Florres-Munguía ME, Vázquez-Moreno L, Ramos-Clamont Montfort G

Language: Spanish
References: 120
Page: 74-87
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ABSTRACT

The ability of influenza A virus hemagglutinins (HA) to recognize specific carbohydrates located in vertebrate cells is the signal that allows virus attachment and replication at viral infection. This biological recognition also permits viral maintenance in their natural reservoir, wild aquatic birds or other spices. Receptor binding specificity of HA is dependent on the species of origin. In birds, influenza virus binds to glycoconjugates that contain α 2,3-linked sialic acid found in avian intestinal cells. To cross the species barrier and infect human cells, HA specificity must change to bind to glycoconjugates containing α 2, 6-linked sialic acid. This apparently simple change allows the avian influenza virus to replicate in the human respiratory system. Avian influenza virus may acquire HA genes from a human pathogenic strain, by passing through an intermediate host, the pig, which contains both α (2,3) and α (2,6) sialic acid in the respiratory epithelium and is therefore susceptible to both avian and human influenza. Since influenza virus has a segmented genome, mutations and or recombination events in viral genes can readily occur if a cell is infected with two different viruses. Furthermore, there is now evidence that some avian viral strains can infect human cells without intermediate hosts. These new strains are in continue evolution and can accumulate mutations leading to a possible influenza pandemic.

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