Human rhinovirus 14 (HRV14), the causative agent of the common cold, is a member of a family of animal viruses-the picornaviruses-whose other members include the polio, hepatitis A, and foot-and-mouth disease viruses. The HRV14 virion consists of an icosahedral protein shell, or viral capsid, surrounding an RNA core. The capsid is made up of 60 copies of each of four structural proteins, VP1-VP4. Based on crystal structure data, VP1, VP2, and VP3 compose the viral surface, whereas VP4 lies interior at the capsid/RNA interface.