Epstein–Barr virus viral-capsid antigen

Epstein–Barr virus viral-capsid antigen is an immunogenic antigen derived from the protein shell of the Epstein Barr Virus.

Epstein Barr Virus (EBV) causes the illness referred to as Mononucleosis. In the infectious stage of this illness, individuals will have Epstein Barr viral capsid antigens (EBV-VCA) in their mouth and blood. The viral capsid of a virus is the complex of proteins that surrounds the genetic material inside the virus. Epstein Barr virus capsid antigens (VCA) are any sections of the viral capsid that the hosts' antibodies bind to. The hosts, or individuals infected with the virus, will produce antibodies to target these Epstein Barr viral capsid antigens. IgG VCA antibodies will be produced during the early stage of the EBV infection. In contrast, IgM VCA antibodies will be produced at later stages on the infection.

Testing
Several types of tests are used to diagnose individuals with Mononucleosis. For immunocompetent individuals, antibodies targeting the viral capsid antigen have been found to be more effective and accurate than alternative testing methods. Immunocompromised individuals will not have the same results to VCA IgG and IgM antibody tests as immunocompetent individuals.