Etiologic Relationship of Marmoset-Propagated CR326 Hepatitis A Virus to Hepatitis in Man

Summary Studies were conducted to define the etiologic relationship of CR326 hepatitis virus recovered in marmosets to hepatitis A in man. CR326 virus exhibited physical-chemical properties considered characteristic of human hepatitis A virus, viz, small size and heat, ether and acid stability. A serum neutralization test carried out with CR326 virus in S. mystax marmosets is described and the factors influencing the results are given. Tests of paired sera from 8 cases of hepatitis A and 2 cases of hepatitis B were carried out including coded paired sera from 3 human subjects given MS-1 strain hepatitis A and 1 given MS-2 strain hepatitis B virus of human source. All subjects with hepatitis A developed antibody that neutralized CR326 virus; there was no such antibody response in persons with hepatitis B. All of 3 samples of human immune globulin neutralized the CR326 agent. Neutralization was highly effective since marmosets given the neutralized virus remained susceptible to reinfection with the agent; by contrast recovered animals that had been given non-neutralized virus were immune to reinfection. All evidences to establish the relationship of CR326 virus to human hepatitis A are summarized.