ABSTRACT
@#Objective To develop and verify a method for detecting the activity of neutralizing antibodies in ELISA antibody positive serum of rats immunized with recombinant human interleukin-1 receptor antagonist(rhIL-1Ra). Methods The SD rats were subcutaneously immunized with 3,20 and 100 mg/kg rhIL-1Ra injection respectively,10 rats in each group,half male and half female,twice a day at an interval of at least 4 h between each dose for 13 consecutive weeks. The blood samples were collected from the jugular vein of rats during the administration period and the recovery period. The serum samples were isolated and detected for the antibody titers by ELISA,and the samples positive for rhIL-1Ra antibody were purified by Protein A chromatographic column. Based on,D10G4·1 cells biological activity assay,a method for the detection of neutralizing antibody activity was developed and verified for the specificity,sensitivity and precision. The neutralizing antibody activity of rhIL-1Ra antibody positive serum determined by ELISA was detected by using the developed method.Results With the increase of doses,the serum antibody titers of rats in various dose groups gradually increased,and there were still antibodies in the recovery period,and the titer was still high. Rabbit anti-rhIL-1Ra monoclonal antibody showed obvious neutralizing effect on rIL-1Ra,while rabbit anti-rIFN-2b monoclonal antibody had no dose-effect relationship with rIL-1Ra. The sensitivity of the method was 171. 93 μg/mL;The CVs of precision verification were not more than 20%. The positive antibody sera detected by ELISA all had neutralizing effect on rhIL-1Ra injection,which was consistent with the results detected by ELISA. Conclusion The method developed in this study has good specificity and high sensitivity in the detection of serum neutralizing antibody activity in rats immunized with rhIL-1Ra,which can be used to detect the serum neutralizing antibody activity of animals with rhIL-1Ra repeated administration.