[Published: 05 June 2003 Source: Anti-Infective Drug News]

A new prototype vaccine developed by researchers at the Wistar Institute might be able to protect recipients not only against this year's strains of the virus, but also against those yet to come, possibly eliminating the need for an annual treatment. A report on the new findings appears in the 2nd June issue of Vaccine (2003;21:2616-2626).

Current flu vaccines trigger an immune response to a pair of prominent viral-coat proteins that mutate constantly, which is why last year's flu vaccine is ineffective against this year's flu strains. The experimental vaccine contains an engineered peptide that mimics a third, smaller viral-coat protein, called M2, that remains largely constant from year to year.

Mice vaccinated with the vaccine generated a strong antibody (Ab) response against M2. In fact, the mice generated a more powerful Ab response to the vaccine than to infections by the flu virus itself. The experimental vaccine was administered twice intranasally to mice. After vaccination, a steep rise in M2-specific Abs was seen in blood samples from the mice, and the mice exhibited significant resistance to viral replication in the respiratory tract.

The researchers are also looking into whether the M2 element of the virus might begin to mutate in the presence of the anti-M2 Abs generated by the new vaccine. Their concern is that the observed viral stability in the M2 region of the flu virus may simply be a reflection of the fact that the immune system does not mount a vigorous response to it, so that evolutionary pressure on that region of the virus is not great.
 

Source: Anti-Infective Drug News, copyright Espicom Business Intelligence. For article reprint permission please click here.

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