Objective:To realize prokaryotic expression, purification and identification of 2019-novel Coronavirus (2019-nCoV) nucleocapsid protein (NP), and apply it to the serological diagnosis.Methods:The synthetic 2019-nCoV NP gene was cloned into the prokaryotic expression vector pET28a to construct expression plasmid, and then purified by Ni-chelating affinity. SDS-polyacrylamide gel electrophoresis (SDS-PAGE), indirect enzyme-linked immunosorbent assay (ELISA), Western blot (WB), and immunochromatography were used to test the purified protein. Indirect ELISA reaction conditions were optimized for serum antibody detection.Results:The relative molecular mass of recombinant NP was about 50×10 3 after SDS-PAGE electrophoresis, which was consistent with the expectation. Indirect ELISA and WB results showed that it could specifically bind to the serum of patients infected with 2019-nCoV. The detection limit of NP was 0.2 ng/ml by immunochromatography. The sera from 32 patients infected with 2019-nCoV and the control sera were detected by indirect ELISA, and the results showed that they were clearly clustered. Conclusions:Prokaryotic expression of 2019-nCoV NP has good immunogenicity and can be used for the development of serological diagnostic reagents.

Purpose: This study aims to evaluate the efficacy and safety of a new combination treatment of vinorelbine and pyrotinib in human epidermal growth factor receptor 2 (HER2)–positive metastatic breast cancer (MBC) and provide higher level evidence for clinical practice. Materials and Methods: This was a prospective, single-arm, phase 2 trial conducted at three institutions in China. Patients with HER2-positive MBC, who had previously been treated with trastuzumab plus a taxane or trastuzumab plus pertuzumab combined with a chemotherapeutic agent, were enrolled between March 2020 and December 2021. All patients received pyrotinib 400 mg orally once daily plus vinorelbine 25 mg/m2 intravenously or 60-80 mg/m2 orally on day 1 and day 8 of 21-day cycle. The primary endpoint was progression-free survival (PFS), and the secondary endpoints included the objective response rate (ORR), disease control rate (DCR), overall survival, and safety. Results: A total of 39 patients were enrolled. All patients had been pretreated with trastuzumab and 23.1% (n=9) of them had accepted trastuzumab plus pertuzumab. The median follow-up time was 16.3 months (95% confidence interval [CI], 5.3 to 27.2), and the median PFS was 6.4 months (95% CI, 4.0 to 8.8). The ORR was 43.6% (95% CI, 27.8% to 60.4%) and the DCR was 84.6% (95% CI, 69.5% to 94.1%). The median PFS of patients with versus without prior pertuzumab treatment was 4.6 and 8.3 months (p=0.017). The most common grade 3/4 adverse events were diarrhea (28.2%), neutrophil count decreased (15.4%), white blood cell count decreased (7.7%), vomiting (5.1%), and anemia (2.6%). Conclusion Pyrotinib plus vinorelbine showed promising efficacy and tolerable toxicity as second-line treatment in patients with HER2-positive MBC.