What Is a Surface Antigen?

Surface antigen refers to the antigen surrounding the surface of the bacterial cell antigen, and its presence can interfere with the binding of the bacterial cell antigen to the corresponding antibody. The capsular antigen of pneumococcus, the surface antigen of some Gram-negative bacilli, such as the K antigen of E. coli, and the Vi antigen of typhoid. Surface molecules on the surface of lymphocytes that can be recognized by specific antibodies (such as monoclonal antibodies). Because surface antigens are produced during the differentiation of lymphocytes, they are also called differentiation antigens. Because monoclonal antibodies are used to recognize antigens, the names of monoclonal antibodies in different laboratories are different, so multiple names for the same antigen have appeared. In order to avoid confusion, the lymphocyte surface antigen was named after the differentiation group (CD) in 1983. So far, there are more than 130 kinds of antigens.

Surface antigen

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Surface antigen refers to the antigen surrounding the surface of the bacterial cell antigen, and its presence can interfere with the binding of the bacterial cell antigen to the corresponding antibody. The capsular antigen of pneumococcus, the surface antigen of some Gram-negative bacilli, such as the K antigen of E. coli and the Vi antigen of typhoid. Surface molecules on the surface of lymphocytes that can be recognized by specific antibodies (such as monoclonal antibodies). Because surface antigens are produced during lymphocyte differentiation, they are also called differentiation antigens. Because monoclonal antibodies are used to recognize antigens, the names of monoclonal antibodies in different laboratories are different, so multiple names for the same antigen have appeared. In order to avoid confusion, the lymphocyte surface antigen was named after the differentiation group (CD) in 1983. So far, there are more than 130 kinds of antigens.

Chinese name

Surface antigen

Foreign name

surface antigen

Definition

Surrounded by the appearance of bacterial cell antigens

Classification

Medical term

The polysaccharide component around the bacterial body is not heat-resistant and can block the reaction between the 0 antigen and the corresponding antibody.

Hepatitis B surface antigen (HBsAg) is the outer membrane protein of hepatitis B virus (HBV), which can appear early after infection with HBV. Positive hepatitis B surface antigen is a hallmark of HBV infection. It can be found in patients' blood, saliva, breast milk, sweat, tears, nasopharyngeal secretions, semen and vaginal secretions. Two to six months after infection with hepatitis B virus, positive results can be detected in the serum 2 to 8 weeks before the alanine aminotransferase is elevated. Most patients with acute hepatitis B can turn negative early in the course of the disease, and patients with chronic hepatitis B can continue to be positive for this indicator. ^[1]

In daily life, I often encounter some very healthy people who find that the hepatitis B surface antigen is positive in the examination, they think they have hepatitis B, and they are afraid to spread it to people around them. In fact, the hepatitis B surface antigen alone cannot be used to determine whether it is contagious. Whether it is contagious depends mainly on the degree of virus replication in the liver. If the replication of the virus is active and a large number of virus particles are released into the blood, the person's blood is highly infectious.