Establishment of a canine cell line: derivation, characterization, and viral spectrum

A cell line, designated A-72, for virus studies was established from a tumor surgically removed from a female, 8-year-old Golden Retriever dog. Following explant culture, the cells were serially passaged 135 times. The A-72 cells maintained a fibroblastic appearance and, at the 123rd passage, had a population doubling time of approximately 27 hours. Karyotypic analysis of the high passage cells showed the modal 2n chromosome number was 92 to 93. Using starch gel electrophoresis for enzyme characterization, the electrophoretic mobilities of enzymes extracted from A-72 cells were identical with those of canine peritoneal fibroblasts and primary canine kidney cells. The A-72 cells were susceptible to infection with infectious canine hepatitis virus, canine adenovirus type II, canine herpesvirus, canine parainfluenza virus, and canine coronavirus, but were not susceptible to canine distemper virus or the minute virus of canines. These cells have been particularly useful for studies of the fastidious canine coronaviruses, as the commonly used primary canine kidney cells exhibit varied susceptibility to these viruses.