Bird flu vaccine target found27th April 2009
A new study has discovered how the human body responds to the H5N1 avian influenza virus, paving the way for possible new developments in vaccines against the disease.
Researchers looked at blood samples from patients from Vietnam who were recovering from infection with bird flu, taking antibodies from them and observing how they reacted to various proteins found on H5N1.
The study gives a clearer picture of exactly what part of the bird flu virus is seen by the immune system once a person becomes infected.
One particular protein, PB1-F2, was identified as a potential target for attack by immune systems to stop the spread of the virus, and therefore for the development of future vaccines.
Such techniques can lead to new tools for testing the potential protective activity of vaccines already under development.
Karen Midthun, acting director of the US Federal Drug Administration’s Center for Biologics Evaluation and Research, said the findings could also lead to new tests to detect infections, and improved therapies.
The transmission of highly pathogenic avian H5N1 viruses from poultry to humans have sparked efforts to prepare effective vaccines and therapies including polyclonal or monoclonal antibodies, the team wrote in the preamble to their study, which was published in the online open-access journal PLoS Medicine.
But researchers pointed to a lack of information on protective immune responses against the viruses, and said they hoped to characterise the B cell responses in convalescent individuals as a way of helping to design future vaccines and treatments.
Researchers in the study adapted an existing technique using genetically modified viruses, or phages, to create fragments representing the proteins found in the H5N1 virus.
When the proteins were mixed with the antibodies from the recovering Vietnamese patients, they were able to observe which fragments were attacked by the patient's antibodies.
Researchers believe that PB1-F2 contributes significantly to the virus’s ability to cause disease, which has never been observed to cause such an immune response before, according to senior article author Hana Golding.
Lead author Surender Khurana and co-authors Yonaira Rivera, Jody Manischewitz, and Lisa King also contributed to the study, together with Kanta Subbarao, Amorsolo Suguitan Jr of the National Institute of Allergies and Infectious Diseases and Cameron Simmons of the Hospital for Tropical Diseases in Vietnam's Ho Chi Minh City, Vietnam. Biomedicine researcher Antonio Lanzavecchia from Switzerland was also named as co-author.
Avian influenza has infected more than 400 people worldwide since 2003, about 60% of whom have died.
So far, no cases of avian flu have been reported in the United States.
While most avian flu infections in humans involve people who have come into contact with infected poultry, experts fear the virus could mutate to be transmissible between people, sparking a global pandemic.
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Title: Bird flu vaccine target found
Author: Luisetta Mudie
Article Id: 11165
Date Added: 27th Apr 2009