Insect cells respiratory activity in bioreactor.

Specific respiration rate ( [Formula: see text]) is a key parameter to understand cell metabolism and physiological state, providing useful information for process supervision and control. In this work, we cultivated different insect cells in a very controlled environment, being able to measure [Formula: see text]. Spodoptera frugiperda (Sf9) cells have been used through virus infection as host for foreign protein expression and bioinsecticide production. Transfected Drosophila melanogaster (S2) cells can be used to produce different proteins. The objective of this work is to investigate respiratory activity and oxygen transfer during the growth of different insect cells lines as Spodoptera frugiperda (Sf9), Drosophila melanogaster (S2) wild and transfected for the expression of GPV and EGFP. All experiments were performed in a well-controlled 1-L bioreactor, with SF900II serum free medium. Spodoptera frugiperda (Sf9) cells reached 10.7 x 10(6) cells/mL and maximum specific respiration rate ([Formula: see text]) of 7.3 x 10(-17) molO(2)/cell s. Drosophila melanogaster (S2) cells achieved 51.2 x 10(6) cells/mL and [Formula: see text] of 3.1 x 10(-18) molO(2)/cell s. S2AcGPV (expressing with rabies virus glycoprotein) reached 24.9 x 10(6) cells/mL and [Formula: see text] of 1.7 x 10(-17) molO(2)/cell s, while S2MtEGFP (expressing green fluorescent protein) achieved 15.5 x 10(6) cells/mL and [Formula: see text] = 1.9 x 10(-17) molO(2)/cell s. Relating to the Sf9, S2 cells reached higher maximum cell concentrations and lower specific respiration rate, which can be explained by its smaller size. These results presented useful information for scale-up and process control of insect cells.

Teste de tumorigenicidade em células vero / Tumorigenicity testing of vero cells

Six-week-old athymic nude mices were used to test the capacity of Vero cell line to induce the tumor formation. KB cell line, obtained from human oral epidermoid carcinoma, was used as a positive test control. KB cell has proved to be a good positive control for tumorigenicity tests, since all the animals inoculated with this cell developed tumorous mass. These tumors started appearing in mice between 4th and 8 th days after inocullation, gradually progressed until reaching the maximal axes of 18 to 21 mm in the end of the test. None of the animals inoculated with Vero cells developed tumors in the test, demonstrating that way, that the Vero line at passages 145, 149 and 151 is not carcinogenic