LATENT VIRAL INFECTION OF CELLS IN TISSUE CULTURE : VII. ROLE OF WATER-SOLUBLE VITAMINS IN PSITTACOSIS VIRUS PROPAGATION IN L CELLS

A study of the metabolic requirements for the growth of psittacosis virus in L cells has been extended to the water-soluble vitamins. In a system in which a balanced salt solution was used to deplete the cells of their vitamin constituents, only thiamine was essential for psittacosis virus production. Extended depletion of cells with media deficient in specific vitamins demonstrated that pantothenate, niacin (niacinamide), pyridoxine (pyridoxal), and choline, in addition to thiamine, were essential for maximal growth of psittacosis virus. No requirement for biotin, inositol, folic acid, or riboflavin was demonstrated, although the possibility of incomplete vitamin depletion of the cells has not been eliminated. In most cases in which a specific vitamin requirement was shown the decreased yield of virus was correlated with a delay in the cytopathic effects produced in the cell cultures by psittacosis virus.