Mouse fibroblasts (L cells) fail to support the growth of psittacosis virus (6BC strain) if they are maintained on a medium containing only inorganic salts and glucose for 2 days prior to infection. Virus propagation can be stimulated by the addition of a synthetic medium containing amino acids, water-soluble vitamins, glutamine, glucose, and inorganic salts. By omitting single amino acids from the complete synthetic medium, tyrosine, threonine, methionine, isoleucine, phenylalanine, tryptophan, leucine, valine, and cysteine or cystine were found to be essential for stimulation, while lysine, arginine, histidine, hydroxyproline, proline, glutamic acid, aspartic acid, serine, alanine, and glycine were not essential. The cells on deficient media showed varying degrees of degenerative changes, but there was little correlation between ability to support psittacosis virus growth and morphologic condition of the cells. Glucose is also an essential component of the medium for viral growth, but the absence of glutamine had no effect on stimulation of virus propagation. L cell cultures maintained on media deficient in phenylalanine or tryptophan for 2 days before infection were also found to be incapable of supporting virus growth. The implications of this study in latent viral infections are discussed.

Amino Acids↗

PubMed1958

Gastro-enterology.

Explore the source record for details and available documents.

Humans↗

PubMed1957

Latent viral infection of cells in tissue culture. IV. Latent infection of L cells with psittacosis virus.

By maintaining L cells in a balanced salt solution of inorganic salts and glucose (BSS) for 2 days or more, they are rendered incapable of supporting the growth of psittacosis virus (6BC), though it infects such cells and is present intracellularly for as long as 3 days in a non-infectious phase. The addition of an enriched medium to such a culture of cells at any time up to 4 days after infection results in the appearance of infectious virus within these cells, which multiplies and is released from the cells, providing the entire period of exposure of such cells to the BSS does not exceed 6 days, following which the cells die. A latent infection with psittacosis virus in a non-infectious phase has been established in a pure line of cells which possess properties of malignancy.

Chlamydophila psittaci↗

PubMed1957