Immunology researchers have made an important discovery of how antibodies interact with the flu virus which could lead to more effective vaccines. The study found that Immunoglobulin A (IgA) antibodies have a two-pronged method of attacking the flu virus and that the IgA1 subtype, specifically, is a particular skillful at combating the virus. The paper describing the University of Zurich study was published in Cell Reports.
Current flu vaccines are designed with Immunoglobulin G (IgG) and have to be administered yearly. The team studied how influenza A virus interacts with all types of antibodies using in vitro experiments. They found that IgA1 has a unique C-terminal sialic acid tail that blocks the virus from binding and infecting other cells. This finding indicates that IgA subtypes utilize an innate line of defense against the flu virus and other viral pathogens. They also provide protection through traditional acquired immunity where the antibody recognizes specific pathogens which gives the antibody two separate mechanisms to fight infection. The study also showed that IgA exhibited antiviral properties even when there was no classical antibody binding via antigen binding sites.
IgAs are known to be difficult to work with so the research team suggests future research should focus on making production easier and generating antibodies that can be tested in mice. The leader of the study, Lars Hangartner, proposes engineering an IgG-type antibody with the sialic acid tail of an IgA1 antibody making it much easier to work with. "It would combine the best of both worlds and give us a molecule that's more effective and hardy, and that ultimately may be very useful when it comes to fighting the flu," adds the immunologist. Thanks to the strength with which the antibodies attach themselves to the virus, even small amounts would be enough to provide effective protection.
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