Early interaction of feline calicivirus with cells in culture

The kinetics and biochemical properties of feline calicivirus (FCV) attachment to Crandell-Reese feline kidney cells were determined. Maximum binding was observed at pH 6.5. Cells in suspension at 4 degrees C bound virus more efficiently than cells in monolayers at 4 degrees C or 37 degrees C. High initial binding rate was observed in monolayers or cells in suspension and proceeded to a maximum at 90 min, although half maximal binding was observed as early as 15 min. Binding was specific and competitively blocked by serotypically homologous or heterologous FCV as well as by San Miguel sea lion virus. Treatment of cells with proteases increased FCV binding, whereas phospholipase had no effect on virus attachment. Conversely, cells treated with neuraminidase followed by O-glycanase treatment showed a decreased binding ability. Cells of feline origin bound FCV very efficiently, and non-permissive cells showed a poor binding ability. Following transfection of viral RNA, infectious virus could be recovered from all non-permissive cells, except from Madin-Darby canine kidney cells. These results suggest that FCV binds to a receptor in which carbohydrates may be an important component and that FCV replication in non-permissive cells is primarily restricted by the absence of appropriate receptors on the cell surface.