Foot-and-Mouth Disease Virus intact capsid (FMDV 146S)

The Foot-and-Mouth Disease Virus (FMDV) intact capsid, also known as the 146S particle, is the structural shell of the virus that encapsulates its single-stranded RNA genome (1.1.1, 1.3.4). It is composed of 60 protomers, each containing four structural proteins: VP1, VP2, VP3, and VP4, which assemble into an icosahedral structure (1.1.2, 1.3.5). The capsid's primary biological function is to protect the viral genome and facilitate entry into host cells by binding to integrin receptors through a conserved Arg-Gly-Asp (RGD) motif located on the VP1 G-H loop (1.1.4, 1.3.3). FMDV causes a highly contagious and economically devastating disease in cloven-hoofed animals, characterized by fever and vesicular lesions (1.3.2, 1.3.4). The 146S particle is the essential component of conventional inactivated vaccines, as its structural integrity is required to induce a potent neutralizing antibody response (1.1.1, 1.5.3). However, the capsid is notoriously unstable, readily dissociating into less immunogenic 12S pentamers when exposed to heat or acidic conditions, which poses significant challenges for vaccine manufacturing and storage (1.1.2, 1.4.2). Therapeutic and preventative strategies focus on using inactivated 146S particles as vaccines, developing neutralizing antibodies that block entry, and engineering more stable capsids to improve vaccine shelf-life and efficacy (1.4.1, 1.4.3).

Other names

FMDV virion146S particleFMDV 146S antigenFoot-and-mouth disease virus capsidFMDV icosahedral shell

The intact capsid (146S) serves as the primary immunogen in vaccines, eliciting neutralizing antibodies that bind to the capsid surface (particularly the VP1 G-H loop) to block viral attachment to host integrin receptors and prevent subsequent uncoating and RNA release (1.1.2, 1.1.4, 1.4.4).