China develops monoclonal antibody reference materials against COVID-19

China develops monoclonal antibody reference materials against COVID-19

A cured COVID-19 patient donates plasma at a blood donation vehicle in Wuhan, central China’s Hubei Province, March 12, 2020. (Xinhua/Fei Maohua)

Since the outbreak of the epidemic, the immunoassays based on IgM antibody and IgG antibody of the COVID-19 patients have been considered as an important supplement to the nucleic acid detection.

BEIJING, March 22 (Xinhua) — Chinese researchers have developed two monoclonal antibody reference materials to assist the detection for the novel coronavirus.

The two human IgG monoclonal antibody reference materials, developed by the National Institute of Metrology (NIM), have been approved as national reference materials by the State Administration for Market Regulation, according to a report by Science and Technology Daily.

Since the outbreak of the epidemic, the immunoassays based on IgM antibody and IgG antibody of the COVID-19 patients have been considered as an important supplement to the nucleic acid detection.

The new antibody reference materials, combined with the previously developed reference materials for COVID-19 nucleic acid testing, can further improve the accuracy of the detection, said Dai Xinhua, researcher from the NIM.

As of March 16, a total of 11 nucleic acid detection reagents and eight antibody detection reagents for the COVID-19 were approved by the National Medical Products Administration.

The specific antibody reference materials can provide an accurate and reliable guarantee for the development of the testing kits and detection reagents from different manufacturers, said the report. 


What It Is
An immunoglobulin test measures the level of certain immunoglobulins, or antibodies, in the blood. Antibodies are proteins made by the immune system to fight antigens, such as bacteria, viruses, and toxins.

The body makes different immunoglobulins to combat different antigens. For example, the antibody for chickenpox isn’t the same as the antibody for mononucleosis. Sometimes, the body may even mistakenly make antibodies against itself, treating healthy organs and tissues like foreign invaders. This is called an autoimmune disease.

The five subclasses of antibodies are:

  1. Immunoglobulin A (IgA), which is found in high concentrations in the mucous membranes, particularly those lining the respiratory passages and gastrointestinal tract, as well as in saliva and tears.
  2. Immunoglobulin G (IgG), the most abundant type of antibody, is found in all body fluids and protects against bacterial and viral infections.
  3. Immunoglobulin M (IgM), which is found mainly in the blood and lymph fluid, is the first antibody to be made by the body to fight a new infection.
  4. Immunoglobulin E (IgE), which is associated mainly with allergic reactions (when the immune system overreacts to environmental antigens such as pollen or pet dander). It is found in the lungs, skin, and mucous membranes.
  5. Immunoglobulin D (IgD), which exists in small amounts in the blood, is the least understood antibody.

IgA, IgG, and IgM are often measured together. That way, they can give doctors important information about immune system functioning, especially relating to infection or autoimmune disease.