Norovirus GII.4 capsid protein antigen (GII.4 norovirus antigen (commonly "GII.4 antigen" or "GII.4 VP1 antigen"))

The norovirus GII.4 capsid protein antigen is a structural protein forming the outer shell of human noroviruses in the GII.4 genotype, the predominant cause of acute viral gastroenteritis worldwide over the last several decades[1][2][3][4][5]. This antigen corresponds to the major capsid protein VP1, which self-assembles into icosahedral virus-like particles (VLPs) and is highly immunogenic, serving as the principal target for neutralizing antibodies and vaccine design[3][5][7]. The VP1 protein consists of a shell (S) domain and a protruding (P) domain; the latter is subdivided into the P1 and P2 subdomains, with the P2 subdomain being the most exposed and antigenically variable region, mediating binding to host histo-blood group antigens and containing key neutralizing antibody epitopes[2][4][5]. Antigenic drift in the P2 region under immune pressure contributes to ongoing emergence of novel variants and frequent global outbreaks[1][2][4][5]. There are currently no licensed therapeutics directly targeting this antigen, but it is the leading candidate molecule for VLP-based norovirus vaccines and therapeutic monoclonal antibody development[7].

Other names

Norovirus GII.4 antigenGII.4 VP1 antigenNorovirus GII.4 capsid proteinHuman norovirus genotype II, genotype 4 antigen

Elicitation of neutralizing antibodies that block virus binding to host cell histo-blood group antigens (HBGAs)[2][3][5][7] Blockade of viral entry by antibodies targeting conformational or linear epitopes in the P2 subdomain of VP1[2][5][6][7]