Human papillomavirus L1 capsid protein (types 6, 11, 16, 18, 31, 33, 45, 52, 58) (HPV L1)

The Human papillomavirus (HPV) L1 capsid protein is the primary structural component of the HPV virion, forming an icosahedral shell that protects the viral genome (UniProt P03101). It is essential for the viral life cycle, mediating attachment to host cell surface receptors like heparan sulfate proteoglycans to facilitate viral entry (PMID: 25173121). The L1 protein is highly immunogenic, particularly its surface-exposed loops which contain the epitopes targeted by neutralizing antibodies. In the 9-valent vaccine (Gardasil 9), recombinant L1 proteins from HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 are used as antigens (FDA, Gardasil 9 Label). These specific types are responsible for the majority of HPV-associated diseases, including cervical, anal, and oropharyngeal cancers, as well as genital warts (CDC, HPV Vaccination). The vaccine works by inducing a robust humoral immune response, creating a pool of antibodies that bind to the L1 protein and prevent the virus from infecting basal epithelial cells. The L1 protein's ability to self-assemble into non-infectious virus-like particles (VLPs) allows it to mimic the native virus's structure without containing viral DNA (PMID: 16439306). This target is a cornerstone of global public health efforts to eliminate cervical cancer and other HPV-related malignancies. Therapeutic strategies focusing on L1 are primarily prophylactic, as the protein is not expressed in high levels during the late stages of oncogenic transformation. Overall, the L1 capsid protein is the most successful target for preventing infection by both high-risk and low-risk HPV genotypes.

Other names

Major capsid protein L1HPV L1 proteinL1 major capsid proteinHPV VLPHuman papillomavirus major capsid protein

Induction of a humoral immune response resulting in the production of type-specific neutralizing antibodies that bind to the L1 protein and block viral attachment and entry into host cells (PMID: 16439306; FDA, Gardasil 9 Label).