BTLA

BTLA or B and T Lymphocyte Attenuator is a protein that in humans is encoded by the BTLA gene. BTLA is a member of the immunoglobulin superfamily and is expressed on T-lymphocytes, B-lymphocytes, and other immune cells. It functions as an immune checkpoint and plays a crucial role in the regulation of immune responses.

Structure

BTLA is a type I transmembrane protein with an extracellular immunoglobulin domain. The extracellular domain of BTLA interacts with its ligand, herpesvirus entry mediator (HVEM), a member of the tumor necrosis factor receptor superfamily.

Function

BTLA serves as a negative regulator of the immune response. Upon binding to HVEM, BTLA inhibits T-cell activation, proliferation, and cytokine production, thereby preventing excessive immune responses and maintaining immune homeostasis. BTLA also plays a role in the development and function of regulatory T cells, which further contributes to immune regulation.

Clinical significance

Alterations in the BTLA-HVEM pathway have been implicated in various diseases, including autoimmune diseases, infectious diseases, and cancer. In cancer, BTLA is often upregulated on tumor-infiltrating lymphocytes, and its interaction with HVEM can contribute to immune evasion by the tumor. Therefore, targeting the BTLA-HVEM pathway is being explored as a potential strategy for cancer immunotherapy.

See also

• Immune checkpoint
• Tumor necrosis factor receptor
• Regulatory T cell