SNV GLYCOPROTEIN

SNV GLYCOPROTEIN Full Name

Hantavirus Glycoprotein

SNV GLYCOPROTEIN Introduction

Sin Nombre virus (SNV) glycoprotein complex consists of the two envelope glycoproteins Gn and Gc, encoded by the M segment of SNV, the predominant cause of hantavirus pulmonary syndrome (HPS) in North America. The deer mouse (Peromyscus maniculatus) is the primary reservoir host. The M segment polyprotein precursor is proteolytically cleaved to generate Gn (approximately 71 kDa) and Gc (approximately 56 kDa), both type I transmembrane glycoproteins that heterodimerize in the endoplasmic reticulum and traffic to the Golgi apparatus for post-translational glycosylation and virion budding. SNV glycoproteins share approximately 75–80% amino acid identity with other New World hantavirus glycoproteins such as ANDV and New York-1 virus (NY-1V), but considerably less with Old World hantaviruses. Gn forms the external lattice scaffold on the virion surface and mediates receptor attachment, while Gc contains the class II fusion machinery responsible for pH-triggered membrane fusion during cell entry. The Gn/Gc complex represents the principal target of virus-neutralizing antibodies.

Figure 1. Mechanistic basis for potent neutralization of Sin Nombre hantavirus by a human monoclonal antibody.

SNV glycoproteins mediate cell entry through engagement of αvβ3 integrin, the primary receptor used by New World hantaviruses, which is abundantly expressed on vascular endothelial cells and platelets. The Gn head domain binds directly to the PSI domain of the β3 integrin subunit, initiating clathrin-mediated endocytosis. Within acidified endosomes, Gc undergoes a dramatic conformational rearrangement from a prefusion dimer to a post-fusion trimer, inserting its fusion loop into the endosomal membrane to drive viral-cytoplasmic membrane merger. The αvβ3 integrin tropism of SNV glycoproteins directly contributes to the pulmonary endothelial targeting and capillary leak syndrome that characterize HPS. Beyond entry, SNV Gn suppresses innate immune signaling by inhibiting RIG-I/MAVS-dependent interferon induction and blocking TBK1 activation. The Gn-Gc heterodimer is the primary target of neutralizing antibody responses; monoclonal antibodies directed against conformational epitopes on both Gn and Gc can neutralize SNV in vitro and protect against lethal challenge in animal models. Limited cross-neutralization between SNV glycoproteins and those of Old World hantaviruses reflects the substantial antigenic divergence between these groups.

SNV glycoproteins are central to vaccine design and immunotherapeutic development for HPS prevention in North America. Several vaccine platforms targeting SNV Gn/Gc have been evaluated preclinically, including DNA vaccines encoding the M segment, recombinant adenovirus serotype 5 vectors, and virus-like particle (VLP) formulations. A recombinant vesicular stomatitis virus (rVSV) vector expressing SNV glycoproteins demonstrated complete protection in hamster challenge models. Monoclonal antibodies targeting conserved Gc fusion loop epitopes have shown cross-neutralizing activity against multiple New World hantaviruses and represent promising candidates for post-exposure prophylaxis, particularly for laboratory and healthcare workers with known exposures. For diagnostics, recombinant SNV Gn/Gc proteins are used in species-specific confirmatory ELISAs and focus reduction neutralization tests (FRNT) to distinguish SNV infection from other North American hantaviruses such as Bayou virus and Black Creek Canal virus. No licensed SNV vaccine or antiviral exists, and the high HPS case fatality rate of 35–40% underscores the urgent need for effective countermeasures. Structure-guided immunogen design based on high-resolution Gn/Gc structures is a promising strategy for next-generation hantavirus vaccine development.

Alternate Names for SNV GLYCOPROTEIN

Glycoprotein; glycoprotein

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