Monkey kidney cells tested in their first culture passage, 24 hours after their isolation from the animal host, required the same 13 amino acids for survival and growth as cell lines serially propagated in culture for years. Under the conditions of the present experiments, arginine, cystine, glutamine, histidine, and tyrosine proved necessary, over and above the 8 amino acids required for nitrogen balance in man.
With the serially propagated lines, glutamic acid substituted for glutamine only at extremely high and non-physiological levels. In the monkey kidney cell cultures, however, glutamic acid and glutamine were interchangeable, mole for mole; and aspartic acid and asparagine were also effective as glutamine substitutes.
Glycine was growth-stimulatory for monkey kidney cells in primary culture, and the cells grown in a glycine-deficient medium usually failed to survive subculture.