Igm and IgG antibodies

Antibodies (immunoglobulins) are complex protein molecules that are produced by the immune system against various antigens. Antigens are usually protein molecules (or associated with proteins) that provoke the immune system’s response. Antibodies are created by the plasma cells that origin from B-lymphocytes. Each antibody binds to precisely determined antigens (specific binding). In normal occasions antigens are foreign things that the immune system tends to remove from the body.


There are 5 classes of immunoglobulins (Ig) or antibodies:

4. IgM – it is a class of antibody that is created first when immune response begins. When it fights an infection for the first time, the immune system needs time to start creating antibodies (seroconversion). First created antibodies are from the IgM-class. Then occurs “switching” and IgM-antibodies are replaced with IgG-class antibodies in a few weeks. Presence of IgM-antibodies in the blood is a mark of the acute phase of an infection. In certain types of immune response, IgM are not replaced with IgG (antibodies against the blood antigens from ABO- blood system remains IgM).
5. IgG – is the major antibody class. In the immune responses to various infections, IgG-antibodies replace the IgM-antibodies after a few weeks. Presence of some IgG-antibodies could be a sign of the chronic phase of an infection, a sign of passed infection, or a sign of successful vaccination. IgG-antibodies can persist for many years in the blood. When the same infection occurs later IgG-antibodies will be created much faster than the first time, without creating IgM-antibodies.