In the making

By Arnab Pratim Dutta
Published: Thursday 30 April 2009

A universal drug to work against all strains of flu virus

influenza vaccine makers are often flummoxed by the changing nature of the virus. The makers need to keep producing new vaccines because the virus keeps mutating into new strains. World Health Organisation estimates that about 250,000 people die from influenza every year. A team of researchers tried to rework the basics of the influenza vaccine.

A vaccine basically contains the antigens from the pathogen it protects against. In some cases, it is the pathogen in a weak or deactivated form. The vaccine activates the body's immune cells which release antigen-specific antibodies, a group of proteins. This alerts the body against the germ and helps the body recognize and neutralize the germ from invading.

The team led by researchers from the Dana-Farber Cancer Institute has used antibodies directly. If they succeed, their work may lead to one-of-a-kind drug which could work against different strains of influenza A viruses including the dreaded H5N1 bird flu virus.

The researchers first identified 10 groups of monoclonal antibodies. These are manmade clones of natural antibodies that are completely identical, produced by the same immune cell. These groups of antibodies have been successful in combating the H5N1 bird flu virus and also the Spanish Influenza virus that was responsible for over 40 million deaths in 1919. The researchers then found out what makes the antibodies so successful against the virus.

The team discovered that the monoclonal antibodies worked by attaching themselves to a section of the virus called the hemagglutin whose shape resembles that of a lollipop. Hemagglutin is the part via which the virus penetrates healthy cells. By attaching themselves to it, the antibodies prevented the virus from entering a cell. When the researchers tested them on mice, they found three of the cultured antibodies neutralized 10 of the 16 known influenza A strains.

According to Wayne Marasco of Dana-Farber Cancer Institute, the antibodies could perform a dual role: one as a vaccine and the other as an antidote to treat people already infected. "It lends itself to a therapy that can be used to prevent and treat a broad range of avian and seasonal influenzas," he said in the study that appeared in an online edition of Nature Structural and Molecular Biology in February 2009.

Influenza raised havoc in the last century. The Spanish flu which struck between 1918 and 1919 killed more than 40 million people. Two other outbreaks known as Asian influenza and Hong Kong influenza had high morbidity rates. In 2002, Madagascar reported 27,000 cases of influenza A infections and death of about 800 people.

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