Describe the characteristics of Immunoglobulins.

Immunoglobulins:
These are group of proteins produced by plasma cells and B-lymphocytes that bind to antigen.

IgG:

1. Most common
2. Subdivided in four subclasses IgG1, IgG2, IgG3, IgG4.
3. Produced 2nd to IgM and sustain
4. Heavy chain gamma
5. Present in serum and extracellular fluid
6. Cross placenta
7. Can be broken into a constant Fc fragment and two highly variable Fab fragments.

IgM:

1. Produced first in response to antigen
2. Heavy Chain is meu
3. Consists of 5 subunit
4. Does not cross placenta
5. Present in serum only
6. Complement fixation usual and very different

IgA:

1. Main Immunoglobulins in secretions
2. Does not cross placenta.
3. Heavy chain alpha
4. Compliment fixation in alternative pathway

IgD & IgE:

1. Involved in delayed hypersensitivity reaction