Improved protein-A chromatography for monoclonal antibody purification / 生物工程学报

Therapeutic monoclonal antibodies become the major product class within the biopharmaceutical market. Protein A as the first capture step is still dominant in current platforms for purification of monoclonal antibodies. In this study, we developed a new antibody harvest process that incorporates acidic treatment of cell harvest, demonstrating high process yield, improved clearance of host cell associated contaminants, like non-histone host cell protein, histone, DNA and heteroaggregates. Host protein contamination was reduced about 10-fold compared to protein A loaded with harvest clarified by centrifugation and microfiltration. Turbidity increase of eluted IgG upon pH neutralization was nearly eliminated. Residual levels of impurities in the protein A eluate were achieved that potentially meet requirements of drug substance and thus alleviate the burden for further impurities removal in subsequent chromatography steps. The mechanism of host cell associated contaminants removal during acidic treatment was also explored. After a polishing step by Capto adhere, host cell protein was reduced to less than 5 ppm, DNA less than 1 ppb, histone to undetectable level, heteroaggregates less than 0.01% with total IgG recovery around 87%. This efficient process can be easily integrated into current IgG purification platforms, and may overcome downstream processing challenges.

Adriamycin enhances the sonodynamic effect of chlorin e6 against the proliferation of human breast cancer MDA-MB-231 cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of adriamycin (ADM) in enhancing the sonodynamic effect of chlorin e6 against the proliferation of human breast cancer MDA-MB-231 cells in vitro.</p><p><b>METHODS</b>MDA-MB-231 cells were treated with ultrasound/Chlorin e6 alone or in combination with ADM, and the changes in the cell proliferation was determined by MTT assay.</p><p><b>RESULTS</b>Ultrasound (1.0 MHz) at the power intensity of 0.5-2.0 W/cm2 inhibited the proliferation of MDA-MB-231 cells in an intensity-dependent manner, and chlorin-e6 (0.05-1.6 mg/ml) and ADM (0.1-0.4 g/ml) alone both inhibited the proliferation of MDA-MB-231 cells dose-dependently. Compared with ultrasound (0.5 W/cm2, 1.0 MHz, 60 s) or chlorin-e6 (0.05-0.2 mg/ml) alone, a combined treatment with ultrasound and chlorin e6 significantly enhanced the inhibitory effect on the proliferation of MDA-MB-231 cells (P<0.05). ADM significantly enhanced the sonodynamic effect of chlorin e6 (0.1 mg/ml) against the cell proliferation of MDA-MB-231 cells (P<0.05), and the effect was schedule-dependent, which was greater when ADM was added after the sonodynamic treatment (P<0.05).</p><p><b>CONCLUSION</b>ADM can enhance the sonodynamic effect of chlorin e6 against the proliferation of MDA-MB-231 cells in vitro.</p>