Swiss researchers identify universal antibody that eleminates all influenza A virus types
Bellinzona – Using a novel technology, Swiss researchers for the very first time have identified an antibody that targets all of the existing 16 hemagglutinin (HA) epitopes expressed on influenza A viruses and thus provides a universal flu treatment (Science, doi: 10.1126/science.1205669). The immunologists under Antonio Lanziavecchia from the Institute for Research in Biomedicine have filed for two patents (PCT/IB/2009/007375 and PCT/US2009/051851) and in this March founded the company HuMAbs BioMed S.A. to exploit their findings. Using a novel single cell culture method for plasma cells, the researchers screened B cells from 8 patients, who had been infected with different influenza A strains. After having screened more than 100.000 plasma cells they found the FI6 antibody that conferred protection to mice and ferrets from infections with flu viruses independently from which HA type was expressed at its surface. Structural analyses revealed that the antibody acted through binding and stabilisation of a conserved HA epitope in the F subdomain. The new screening technique for such rare antibodies is based on IL-6 supported stabilisation of human plasma cells and subsequent high throughput binding assays. According to Lanziaveccia, the antibody could pave the way for the development of a universal vaccine, which mimicks the effect of F16, against influenza A viruses – the bugs behind swine flu, bird flu and winter flu. According to Lanziavecchia, in humans reduction of the viral load by 10% could help stop people getting sick. Up to now, all major flu outbreaks were causes by viruses belonging to the influenza A class, which show higher variability in their hemagglutinin and neuraminidase surface antigens than influenza B viruses.