Birbeck granule

Birbeck granule is a unique cellular structure, often found in Langerhans cells, which are part of the body's immune system. Named after its discoverer, Michael Stanley Birbeck, these granules are characterized by their distinctive rod or racket shape and are believed to play a crucial role in antigen processing.

Structure

Birbeck granules are typically 33 nm in diameter and can range from 100 to 200 nm in length. They are composed of a central dense core surrounded by a clear zone, and are often seen with a terminal expansion resembling a tennis racket. The granules are primarily composed of a protein called Langerin, which is responsible for their unique structure.

Function

The exact function of Birbeck granules is not fully understood. However, they are believed to play a role in the endocytic pathway, aiding in the internalization and processing of antigens. The presence of Langerin suggests that these granules may also be involved in the formation of Birbeck granule-like structures in non-Langerhans cells.

Clinical significance

Birbeck granules are a diagnostic marker for Langerhans cell histiocytosis, a rare disease characterized by the proliferation of Langerhans cells. The presence of these granules can be confirmed through electron microscopy, aiding in the diagnosis of this condition.

See also

• Langerhans cell
• Langerhans cell histiocytosis
• Antigen processing
• Endocytic pathway