The Nature and Effect of Superbug H1N1 Coursework

The Nature and Effect of Superbug H1N1 - Coursework Example HA molecules are particularly important in the development of the disease as they cause the preferential attachment to lung epithelial cells and the insertion of the virus contents into the host cell. Each protein in the virus has multiple subtypes. In human-infecting Influenza virus strains, there are three HA subtypes, H1, H2 and H3, while NA has two, N1 and N2. The different combinations of HA and NA make possible the multiple subtypes of Influenza viruses (Kimball, 2009). With the elucidation of the viral structure, it has since been discovered that there are multiple strains of the virus, and that they continually mutate and cross-infect swine, birds and humans. As commonly seen among viruses, HA, together with NA, genes mutate at a high rate, causing new strains to be seen infecting humans almost yearly. This phenomenon is referred to as the antigenic shift. In addition, Influenza virus strains undergo gene reassortment, in which two strains infecting the same bird or swine exc hange RNA strands to develop a new virus subtype that the human population has not been exposed before. Thus, this antigenic shift usually causes severe pandemics. For example, the 1957 H2N2 Asian flu pandemic after the 1918 H1N1 Spanish flu pandemic is believed to be caused by the simultaneous infection of a human-infecting subtype and a bird-specific H2N_ resulting to the reassortment of their genes that produced a new bird-specific subtype that can infect humans. In effect, this new H2N2 subtype is something the human population at that time has not been exposed before, causing many to have no immunity against the virus and to be susceptible to infection (Kimball, 2009). Because of the unique features of Influenza virus, current prophylaxis still involves multiple vaccinations, with the composition of multivalent shots varied annually to confer protection against strains guessed to be most infective during the coming season. Thus, prolonging and ensuring the effectiveness has bee n the focal point of many researches. A promising approach is the development of vaccines that can induce the production of antibodies that are specific against multiple HA subtypes. Throsby and his colleagues (2008) paved the way for such approach when they identified human antibodies that can bind to H1, H2, H5, H6, H8, and H9. They referred to this antibody as CR6261 (Eckiert et al., 2009). CR6261 AGAINST H1N1 AND OTHER SUBTYPES What makes CR6261 different from other antibodies that confer resistance to only one subtype of Influenza? Eckiert et al. (2009) tried to elucidate the 2.2 and 2.6A crystal structure of the antigen-binding portion (Fab) of CR6261, as well as the CR6261 Fab complexed with heterotypic HAs from human 1918 H1N1 pandemic virus and avian H5N1 virus. Although it was not mentioned in the study if there is any purpose in choosing H1 and H5 instead of the other subtypes, the choices probably served the most purpose because H1 has a history in causing a pandemic (19 18 H1N1 Spanish flu), and H5 has a likelihood to infect and cause death among humans, who are mostly unexposed to such type of Influenza (Kimball, 2009). However, it is most ideal if the study