Behaviour of rubella virus in human diploid cell strains. II. Studies of infected cells.

Abstract

Rubella virus infection of human diploid cells did not result in an ordinary cytopathic effect, but several kinds of human diploid cell strains (HDCS) responded to infection by ceasing to multiply. Inhibition occurred quickly (most lung strains), or after many weeks (skin and pharyngeal mucosa strains). HDCS could be classified according to their response. The response of lung cell strains was strictly related to thein vitro age of the strains at the time of infection. Older strains stopped multiplying several times more quickly than younger ones. The relationship was not found for HDCS of other organ and tissue origins. Pericardial cell strains possessed large amounts of acid phosphatase-containing granules in a small proportion of the cells. During chronic rubella infection, histochemical activity of the enzyme decreased. The chromosomes of chronically infected skin, lung, pharyngeal mucosa and pericardial strains, infected up to 17 cell generations earlier, showed a mild but definite increase in achromatic gaps and breaks. No evidence of cell transformation or induction of neoplastic changes was found in HDCS which had been actively dividing for up to 27 weeks while infected with rubella.