The immune system’s capacity to distinguish self from non-self is in large part mediated by immunoglobulins, with IgG playing a pivotal role in both protective and pathological responses.

FcRn protects IgG and albumin from catabolism, transports IgG across the placenta, and regulates IgG function. Blocking or augmenting FcRn can decrease autoimmune antibodies and enhance drug delivery.