Plasma Cells in animals
Plasma cells are white blood cells which produce large volumes of antibodies. They are transported by the blood plasma and the lymphatic system and originate from the bone marrow.
They are otherwise known as plasma B cells , plasmocytes , and effector B cells. They are present in lymph nodes ,spleen and diffuse lymphoid tissue of alimentary and respiratory tract.
Structure of Plasma cells
Plasma cells are large lymphocytes round in shape containing a granular cytoplasm which stains with basic dyes.
The nucleus is eccentric in position and typically represents clumps of chromatin in a radiating manner, resembling a “cart -wheel” or clock face in appearance. They have a considerable nucleus-to-cytoplasm ratio.
The cytoplasm contains a conspicuous Golgi apparatus and abundant endoplasmic reticulum Immunoglobulins are localized in the endoplasmic reticulum where it sometimes forms aggregates called as Russel bodies.
Formation of Plasma cells
When specific B-lymphocytes are stimulated by specific antigen, they enlarge and become lymphoblast, some of which further differentiate to immature plasmablasts which finally forms, the plasma cells.
Functions of Plasma Cells
These cells are rarely seen in the circulation, which are formed by the lymphoid tissues (spleen). They play a very important function in body defense mechanism.
They are involved in the production of humoral antibodies. Plasma cells are concerned with the synthesis, storage and release of immunoglobulins at a very rapid rate.
A plasma cell can only synthesize an antibody of a single specimen, either IgM or IgG or IgA except in primary immune response when a plasma cell producing IgM initially, may later switch over to the synthesis of IgG antibody. Mature plasma cells are end cells and survive only a few weeks and die after a few cell division.