GROWTH-STIMULATING ACTIVITY OF PEPTIDES ON HUMAN HEMATOPOIETIC CELL CULTURES

We have investigated the influence of 21 individual peptides on the growth of RPMI no. 5328 cells in medium RPMI no. 1640 supplemented with 2% dialyzed fetal calf serum. The quantitative data demonstrate that some differences exist between the activity of the dipeptide and the corresponding free amino acid, and also that the cells require pre-formed peptide as such. The media supplemented separately with dl-alanyl-dl-alanine, dl-alanyl-dl-norvaline, dl-alanyl-dl-phenylalanine, dl- or l-leucyl-glycylglycine, l-leucyl-l-tyrosine, tetraglycine, glycyl-dl-phenyl-alanine, glycyl-l-tryptophane and glycyl-dl-valine stimulated cell growth 10% greater than did the controls. The media supplemented with 11 other peptides were slightly active, and some of them occasionally approximated the growth-stimulating effects of these active media, but statistically they were not significantly different from the controls. © 1969.