The immune system ages in a variety of ways. It might be considered several overlapping systems that all interact closely with one another, while each component has its own distinct forms of dysfunction that arise in later life. Researchers here report on their investigation of aging in B cells, responsible for the generation of antibodies. They link aging to altered expression of genes related to IGF-1, an area of biochemistry long known to be influential in determining the pace of aging in mammals. Like most such well known aging-related regions of mammalian biochemistry, this touches on stress response and nutrient sensing, and is involved in the mechanisms by which calorie restriction extends life span.
Antibodies are generated in specialized cells called B cells. The pathway that generates these cells is highly complex, encompassing many precursor cell types. All of the early steps of this process occur in the bone marrow where dedicated precursor B cells are generated from hematopoietic stem cells. The aging process strongly impacts these early steps, with reduced numbers of precursor B cells and a decline in the developmental flow of these cells towards mature B cells that secrete antibodies. Importantly, this reduces