MH 016 Simple Epithelia

Plasma Cells

Plasma cells are derived from B-lymphocytes and produce large quantities of antibodies. They are abundant wherever antigens may enter the body, such as the gastrointestinal tract and the respiratory system.

Many plasma cells are found in the connective tissue of the small intestine underneath the epithelium of villi.

Plasma cells have these characteristics:

• Round to oval shape
• Eccentric nucleus with peripherally dispersed heterochromatin ("clock-face" pattern)
• Slightly basophilic cytoplasm (blue-grey) due to high content of rough endoplasmic reticulum
• Acidophilic area (pink) next to the nucleus occupied by the Golgi Apparatus

The most common cell type within the villi are plasma cells. The arrow points out some of the better examples.

Plasma cells can also be seen in bone marrow.

Plasma cells in connective tissue can be identified by their abundant, rough endoplasmic reticulum (dilated with newly synthesized antibodies), prominent Golgi apparatus, and the absence of secretion granules by transmission electron microscopy. See EM 105 Plasma Cells and EM 114 Plasma Cell.