[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 (Mr ) 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.