Human respiratory syncytial virus (HRSV) is the most common etiological agent of acute lower respiratory tract disease in infants and can cause repeated infections throughout life. Human respiratory syncytial virus A (strain Long) major surface glycoprotein G (RSV-G), a member of the pneumoviruses glycoprotein G family, is also known as attachment glycoprotein G and membrane-bound glycoprotein (mG), which contains a linear heparin binding domain essential for virus attachment to the host. Concretely speaking, RSV-G can attache the virion to the host cell membrane by interacting with heparan sulfate, initiating the infection. Furthermore, RSV-G can also interact with host CX3CR1, the receptor for the CX3C chemokine fractalkine, to modulate the immune response and facilitate infection. Unlike the other paramyxovirus attachment proteins, RSV-G lacks both neuraminidase and hemagglutinating activities.