Main Mechanism of Antigen into Blood
When SARS-CoV-2 invades the lung cells, it will express a large amount of self protein to reassemble the virus particles, causing cell damage and forming inflammation. The virus protein expressed in excess, as well as the virus protein released from the disintegration of virus particles killed by the body in the lesions, will enter the blood circulation through the vessel wall with increased permeability due to inflammation in the lesions.
Mechanism of Reduction and Elimination of Antigen in Blood
- The virus antigen will stimulate the patient’s body to produce the corresponding antibody, and said antibody will produce the specific combination with the corresponding antigen, forming the antigen antibody immune complex to be cleared by the body’s immune system. As the amount of antibody produced by the patient increases gradually, the amount of antigen cleared will also increase synchronously.
- With the activation of the immune system, the ability of killing the virus is enhanced, the viral load in the body will gradually decrease, and the production of virus and blood antigen will also gradually decrease.
Significance of Combined Detection of Antigen and Antibody in Blood
- The detection of antigens in blood can effectively make up for the “window period” of antibody detection.
- The detection of antibody in blood can avoid the problem that antigen can not be detected in the middle and
later stages of infection.
- The combined detection of antigen and antibody in blood can verify each other at different disease stages,
and provide complete serological evidence for the diagnosis of COVID-19.