A B cell produces functional antibodies (green) that lack light chains.
In mammalian antibodies, two heavy chains link together to form a Y-shaped complex, with each arm of the Y linked to a light chain. In mice and humans, lone heavy chains are usually prevented from being secreted by a chaperone that associates with the heavy chain's constant region—the same region that links to the light chain. But the new report shows that an unusual set of fully functional heavy chain–only antibodies do get secreted.
The anomalous antibodies escaped to the cell surface because they lacked the chaperone-binding region. The secretion of these antibodies was discovered in mutant mice that lack light chain genes, but the authors also found that smaller amounts were produced in the spleen of normal...
