Application of a serum-free medium in the growth and differentiation of human peripheral blood lymphocytes.

To eliminate variability due to nonspecific stimulation or inhibition by different lots of fetal bovine serum, the activation of human peripheral blood mononuclear cells in a modification of Iscove's medium (medium C-IMDM) was compared with the routinely used Roswell Park Memorial Institute (RPMI)-1640 medium containing 15% fetal bovine serum. Stimulation of peripheral blood mononuclear cells was enhanced and occurred at lower mitogen concentrations in C-IMDM compared with cells grown in RPMI-1640 supplemented with fetal bovine serum. Maximum incorporation of [3H]thymidine following stimulation by concanavalin A, phytohemagglutinin, and pokeweed mitogen was more than twice the peak values obtained in RPMI-1640 supplemented with fetal bovine serum. Concentrations of concanavalin A and phytohemagglutinin required for maximum stimulation were 0.5 and 15 micrograms/ml, and 0.3 and 1.0 micrograms/ml . 5 X 10(5) cells in C-IMDM and RPMI-1640, respectively. Cells grown in C-IMDM responded to lower concentrations of pokeweed mitogen and optimal growth in the serum-free medium required 0.4 micrograms/ml . 5 X 10(5) cells. The stimulation of immunoglobulin-producing cells in C-IMDM was enhanced and occurred at lower concentrations of pokeweed mitogen. Less variability of growth (i.e., incorporation of [3H]thymidine) and immunoglobulin synthesis occurred in peripheral blood mononuclear cells cultured in different preparations of C-IMDM than that reported for cells cultured in RPMI-1640 supplemented with different lots or batches of fetal bovine serum. These data suggest that C-IMDM may be an alternative to media supplemented with fetal bovine serum.