GFP Labelled Human Respiratory Syncytial Virus (Strain B1)

Respiratory syncytial virus (RSV) is a highly contagious pathogen primarily transmitted through respiratory droplets or direct contact with contaminated surfaces. The virus enters the host through the eyes, nose, or mouth and replicates in the epithelial cells of the upper and lower respiratory tract. RSV is seasonal, with outbreaks typically occurring in winter and early spring in temperate regions. Infants, the elderly, and immunocompromised patients are particularly susceptible to severe disease, such as bronchiolitis or pneumonia. Its pathogenesis involves viral replication leading to epithelial cell damage, which subsequently triggers an inflammatory immune response. This results in airway obstruction, mucus hypersecretion, and edema. Notably, RSV can evade host immunity by inhibiting interferon production and modulating immune cell activity, thereby promoting lifelong reinfection.

RSV is an enveloped, negative-sense, single-stranded RNA virus belonging to the Pneumoviridae family. Its virions are pleomorphic, ranging in diameter from 150 to 300 nanometers, and have a lipid bilayer envelope studded with glycoprotein spikes. These spikes are composed of an attachment protein (G), which binds to host cell receptors, and a fusion protein (F), which mediates viral entry into host cells via membrane fusion. Its genome is approximately 15.2 kb long and encodes 11 proteins, including the nucleocapsid (N), phosphoprotein (P), and RNA-dependent RNA polymerase (L), which are essential for replication. This genome is tightly bound to the N protein to form a helical nucleocapsid. Unlike segmented RNA viruses, RSV''s nonsegmented genome reduces the risk of recombination but requires precise transcriptional regulation. The matrix protein (M) supports virion assembly, while the nonstructural proteins (NS1 and NS2) antagonize the host''s antiviral defense mechanisms.