Chinese scientists have produced antibodies in horses that are an effective treatment for bird flu – at least in mice.
Jiahai Lu at Sun Yat-sen University in Guangzhou and colleagues repeatedly inoculated horses with a chicken vaccine against H5N1 bird flu to make them produce antibodies.
They then collected the horses’ blood, separated out the antibodies and split them to make them less likely to cause an allergic reaction when injected into a human. When they injected mice with a tenth of a milligram of these antibodies 24 hours after they had been given an otherwise lethal dose of H5N1, all the mice lived.
In theory, such antibodies could be made quickly against a pandemic strain of H5N1, potentially saving many lives and limiting the spread of the virus. The trouble is that most drug companies have stopped making antibodies this way.
This is because keeping horses is expensive and until now the markets for antiserum have been in poor countries and offer low financial returns. In addition, animal rights campaigners object to the technique.
Companies have instead invested in making modern, monoclonal antibodies using cell cultures. "It would be complex and expensive for a company to hugely scale up its monoclonal production to treat whole populations rather than a few people,” says David Fedson, founder of the vaccine industry’s pandemic task force.