Immunoglobulin M (IgM)

Immunoglobulin M 

Largest immunoglobulin

It constitutes 5-8% of serum.

Ig M is present in intravascular in distribution.

Earliest immunoglobulin to be synthesized in foetus.

It can't cross the placental barrier.

First antibody produced in primary immune response.

Function of IgM

1. Useful in diagnosis of congenital Infection such as;

Syphilis, Rubella, HIV, Toxoplasmosis

2. Presence of IgM in fetus or new born indicates intrauterine infection.

3. Responsible protection against blood invasion by microorganisms.

4. Efficient agglutinating and cytolytic agent

5. Efficient first line of defence incase of bacteriaemia.

6. Participate in complement fixation

7. First antibody produce in primary response