ABSTRACT
Objective To develop and verify an influenza A virus antigen-detecting kit which can detect all the subtypes of influenza A virus. Methods Double-antibodies sandwich enzyme linked immunosorbent assay (ELISA) was utilized for developing the influenza A virus antigen-detecting kit. The sensitivity, specificity, accuracy and stability of the kit were evaluated by the clinical samples. Results The lower detection limit of the kit for the N protein was 7. 63 ng/mL, which was 256 times lower than that of the hemagglutination and 16 times lower than that of immune colloidal gold technique. The kit didn't show any cross-reaction with the influenza B virus, respiratory syncytial virus, respiratory adenovirus, para-influenza virus type Ⅰ and Ⅲ, mycoplasma pneumomiae, avian newcastle disease virus, avian infectious bursal disease virus or avian infectious bronchitis virus. The specificity was 100%. Both the intra batch variaton coefficient (CV) value and inter batch CV value were less than 15%, which met the national standard for ELISA kits. The results proved that the kit could keep stable at 4 ℃ for more than 1 year and at 37 ℃ for more than 7 days. The kit could identify H1N1, H3N2, H5N1 and H9N2 influenza A viruses. The clinical research data of human influenza virus showed the consistency rate between the kit and regular cell culture method was 93. 44% for the positive samples and 99. 31% for the negative samples. The clinical research data of avian influenzavirus showed the consistency rate between the kit and regular cell culture method was 95. 45% for positive samples and 98. 09% for negative samples. Conclusion The influenza A virus antigen-detecting ELISA kit can be used for the epidemiological survey of the infection of human influenza A virus or avian influenza virus with high sensitivity and specificity.