The 2019 novel coronavirus, on January 12, 2020, the World Health Organization officially named it 2019-nCovid. Coronaviruses are a large family of viruses that are known to cause colds and more serious diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS). The new coronavirus is a new strain of coronavirus that has never been found in the human body before.

On January 15, 2021, a variant of the new coronavirus from Brazil has been discovered in the UK. On February 21, according to a report from Russia Today, Indian health officials stated that as many as 240 new variants of the new coronavirus strain have been discovered in various parts of India, and active countermeasures are needed.

The 2019 Novel Coronavirus (SARS-COV-2) is a type of virus that is spherical in shape, has protrusions on its surface, and looks like a “crown” under electron microscope. SARS-COV-2 is composed of protein and RNA, and its membrane surface is mainly composed of three structural proteins: Spike Protein (S), Envelope Protein (E) and Membrane Protein (M) ; Inside the virus is RNA, the nucleic acid material responsible for virus reproduction, which is wrapped and protected by nucleoprotein (N).

Raw materials for SARS-COV-2 Antigen Test

SARS-COV-2 antigen detection is based on the immunological reaction of antigen and antibody to detect the presence of new coronavirus in the human body. The types of test samples currently approved in the market include: nasopharyngeal swabs, saliva, sputum, oral secretions, blood, etc. With the optimization of the performance of raw materials and product processes, the specificity and sensitivity of antigen detection reagents are getting higher and higher, which can be comparable to nucleic acid detection reagents. However, the rapid detection reagents for antigens are convenient to operate, fast for detection, and do not require professional operators and equipment. Therefore, in some occasions, especially the opening of home self-tests, rapid antigen detection reagents can be effective as a new covid-19 diagnosis and screening. tool. The SARS-COV-2 NP monoclonal antibody and SARS-COV-2 S-RBD monoclonal antibody developed and produced by Bio-mapper can be used in the development and production of antigen detection reagents. All recommended pairs have been tested on clinically positive samples, virus lysates and inactivated vaccines, and have shown very good performance in different test samples. Of course, the antibody screening work is not over, and Mai Yue Biological will continue to screen new antibody pairs for verification and continue to maintain communication with customers, keeping an eye on clinical changes at any time.

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Test sample type：nasopharyngeal swabs, saliva, sputum, oral swab,Anterior nasal swab

The profermance：Sensitivity>90%;Specificity>95%

Detection Limit：Recombinant Antigen：<10pg

Virus culture：dilution 10000 times

Inactivated virus：1.51 ˟10 TCID50/ml

Applicable method:Double antibody sandwich method, biotin amplification system Applicable platform:Latex, colloidal gold

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After SARS-COV-2 virus enters the human body, B cells will produce different types of antibodies. In the early stage of infection (7 days of initial illness), the human body will produce IgA and IgM antibodies, but they can only survive in the body for about 30 days. IgG antibodies are produced late, but they can stay in the body for several months. At the same time, the titers of IgG antibodies in the recovery phase are several times higher than the gradient in the acute infection phase. Therefore, the detection of SARS-CoV-2 IgG/IgM (IgA) can be used for disease course monitoring, epidemiological investigation, and large-scale preliminary screening. For the detection of different types of antibodies, the process and stage of the disease can be distinguished. The N protein (prokaryotic expression), the S1 protein (eukaryotic expression), the RBD protein (eukaryotic expression), mouse anti-human IgG monoclonal antibody, mouse anti-human IgM monoclonal antibody, mouse Anti-human IgA monoclonal antibody can be used for SARS-COV-2 IgG, IgM, IgA antibody typing detection, with high sensitivity and high specificity. Good antigen/antibody can greatly improve the accuracy of detection reagents. As the virus continues to mutate, Biomapper has designed and developed antigens for different immune strains to respond to different mutant strains at any time. At the same time, Biomapper has also developed two sufficient proteins (N protein and S protein) for the positive quality control of new crown antigen detection.

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After the human body is vaccinated, it will produce a protective antibody to deal with the virus that enters the human body again. This protective antibody is called a neutralizing antibody. The virus surface protein is the key(RBD protein) for the virus to enter the cell. It can open the “lock” of the cell receptor protein (ACE2 protein) to enter the cell and initiate its replication process. The body’s protective antibody response is precisely by recognizing and blocking the combination of this “key” and “lock” to block the virus from entering the cell. Now the key target of vaccine development is the “key” to the covid-19 virus. How to monitor the effect of the vaccine after vaccination will become a new demand point. How to grasp effective, scientific, and truly protective antibodies will be the most important key point of this product. The ACE2 protein is an important gateway for the virus to enter the human body. It is based on the structural binding between the ACE2 protein and the RBD protein, and the specific binding between the RBD antibody and the RBD protein. At the same time, the current vaccine targets are all against the RBD protein, ACE protein Competitively binding to RBD protein with RBD antibody will be an effective way to detect neutralizing antibody. The ACE2 protein and RBD protein, which are closer to the natural structure, are the prerequisite for the efficient combination of these two proteins. The ACE2 protein and RBD protein developed and produced by Mai Yue Biological are expressed and purified in HEK293 cells, and they are closer to the natural structure. The combination of the two is more in line with the structural combination of the lock and key of the natural virus. At the same time, the RBD monoclonal antibodies, RBD polyclonal antibodies and RBD recombinant antibodies screened by the company can be used as a positive quality control for the neutralizing antibody project. Provide effective tools for the development of the project.

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Raw materials for RBD IgG Antibdy test(Capture method)

There have three kinds of vaccine.mRNA vaccine, adenovirus vector vaccine and Inactivated vaccine. All vaccine have the RBD epitopes which are able elicit neutralizing antibodies in SARS-COV-2 recent stduies. So detecting the RBD IgG antibody will help us to study whether vaccine activity.The test cassette consists of: 1)a burgundy colored conjugate pad containing SARS-COV-2 S-RBD antigen conjugated with colloid gold (SARS CoV-2 conjugates) and mouse IgG-gold conjugates, 2) a nitrocellulose membrane strip containing a test band (T band) and a control band (C band). The test band is pre-coated with Mouse anti-human IgG antibody for capture bind to RBD with neutralizing antibody , in order to detection the RBD antibody in serum, plasma and whole blood. The C band is pre-coated with goat anti mouse IgG.

When an adequate volume of test specimen is dispensed into the sample well of the test cassette, the specimen migrates by capillary action across the cassette. If there is antibody producing after vaccine, the RBD antibody will be conjugated with RBD antigen, than the Mouse anti-human IgG antibody can bind to RBD antigen with Neutralizing Antibody. So the test line will be colored. If no antibody produced, the RBD antigen will not bind to Mouse anti-human IgG antibody , the test line will not be colored. These combo cassette can distinguish the source of the antibody, which is very important for detecting the effect of the vaccine.

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