Spermine enhances IgM productivity of human-human hybridoma HB4C5 cells and human peripheral blood lymphocytes.

The polyamine spermine was assessed for enhancement of IgM production by human-human hybridoma, HB4C5 cells, under serum-free conditions. IgM production of HB4C5 cells was stimulated approximately 6-fold by the addition of 7.3 mM of spermine. The facilitating effect was observed soon after inoculation. In spite of suppression of cell growth, the IgM production rate was accelerated for at least 5 days without medium change. Moreover, laser confocal microscopic analysis revealed that the IgM content inside HB4C5 cells was increased by spermine treatment. These findings suggest that spermine enhances specific IgM productivity of the hybridoma line. Spermine also facilitated IgM production by human peripheral blood lymphocytes under serum-free conditions. This result implies that spermine enhances immunoglobulin production of not only specific hybridoma lines, but also non-specific immunoglobulin producers. Immunoglobulin production stimulating activity of spermine was accelerated 2-fold by the addition of DNA whith a chain length of about 400-7000 base pairs (bp). However, degraded short-chain DNA fragments (less than 200 bp) did not facilitate the immunoglobulin production stimulating activity of spermine.