LILRB2

Ideogram human chromosome 19

LILRB2 (Leukocyte Immunoglobulin-Like Receptor B2), also known as ILT4 (Immunoglobulin-Like Transcript 4), is a protein that in humans is encoded by the LILRB2 gene. This receptor belongs to the immunoglobulin superfamily and is expressed on the surface of various immune cells, including monocytes, dendritic cells, and certain types of T cells. LILRB2 plays a critical role in the regulation of the immune response, particularly in the modulation of antigen presentation and the maintenance of immune tolerance.

Function

LILRB2 is an inhibitory receptor that recognizes class I Major Histocompatibility Complex (MHC) molecules. Upon binding to its ligands, LILRB2 transmits inhibitory signals that can dampen the immune response. This mechanism is crucial for preventing overactivation of the immune system and for maintaining tolerance to self-antigens, thereby avoiding autoimmune diseases. LILRB2's interaction with MHC class I molecules is also involved in the modulation of antigen presentation to T cells, affecting the immune system's ability to fight infections and cancer.

Clinical Significance

The expression and function of LILRB2 have been implicated in various clinical conditions. In cancer, some tumors exploit the inhibitory pathways mediated by LILRB2 to escape immune surveillance. By expressing ligands for LILRB2, tumors can inhibit the activation of immune cells, promoting tumor growth and metastasis. Therefore, LILRB2 is being studied as a potential target for immunotherapy, with the aim of blocking its interaction with tumor-derived ligands to enhance the immune response against cancer.

In the context of transplantation, LILRB2's role in immune tolerance makes it a target of interest for preventing transplant rejection. Modulating LILRB2's activity could potentially improve the outcomes of organ transplants by reducing the immune system's attack on the transplanted tissue.

Furthermore, the involvement of LILRB2 in autoimmune diseases is under investigation. Given its role in maintaining immune tolerance, therapies aimed at enhancing LILRB2 signaling could offer new avenues for treating conditions characterized by an overactive immune response against self-tissues.

Genetics

The LILRB2 gene is located on chromosome 19 in a cluster with other genes encoding leukocyte immunoglobulin-like receptors. This gene family is highly polymorphic, which may influence the expression and function of LILRB2 in the population.

Research Directions

Research on LILRB2 is focused on elucidating its role in immune regulation and exploring its potential as a therapeutic target. Studies are ongoing to better understand how LILRB2 interacts with its ligands and how these interactions can be modulated to treat diseases. The development of antibodies or small molecules that can specifically target LILRB2-ligand interactions holds promise for enhancing immune responses in cancer, improving tolerance in transplantation, and treating autoimmune diseases.