David T. Karzon

Cultivation of Enteroviruses in Hamster Kidney Tissue Culture

Summary Susceptibility of hamster kidney tissue culture to enteroviruses was studied. A cytopathogenic effect was obtained with the prototype Coxsackie viruses (A9, B1–B5) and prototype ECHO virus types 9 and 10. Variability of infectivity was shown for ECHO 9 isolates, only 2 of 27 positive. Other ECHO serotypes and polioviruses were negative. Strains of herpes simplex, vaccinia, Newcastle disease virus and influenza (Asian), also produced a cytopathogenic effect in hamster kidneys. Use of hamster kidney tissue cultures as a selective system in identification of agents from cases of aseptic meningitis was reported.

Effect of pH on Cytopathogenicity of Orphan Viruses.

Summary 1. The cytopathogenic titer of certain orphan viruses in monkey kidney tissue culture was depressed or delayed when grown in the presence of a medium which developed an acid pH. This phenomenon has been termed the apH effect. 2. Sensitivity to the “pH effect” appeared to be strain characteristic. Differences occurred among serotypes as well as within serotypes of the orphan viruses. One Coxsackie group B virus tested also demonstrated the “pH effect.” Two poliovirus types tested were minimally affected by pH variation. 3. Neutralization of tissue culture acidity with an excess of NaHCOs, or prevention of acid formation by omission of glucose restored optimal viral cy-topathogenicity. 4. The “pH effect” tended to be less evident with rapidly cytopathogenic agents or in the presence of large inocula. 5. Rate of primary isolation of orphan virus from stool suspensions was substantially decreased when acid producing tissue culture medium was used.