Effect of L-carnitine and acylcarnitine derivatives on the proliferation and monoclonal antibody production of mouse hybridoma cells in culture.

The effect of L-carnitine (Cn) on cell growth metabolism and antibody production rates was investigated using the murine hybridoma cell line, Mark3, in batch and fed harvest cultures. Two acylcarnitine derivatives were also tested: palmitoyl L-Cn and acetyl-DL-Cn. The addition of 20 microM L-Cn to cultures of Mark3 hybridoma cells that had been adapted to L-Cn significantly stimulated monoclonal antibody (mAb) production without affecting cell growth. In contrast, mAb secretion slightly decreased when L-Cn was added to culture of cells that had not been adapted to L-Cn. Palmitoyl L-Cn also stimulated mAb production by adapted cells, whereas the acetyl-DL-Cn, reduced mAb secretion. The presence of L-Cn in the medium did not affect glucose consumption or lactate production, but the metabolism of some amino acids was altered. The medium concentrations of valine, leucine, isoleucine and lysine were enhanced from 22% to 41% according to amino acids, whereas those of alanine, glycine and proline decreased. The mechanism by which L-carnitine affects mAb production and the metabolism of some amino acids is unknown. This effect is likely to be indirect, since there was no net entry of L-[3H]carnitine into the cells.