weight of 62,000. Infectivity assay and RNA isolation demonstrated that P-H is the intact infectious virion while P-L is FCV empty capsid. (C) 1994 Academic Press, Inc.