Human papillomavirus type 16 and type 18 major capsid protein L1 (HPV16 L1 protein, HPV18 L1 protein)

The L1 protein is the major structural component of the HPV viral shell, forming pentameric capsomers that self-assemble into highly immunogenic virus-like particles (VLPs). Recombinant L1 from HPV type 16 and 18 is the active antigen in licensed prophylactic vaccines, which induce potent antibody-mediated protection against infection. L1 mediates early interactions with host cell surface receptors, facilitating viral entry into epithelial cells and capsid stability. Sequence variation among HPV types is concentrated in L1 surface loops, which are the principal target of neutralizing antibodies, underscoring its centrality for cross-type immune protection and the design of polyvalent vaccines. Although L1 is not oncogenic nor a driver of malignancy per se, its presence in virion structure is critical for viral transmission and is indirectly implicated in disease progression through facilitating infection by cancer-associated HPV types. Vaccination targeting L1 has led to a dramatic reduction in the prevalence of cervical and other HPV-associated cancers globally.

Other names

HPV16 L1HPV18 L1HPV L1 capsid proteinMajor capsid protein L1

Induction of neutralizing antibodies that block HPV virion attachment and entry into host epithelial cells by targeting L1 epitopes on VLPs Prevent infection by high-risk HPV types 16 and 18