Abstract
The nephrosis-inducing infectious bronchitis virus (IBV) was isolated on primary chicken embryo kidney (CEK) cell culture from the kidney lesion of chickens. The cytopathic effect (CPE) was produced only by blind passages of the virus in CEK cell cultures after the adaptation of the virus to embryonating eggs. The maximum infective titer in culture medium appeared in 48 hours after inoculation. The virus was sensitive to ether, chloroform, and sodium deoxycholate, stable at pH 3.0, and was inactivated after heating at 56°C for 45 minutes. No replication was inhibited by 5-bromodeoxyuridine. The virus passed through filters 100mμ or more in average pore diameter, but not through filters 50mμ in such diameter. Its viral particles negatively stained exhibited pleomorphism, were 110mμ in average diameter, and had club-shaped projections on their surfaces. No nucleocapside structure was seen in the virion. Thus, the virus exhibited such properties as typical of coronavirus. It was neutral-ized by the known IBV strains. It is therefore concluded that the virus inducing nephrosis in chickens is the nephrosis-inducing type of IBV in Japan.
