Describe the IgA class of immunoglobulins.

Immunoglobulins:

1. Immunoglobulins are molecules of glycoprotein which is produced by plasma cells.
2. They have an important role in immune response as they recognize and bind to specific antigens and help in destroying them.
3. Immunoglobulins are also known as antibodies.

Immunoglobulin A (IgA):

1. The IgA provides the first line of defense to resist infection.
2. It inhibits viral and bacterial adhesion to epithelial cells and neutralizes bacterial toxins and viruses.
3. It is known to eliminate antigens or pathogens by IgA-mediated excretory pathway.
4. IgA can be oligomeric and comprise two to four IgA monomers.
5. IgA like other antibodies comprises two light and two heavy chains.
6. IgA in serum is ninety percent IgA1 and ten percent IgA2.
7. The dimeric form of IgA is the most prominent and is known as secretory IgA (sIgA).
8. IgA is found in mucous secretions, such as saliva, tears, and sweat.
9. IgA activates the complement system poorly and exhibits weak opsonization.