Which of the following immunoglobulins increased in primary bacterial infections is

B. i.e. (IgM) (89- Ananthanarayan 7th)* IgM is the first immunoglobulins synthesized in the antibody response (Primary response) and its presence in the serum indicates recent infections. Since it cannot cross the placenta, presence of IgM antibody in serum of foetus or new born indicates intrauterine infections. IgM is also a major component of rheumatoid factor (auto antibodies)**, primary biliary cirrhosis.**A single immunoglobulin is - 2 light chain, 2 heavy chain** IgA increased in respiratory & GIT infections* The most avidly complement fixing antibody is - IgM** (Opsonization)