Microfold cell

Microfold cells (also known as M cells) are specialized epithelial cells that can be found in the gut-associated lymphoid tissue (GALT) of the digestive system. They play a crucial role in the immune response by transporting antigens from the gut lumen to immune cells in the underlying lymphoid tissue.

Structure

Microfold cells are found in the follicle-associated epithelium (FAE) of Peyer's patches, isolated lymphoid follicles, and mesenteric lymph nodes. They are characterized by a unique microfold or ruffled surface, which increases their surface area and enhances their ability to capture antigens.

Function

The primary function of M cells is to transport antigens from the gut lumen to the underlying lymphoid tissue. This process, known as transcytosis, involves the uptake of antigens by endocytosis, their transport across the cell, and their release on the other side by exocytosis. Once the antigens are released, they are taken up by dendritic cells and macrophages, which then present them to T cells and B cells to initiate an immune response.

Clinical significance

Due to their role in antigen transport, M cells are a key target for vaccine development. By delivering antigens directly to M cells, vaccines can stimulate a strong and specific immune response. However, M cells can also be exploited by pathogens, such as bacteria, viruses, and prions, to gain entry into the body.

See also

• Peyer's patches
• Gut-associated lymphoid tissue
• Antigen-presenting cell