Monday, January 31, 2011

Biological challenges and technological opportunities for Respiratory Syncytial Virus Vaccine (RSV) Development

A recent paper published December 28, 2010 discusses the production of a vaccine against RSV. This virus does not currently have any good forms of treatment, and it is suggested that vaccination would be the best way to tackle the illness in the population. One major argument for producing a vaccine is that RSV is not known to have any intermediate host or animal reservoir and so successful vaccination could completely change the ecology of the disease. However, there are major challenges that scientists are encountering in producing a viable vaccine for RSV.

One barrier is the early age of infection of RSV. RSV is most common among infants who are an extremely immunological fragile population and cause an array of complications when it come to developing vaccines.

Another set of challenges has to be with the way RSV interacts and activates the immune system. RSV has the capacity to evade innate immunity by limiting type I interferon responses (IFN). Two RSV proteins, NS1 and NS2 (non-structural) are encoded at the beginning of the geonome and collaborate to inhibit IFN-associated genes. RSV also hs mechanisms to inhibit TLR signaling. The effect is especially bad for infants who have a weak innate immune response.

Other factors that present hurdles to vaccine development are that RSV does not produced adaptive immunity to prevent reinfection, there is a history of RSC vaccine-enhanced disease, and they lack an aminal model for RSV.

The two current solutions that are being worked on are live attenuated viruses. Live attenuated viruses are attractive because they can be given parentally or mucosally, which among infants is safe. Live attenuated RSV and replication-competent chimeric viruses are in advanced clinical trials.

- Lauren Platt

Source: Graham, B. Biological challenges and technological opportunities for Respiratory Syncytial Virus Vaccine (RSV) Development. Immunological Reviews. 2011. 239: 149-166.

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