The S/C values comparing with HRP-ch2C5, Nluc-ch2C5 (left); LOD of Nluc-MBS-ch2C5 (right). rapidly. However, due to the low sensitivity, it can only be used as an auxiliary diagnosis method for virus infection. Improving sensitivity is crucial for developing more accurate viral antigen tests. Nano luciferase (Nluc) is a sensitive reporter that has not been used in virus detection. Results In this study, we produced an intracellularly Nluc labeled detection antibody (Nluc-ch2C5) and evaluated its ability to improve the detection sensitivity of respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens. Compared with the traditional horse-radish peroxidase (HRP) labeled antibody (HRP-ch2C5), Nluc-ch2C5 was 41 times more sensitive for inactivated SARS-CoV-2 virus by sandwich chemiluminescence ELISA. Then we applied Nluc-ch2C5 to establish an automatic magnet chemiluminescence immune assay (AMCA) for the SARS-CoV-2 viral spike protein, the limit of detection VCP-Eribulin was 68 pfu/reaction. The clinical sensitivity and specificity reached 75% (24/32) and 100% (48/48) using 32 PCR-positive and 48 PCR-negative swab samples for clinical Mouse monoclonal to IKBKE evaluation, which is more sensitive than the commercial ELSA kit and colloid gold strip kit. Conclusions Here, monoclonal antibody ch2C5 served as a model antibody and the SARS-CoV-2 served as a model pathogen. The Nluc labeled detecting antibody (Nluc-ch2C5) significantly improved the detection sensitivity of SARS-CoV-2 antigen. This labeling principle applies to other viral infections, so this labeling and test format could be expected to play an important role in detecting other virus antigens. Supplementary Information The online version contains supplementary material available at 10.1186/s12985-022-01855-6. Keywords: Nano luciferase, SARS-CoV-2, Highly sensitive, Antigen detection, Automatic magnet chemiluminescence immune VCP-Eribulin assay (AMCA) Background Viruses cause most human infectious diseases. With the ecological and environmental changes, novel viral infectious diseases emerge continuously; viral diseases are becoming a more significant threat to health [1C3]. During the early stages of virus infection, rapid VCP-Eribulin detection and accurate identification of the pathogen can determine the source of infection and infection route, thereby enabling effective prevention and control of further spread [4, 5]. Nucleic acid test such as fluorescence quantitative polymerase chain reaction (qPCR) has been the standard method for many virus identifications because of their VCP-Eribulin high accuracy and high sensitivity [6C8], however, qPCR tests are complex and time-consuming, requiring special equipment, professional staff, and laboratories; thus, they cannot be used for rapid on-site/in-field detection. The immune chromatography assay is the most common means of rapid on-site detection, which detects the virus directly in a sample; the detection process is simple and fast [4]. However, due to low sensitivity, the accuracy of detection cannot be guaranteed; thus detection of virus antigens can only be used for an auxiliary diagnosis of virus infection [9C12]. Therefore, improving detection sensitivity is essential if we are to develop more accurate and rapid viral antigen detection methods. The sensitivity of viral antigen detection methods based on immune reactions is affected by a various factors, including the abundance of the target in the sample and the affinity of the detection antibodies for this target. Another factor is the intensity of the signal reporter [10C12]. Identifying new reporters that generate higher signal intensity, coupled with optimization of labeling strategies, may play an important role in the search for a new high- sensitivity virus antigen detection method. The biological reporter luciferase generates a high intensity signal over a wide linear range, and has a fast enzymatic reaction. It is used widely for gene expression and gene functional analyses, as well as for in vivo and in vitro imaging. With respect to serological detection, its wider linear range, faster enzymatic reaction, and higher detection sensitivity make it a better option than other enzyme-linked reaction [13]. Nano luciferase (Nluc) is a new kind of luciferase that generates a glow-type luminescence (signal half-life?>?2?h) with an activity 150-fold greater than that of either firefly (Photinus pyralis) or Renilla luciferase [13C15]. Using luciferase as reporter is expected to improve the sensitivity of virus antigen detection assays; however, no studies have reported detection of viral antigens using full-length antibodies labeled with Nluc. SARS-CoV-2 (value of?