Respiratory syncytial virus attachment glycoprotein G, central conserved domain (RSV G CCD)

The Respiratory syncytial virus (RSV) attachment glycoprotein G, central conserved domain (CCD) is a critical, non-glycosylated region of the RSV G protein, typically encompassing amino acids 160 to 200 (Anderson et al., 2021). Unlike the hypervariable mucin-like domains that flank it, the CCD is nearly invariant across RSV subgroups A and B, making it an attractive target for broadly neutralizing therapies (Tripp et al., 2018). It contains a functional CX3C chemokine motif (aa 182–186) and a rigid cysteine noose structure that facilitates viral attachment to the host CX3C chemokine receptor 1 (CX3CR1) on airway epithelial cells (Bakre et al., 2017). Beyond its role in attachment, the CCD acts as a molecular mimic of the host chemokine fractalkine (CX3CL1), which disrupts normal immune cell recruitment and contributes to viral immune evasion (Harcourt et al., 2006). This domain also interacts with heparan sulfate proteoglycans to assist in viral binding to host cells (UniProt P03423). Therapeutic strategies targeting the CCD include monoclonal antibodies such as 3G12 and 3D3, which block the CX3C-CX3CR1 interaction and neutralize viral infectivity (Fedechkin et al., 2018). Vaccine candidates like BBG2Na and various nanoparticle-based immunogens have also been developed to elicit protective antibodies against this domain (Power et al., 2001). However, the CCD is naturally poorly immunogenic, presenting a significant challenge for vaccine design (Anderson et al., 2021). Targeting this domain is also intended to reduce the inflammatory pathology and airway dysfunction associated with RSV-mediated immune modulation (Tripp et al., 2018). Overall, the RSV G CCD represents a dual-function target that mediates both viral entry and the suppression of host antiviral responses (Bergeron & Tripp, 2021).

Other names

RSV G protein central conserved domainRSV G protein central conserved regionRSV G protein CCRRSV G protein cysteine nooseRSV G protein CX3C motif

Neutralization of viral attachment by blocking the interaction between the viral CX3C motif and the host CX3CR1 receptor, and inhibition of G-mediated immune modulation and inflammation.