Thursday, May 21, 2009

FLU: SEARCH OF A UNIVERSAL VACCINE



The search for a universal vaccine that can protect the individual whole-life against all strains of seasonal influenza viruses, begins to take shape. When someone is vaccinated their immune system develops antibodies that attack a viral surface protein called hemagglutinin. A problem, because vaccination against certain viral strain will not generate antibodies against another, because the hemagglutinin area involved is the changing speed of the virus. I) So the strategy is to develop a vaccine to generate antibodies against non-variables areas, common to all strains. Fortunately, these variable parts exist: they are just inside the virus, out of reach of antibodies. For example, there is an internal protein (M2), slightly protruding outwards from the virus. VaxInnate, try combining the outer part of the M2 with a bacterial protein to stimulate the immune system. For the moment, in human volunteers who have developed antibodies to M2, was found not fully protect against infection. There is other non-variable regions in the external viral hemagglutinin, that have already generated in mice, antibodies effective against several influenza strains including the 1918. Other areas of study, includes non-variables zones located inside the virus : a nucleoprotein recruiting killer T cells capable of killing infected cells before they generate new viruses. II) Dynavax is developing a vaccine capable of generating antibodies against the M2 protein and capable to recruit killer cells. III) Although expensive, alternative is to use antibodies against influenza viruses.

VACUNA UNIVERSAL

La búsqueda de una vacuna universal, capáz de proteger al individuo -toda la vida- contra todas las cepas estacionales de los virus de la influenza, empieza a materializarse. Cuando alguien es vacunado su sistema inmune desarrolla anticuerpos que atacan una proteína viral superficial llamada hemaglutinina. Un problema, porque la vacunación contra cierta cepa viral generará anticuerpos que no servirán contra otra, porque el area implicada de la hemaglutinina es la parte cambiante, mas velóz del virus. I) De modo que la estrategia es desarrollar una vacuna generadora de anticuerpos contra partes no variables, que sean a la véz comunes a todas las cepas. Felizmente, esas partes poco variables, existen, solo que están en el interior del virus, fuera del alcance de los anticuerpos. Por ejemplo, existe una proteina interna (M2), que protruye un poco hacia el exterior del virus. VaxInnate, intenta combinar la parte externa del M2 con una proteina bacteriana a fin de estimular el sistema immune. De momento, en voluntarios humanos que han desarrollado anticuerpos contra M2, se ha comprobado que no protegen totalmente contra la infección. Existe otra región no variable en la parte externa viral, en zonas de la hemaglutinina, que en ratones han generado ya, anticuerpos eficaces contra varias cepas incluida la influenza de 1918. Otras areas de estudio, incluyen proteinas no variables ubicadas al interior del virus : nucleoproteinas reclutadoras de celulas T killer capaces de matar celulas infectadas antes que generen nuevos virus. II) Dynavax, esta desarrollando una vacuna capaz de generar anticuerpos contra la proteina M2 y capaz de reclutar celulas killer. III) Aunque costosos, otra alternativa es emplear anticuerpos contra los virus de la influenza.

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