RESUMO
@#Objective To prepare rabbit polyclonal antibodies against pertussis toxin(PT) and develop a double antibody sandwich ELISA for quantitative determination of PT antigen,identify and apply the method.Methods The rabbit polyclonal antibody against PT was prepared by immunizing Chinchilla rabbit with PT using traditional method.The reaction conditions of ELISA system were optimized,the double antibody sandwich ELISA method for quantitative determi-nation of PT was developed,and the specificity,linearity,accuracy,precision and sensitivity were verified.The developed method was used to detect PT antigen content in fimbriae proteins(FIM) stock solution of samples during detoxification and other purification process of pertussis antigen.Results The working condition of double antibody sandwich ELISA for detection of PT antigen content was the coating concentration of PT rabbit polyclonal antibody of 1 μg/mL,and the enzyme-labeled antibody dilution of 1:8 000.This detection system showed specific reaction with PT purified protein,but had no cross reaction with filamentous hemagglutinin,diphtheria toxoid and tetanus toxoid;the linear detection range of the developed double antibody sandwich ELISA was within 25—400 ng/mL;the recovery rates of PT at high,moderate and low concentrations were 103.27%,91.48% and 103.52%,respectively;both the intra-and inter-coefficients of variation(CVs)were less than 10%;the sensitivity of the method was 20.719 ng/mL,and the detection limit was 41.438 ng/mL.Thirty-five batches of samples were detected under five different detoxification process conditions and at different sampling time points,and the changes of antigen content were all consistent with the trend of detoxification reaction.Conclusion The PT rabbit polyclonal antibody was successfully prepared,and a double antibody sandwich ELISA with high precision and accuracy was developed for the quantitative determination of PT antigen content,which can be used for the antigen content detection of chemically detoxified samples in the production process of component DPT vaccines