Immunoglobulin G (IgG), an antibody that participates in the response to infection, could have a specific role in metabolism. During aging, it accumulates in certain tissues inducing metabolic dysfunction and fibrosis of fat tissue. This effect could be prevented through an intracellular receptor that contributes to the delivery of IgG. A team of researchers from Columbia University and Peking University (PKU) demonstrated that reducing excess IgG improved the metabolic health of aged mice and increased their life expectancy.