Having the sniffles is no fun, especially when you are a kid. However, the cause of most lower respiratory tract infections in children is by respiratory syncytial viruses (RSV), a virus that has thus far eluded attempts to generate effective vaccines. RSV vaccine development has been frustrated by the difficulty in achieving a balance between safety and immunogenicity as candidate vaccines using inactivated-whole virus triggered enhanced disease in infants and young children. How these viruses evade or even alter immune responses was not clear, but researchers at the National Institutes of Health report in the August issue of Nature Immunology (Vol. 2, No. 8, pp. 732-738) one way by which RSV tricks the immune system.
Ralph Tripp and colleagues have found that a RSV surface protein, the G glycoprotein, acts as a molecular mimic of a naturally occurring chemical signal that instructs cells of the immune system. First, this G glycoprotein, through a surface protein known as the chemokine CX3CR1 receptor, triggers movement of leukocytes. Then, the G glycoprotein alters normal leukocyte responses to infection, but how this is actually achieved is still unknown. Subversion by the G glycoprotein may slow the body’s ability to get rid of the virus or alter local inflammatory responses such that it provokes symptoms typical of respiratory infections. Thus, RSV actively lures and modulates the very cells that combat infections.
Ralph A. Tripp
Centers for Disease Control and Prevention
National Center of Infectious Diseases
Division of Viral and Rickettsial Diseases
Mailstop G-09, 1600 Clifton Road
Atlanta, GA 30333
Tel: (+1) 404-639-3427
Fax: (+1) 404-639-1307
(C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza