Attachment and internalization of feline infectious peritonitis virus in feline blood monocytes and Crandell feline kidney cells.

Van Hamme, Evelien; Dewerchin, Hannah L; Cornelissen, Els; Nauwynck, Hans J

In this study, kinetics of attachment and internalization of feline infectious peritonitis virus (FIPV) serotype I strain Black and serotype II strain 79-1146 were determined in feline monocytes from two cats and in Crandell feline kidney (CrFK) cells. Attached FIPV I (Black) particles were observed on almost all monocytes. Within 1 h, 17 particles were bound per cell and, within 1 min, 89 % of the bound particles were internalized. For FIPV II (79-1146), attachment was observed on 66 and 95 % of all monocytes from the two cats. After 1 h, respectively five and 20 particles were bound per cell (all cells considered). Within 1 min, 60 % of the bound particles were internalized. Internalization in monocytes was efficient and proceeded via endocytosis. In CrFK cells, attachment and internalization were less efficient, especially for FIPV I (Black), so this cell line is not suitable for studying FIPV entry.