Lowering the culture temperature has been suggested as a useful tool for improving the production of recombinant proteins in Chinese hamster ovary (CHO) cells. In an effort to improve anti-4-IBB antibody production in recombinant CHO (rCHO) cells, rCHO cells producing anti-4-1BB antibody (LGA31-56) were cultivated at three different temperatures, 30, 33, and 37 degreesC. Lowering the culture temperature led to suppressed cell growth, cell cycle arrest in G(0)/G(1) phase, and improved cell viability for a longer period. However, antibody production and q(Ab) were not increased at low culture temperature. The maximum antibody concentration and q(Ab) at 37 degreesC were 110.6 +/- 2.6 mug mL(-1) and 0.43 +/- 0.03 mug (10(6) cells h)(-1), respectively, whereas those at 30 degreesC were 28.3 +/- 3.8 mug mL(-1) and 0.44 +/- 0.07 (10(6) cells h)(-1), respectively. Northern blot analysis revealed that lowering the culture temperature did not increase the transcription level of heavy and light chains. These results were quite in contrast with the improved production of erythropoietin, which is expressed in the same CHO host and driven by the same CMV promoters, by lowering the temperature. Taken together, the results obtained imply that the beneficial effect of low culture temperature on recombinant protein production in rCHO cells is cell-line-specific.