what does igg do?
IgM vs IgG. An immunoglobulin or antibody refers to proteins that bind to antigens in specific cases. Both IgM and IgG refer to a class of immunoglobulin. Antibodies are produced by the immune system to fight antigens like bacteria and viruses. IgM refers to those antibodies that are produced immediately after an exposure to the disease, while IgG refers to a later response.