RESUMEN
@#Objective To develop and verify a rapid detection method for the biological activity of adalimumab based on U937-NF-κB-Luc cell line. Methods Using U937-NF-κB-Luc cell line as the detection cells,a method for detecting the biological activity of adalimumab was developed based on luciferase luminescence principle. The method was optimized for the concentration of tumor necrosis factor-α(TNF-α)(160 ng/mL as initial concentration,2 times serial dilution,10dilutions),the initial concentration of antibody(2 000 ng/mL,2 times serial dilution,20 dilutions),the dilution multiple of antibody(1. 5,2,3,4 times),the inoculation amount(8 × 103,2 × 104,4 × 104,6 × 104cells/well)and the incubation time(0. 5,1,2,3 h),and verified for the specificity,accuracy,precision and linear range. The relative potency of five batches of adalimumab was detected by using the optimized method and TNF-α neutralization activity method based on L929cells respectively. Results The dose-response curve of adalimumab international standard showed a typical S-type,and the data complied with the four-parameter equation y =(A-D)/[1 +(x/C)B]+ D,R2> 0. 99. The optimum concentration of TNF-α was 5 ng/mL,the initial concentration of antibody was 800 ng/mL,the dilution ratio for adalimumab was 1∶2,the inoculation amount was 2 × 104cells/well,and the induction time was 2 h. Three therapeutic monoclonal antibodies of TNF-α target,such as adalimumab,obtained good dose-response curves,while therapeutic monoclonal antibodies of other non-TNF-α targets did not show this curve. The linear regression equation of the logarithmic value of theoretical potency and the logarithmic value of the corresponding measured potency had a slope of 1. 037,and the relative bias was within the range of ± 12%. The geometric coefficient of variation(GCV)of the relative titer measured value of each sample was less than20%. The theoretical potency ranged from 64% to 156%,showing a good linear relationship with the measured values,and the fitting linear regression equation was y = 1. 037 4 x-0. 023 7,R2= 0. 998 4. There was no significant difference in the relative potency measured results of five batches of adalimumab by the two methods(t = 1. 198,P = 0. 265 1). Conclusion The developed detection method for adalimumab biological activity based on U937-NF-κB-Luc cell line has good specificity,accuracy and precision with short time consumption(3 h),which can be used as a rapid evaluation method for the biological activity of adalimumab.