A study published today in the open access journal Respiratory Research (http://respiratory-research.com) reveals that a dose of 100 µg of horse anti-serum effectively protects infected mice. These results suggest that anti-H5N1 antibodies developed in horses could potentially be used to prevent death from H5N1 influenza, or as early treatment for the disease, in humans.
Jiahai Lu from Sun Yat-Sen University in Guangzhou, China and colleagues from other institutions in China infected dog kidney cells in vitro with a lethal dose of H5N1 and simultaneously exposed the cells to horse antibodies against H5N1. Lu et al.'s results show that horse antibodies to H5N1 protected cells against H5N1 in vitro ?the cells simultaneously infected with H5N1 and exposed to horse antibodies did not die.
Lu et al. then injected horse antibodies into 40 mice that had been infected with a lethal dose of H5N1 24 hours earlier. The authors also injected horse serum without H5N1 antibodies into a group of mice that acted as controls.
The authors found that 50µg of antibody protected 70% of the mice against death by H5N1 and 100 µg of antibody protected 100% of the mice. The mice in the control group died nine hours after receiving the normal horse serum.