The influence of spermine, spermidine and various sera on T-lymphocyte and granulocyte colony growth in vitro.

Using T-lymphocyte (T-LC) and granulocyte colony (GC) assays with truly proliferating cells, the dose-response relationships of spermine and spermidine, of fetal calf (FCS), calf (CS), horse (HS) and human AB serum (A B S), and of the polyamines in the presence of selected does of the sera were analyzed. In contrast to earlier observations using [³H] thymidine uptake measurements it was found that the polyamines as well as the sera themselves inhibit T-LC and GC growth in the presence of autologous HS and ABS, respectively. The polyamines also inhibit in the presence of additional HS and ABS, yet most effectively with added FCS and CS. Thus the previously reported species-specificity of the serum-dependent polyamine inhibition has here been shown to be more quantitative than qualitative. These studies stress the significance of assays utilizing truly dividing cells and broad dose-response relationships in order to assess specific biological effects in vitro.