Norovirus antigen

Norovirus antigens are **structural and nonstructural proteins**—primarily the **major capsid protein VP1**—expressed by noroviruses, which are non-enveloped, positive-sense single-stranded RNA viruses of the Caliciviridae family[6][5][3][7]. The main immunologically relevant antigen is VP1, which self-assembles into virus-like particles and contains distinct domains (shell, P1, P2), with the P2 domain highly exposed and mediating binding to **histo-blood group antigens (HBGAs)**, which serve as host cell attachment factors[1][7][2]. Other viral antigens include the minor capsid protein (VP2) and various nonstructural proteins (e.g., RNA-dependent RNA polymerase, protease, NTPase), all of which can be recognized by the host immune system[5][7]. While essential for immune recognition and vaccine development, **norovirus antigens themselves are not a druggable therapeutic target**; rather, they are used primarily for diagnostics, immunological studies, and as vaccine immunogens[7]. Noroviruses are a major cause of epidemic acute gastroenteritis globally, and antigenic diversity (especially in the VP1 P2 domain) leads to extensive strain variation and immune escape, presenting a key challenge for vaccine development[3][7][5]. **Note:** - "Norovirus antigen" refers to the viral proteins as immunological targets, not a single protein or a human or microbial drug target (e.g., receptor, enzyme, transporter)[7][5]. - VP1 and associated antigens do not constitute a classic drug target for small molecules or biologics, though they are crucial in serodiagnostics and vaccine research. - Histo-blood group antigens are the *host* attachment factors, not viral antigens[1][7]. **This entry is marked as incorrect ("is_incorrect: true")** since norovirus antigens collectively are not a target in the sense of a receptor/enzyme/transporter, but rather the immunogenic proteins derived from the virus. The correct structured information should use the precise viral protein (such as "Norovirus major capsid protein VP1") if specificity is needed.

Other names

Norovirus capsid antigenNorovirus VP1Norovirus major capsid proteinHuman norovirus antigenNorwalk antigen

Antibody neutralization (for vaccines/antibody therapies), Elicitation of humoral immune response