Unique tropism and entry mechanism of mumps virus

Mumps virus (MuV) is an important human pathogen that causes parotitis, orchitis, oo-phoritis, meningitis, encephalitis, and sensorineural hearing loss. Although mumps is a vaccine-preventable disease, sporadic outbreaks have occurred worldwide, even in highly vaccinated pop-ulations. MuV not only causes systemic infection but also has a unique tropism to glandular tissues and the central nervous system. In general, tropism can be defined by multiple factors in the viral life cycle, including its entry, interaction with host factors, and host-cell immune responses. Although the underlying mechanisms of MuV tropism remain to be fully understood, recent studies on virus–host interactions have provided insights into viral pathogenesis. This review was aimed at summarizing the entry process of MuV by focusing on the glycan receptors, particularly the recently identified receptors with a trisaccharide core motif, and their interactions with the viral attachment proteins. Here, we describe the receptor structures, their distribution in the human body, and the recently identified host factors for MuV and analyze their relationship with MuV tropism.