Coxsackievirus A6 capsid conformational epitopes (CVA6 capsid epitopes)

Coxsackievirus A6 (CVA6) is a non-enveloped, positive-sense single-stranded RNA virus and a primary causative agent of hand, foot, and mouth disease (HFMD), particularly associated with atypical clinical presentations like eczema coxsackium (Xu et al., 2017). The CVA6 capsid conformational epitopes are complex three-dimensional structures formed by the folding and assembly of structural proteins VP1, VP2, and VP3 into an icosahedral shell. These epitopes are critical for viral pathogenesis as they often encompass the binding sites for the host cell receptor KREMEN1, which is essential for viral entry (Staring et al., 2018). Because these epitopes exist only in the native, quaternary structure of the virus, they are the primary targets for potent neutralizing antibodies elicited by natural infection or experimental vaccines. Therapeutic development focuses on these sites to create monoclonal antibodies and inactivated vaccines that can block viral attachment or prevent the uncoating process required for genome delivery. However, the high mutation rate of CVA6 presents a challenge for long-term efficacy, as minor changes in the capsid sequence can alter these conformational sites and allow the virus to escape immune detection (Yang et al., 2020).

Other names

CVA6 conformational epitopesCoxsackievirus A6 neutralizing epitopesCVA6 capsid surface antigensCVA6 quaternary epitopes

Neutralizing antibodies bind to these conformational epitopes to sterically hinder the interaction between the viral capsid and host receptors, such as KREMEN1, or to stabilize the capsid structure to prevent the pH-dependent uncoating and release of the viral RNA genome (Xu et al., 2017; Staring et al., 2018).