[Detection of serum anti-NS2 antibody and recombinant hepatitis C virus nonstructural protein 2 (NS2): its development and evaluation].

Objective To express the recombinant HCV NS2, establish and evaluate the detection method of serum anti-ns2 antibody based on chemiluminescence. Methods Using the NS2 sequence plasmid of HCV 1b genotype (PUC-NS2) as the template, a recombinant plasmid containing the whole NS2 sequence (pGEX-KG-NS2) was constructed. Prokaryotic expression of NS2 protein was induced. The purified NS2 fusion protein was coated on the microplate, and the anti-NS2 antibody detection kit was prepared based on chemiluminescence, and the methodological index was evaluated. Results NS2 fusion protein with relative molecular weight (M) of about 51 000 was successfully induced and expressed, and a serum anti-NS2 antibody detection kit was synthesized. Methodological evaluation of kit: Precision test showed favorable results (intra batch coefficient of variation [CV] was 4.60%~9.17%, inter batch CV was 6.62%~10.09%). The relative luminous intensity ratio (RLIR) of the blank limit and the detection limit were 1.57 and 4.80 (r=0.9870), respectively, and the analytical measurement range (AMR) was 1.63~44.50 RLIR. Accuracy experiments: The average recovery was 99.4%. The positive serum samples such as rheumatoid factor had no cross reaction to this test, and the kit was stable within 15 months. The positive rate of anti-NS2 antibody in serum of 45 HCV infected patients was 20% (9/45). Conclusion The prokaryotic expression of HCV NS2 fusion protein is successfully obtained, and the anti-NS2 antibody detection kit in serum is developed.