Biochemical Changes in Virus-infected and Regenerating House Liver

Abstract

THE biochemical changes accompanying the multiplication of an animal virus within its host cell are still largely unknown. Alterations in the levels of activity of a variety of enzymes in mouse brain infected with virus have been reported by Bauer¹. In this system the number of infected cells is not known and the variety of cell types and possibility of compensatory changes in other neurones make interpretation difficult. Tissue cultures infected with poliovirus show marked changes in various enzyme activities², but here the considerable variation in physiological state of the culture produced by small experimental variations must be borne in mind when interpreting results. The effects of a virus on the cells of its natural mammalian host can be studied conveniently in the livers of mice infected with large (10⁹–10¹⁰ LD50) intravenous inocula of ectromelia virus³. Simultaneous infection of almost all hepatic parenchymal cells takes place, there is no cellular infiltration, and up to 30 hr. after infection there is little or no necrosis. Mouse livers so infected show a progressive increase in size without cell division. The comparison between normal growth in regeneration and that induced by infection, of either normal or regenerating liver, is of some interest. In liver regenerating after partial hepatectomy increase in cell size is followed by cell division, but in regenerating liver infected with ectromelia mitosis is inhibited⁴. Other evidence for nuclear changes is decreased synthesis⁵ of coenzyme I and decreased adenosine deaminase activity in both infected and regenerating livers.