At present, the detection of COVID-19 mainly relies on nucleic acid testing, which has high requirements on testing equipment, laboratory standards, and operators. Generally, it is difficult for the top three hospitals to complete the test. Therefore, the establishment of rapid and accurate specific detection methods and antigen self-test are of great significance to the control of the epidemic. Antibody and antigen test kits may achieve high-throughput screening of viruses.
As we all know, the novel coronavirus is a single-stranded RNA virus, which itself contains only genetic material, The genetic material is the "soul" of the virus. And the process of virus infecting cells is llike "occupying someone else's body", and the assembly is completed through "instructions" of genetic material.
After the novel coronavirus approaches the cell, it will use its own genetic material to synthesize a series of proteins and complete the transformation by using the "body" of the cell. Therefore, the novel coronavirus does not have RNA alone, it will also have spike protein(S), nucleocapsid protein (N), membrane protein (M), etc., and the RNA is wrapped inside.
In the structure of the novel coronavirus, two types of proteins are very important:
One is the spike protein (S) called "crown". The S protein can recognize the receptor ACE2 on the cell surface, and then enter the cell to infect, so the S protein determines the infection ability of the new coronavirus. Through the analysis of the atom map of the new coronavirus S protein, it is found that its binding force to the receptor ACE2 is 10-20 times stronger than that of SARS.
Another protein is the nucleocapsid protein (N). N protein is the most abundant protein in coronaviruses and is highly conservative. In the process of virion assembly, N protein is combined with viral RNA to form a spiral nucleocapsid; and is related to viral genome replication and regulation of cell signaling pathways. Therefore, N protein is used as a diagnostic test tool for novel coronavirus and the basis of immunological rapid antigen test kit.
In summary, the novel coronavirus protein antigen kit is expected to achieve accurate diagnosis.
The viral protein antigen kit is composed of high-affinity monoclonal antibodies, has good specificity, high sensitivity, and can realize mass production with small batch-to-batch difference. After laboratory verification, it is expected to further improve the detection rate and accuracy of clinical samples, and solve the problem of false negative nucleic acid detection.
The main thing of the rapid antigen test kit for new coronavirus protein is to break through the key technical bottleneck of the inactivation of clinical samples and the degeneration of the virus, which leads to the decrease of detection sensitivity. Inactivation first and then detection is expected to achieve rapid high-throughput detection under ordinary biosafety conditions, and solve the bottleneck of clinical sample detection.