Properties of a virus isolated from patients with MS-1 infectious hepatitis.

A virus was isolated from acute-phase plasma of a patient (K), who developed hepatitis four weeks after receiving serum containing the agent of MS-1 infectious hepatitis. The isolated agent produced a cytopathic effect in a cloned line of Detroit 6 (D6) cells. Infected cultures yielded viral particles with a diameter of 18-20 nm. The virus was resistant to treatment with ether. The acute-phase plasma, but not the preinfection serum, of patient K also produced interference against echovirus type 11 in primary cultures of human or simian renal cells. In some cases, virus passed in D6 cells elicited an interfering factor. Oral passage of the virus-containing plasma produced hepatitis in five volunteers, and a virus was isolated in D6 cells from acute-phase plasmas of four of these patients. An interfering factor was detected in the acute-phase plasmas of three of the latter patients, but not in the plasmas taken before infection. Of the eight volunteers who developed hepatitis, only patient K developed neutralizing antibodies to the cytopathic and interfering agent. Neither the original inoculum containing MS-1 nor the isolated virus contained Australia antigen.