Effective preventive drug against bird flu developed in the mouse

In a study published today in the open access journal Respiratory Research (http://respiratory-research.com/), researchers have created antibodies against the avian flu virus H5N1 that work in mice both as a preventive drug, or prophylaxis, when administered before infection, and as a treatment for bird flu. These antibodies are part human, part mouse antibodies and would be less likely to be rejected by the human immune system than pure mouse antibodies.

Brendon Hanson and colleagues from the DSO National Laboratories in Singapore, in collaboration with Richard Webby and colleagues from St Jude Children’s Research Hospital in Memphis, USA created two different antibodies able to recognise slightly different types of H5N1 viruses. The antibodies were ‘humanised’ mouse antibodies – they comprised both human and mouse antibody fragments. The antibodies were injected into mice 24 hours before the mice received a potentially lethal dose of H5N1. Other groups of mice were injected with the antibodies one day or three days after receiving the lethal dose of H5N1.

Hanson et al.’s results show that prophylactic use of a low dose (1mg/kg) of the first antibody completely protects the mice from disease and death caused by H5N1. Higher doses are necessary to completely protect the mice from disease and death when administered one (5mg/kg) or three (10mg/kg) days after infection. The second antibody is less effective and only protects the mice from disease when given at a high dose (5mg/kg) 24 hours before infection.