LAG-3/PD-1 Antibodies

Target Information

LAG-3 is a 70-kDa surface glycoprotein in the immunoglobulin superfamily, with structural homology to CD4. It binds to MHC class II molecules with higher affinity than CD4 and is involved in the negative regulation of T cell activation and homeostatic proliferation. LAG-3 is expressed on the surface of activated T cells, including regulatory T cells, and NK cells. Notably, CD8+ T cells express LAG-3 at significantly higher levels than CD4+ T cells. Additionally, the coexpression of LAG-3 and CD49b has been proposed as a marker for identifying Type 1 regulatory T cells (Tr1 cells) in both humans and mice. This highlights LAG-3s role in immune regulation and its potential as a target for therapeutic interventions in immune-related conditions.

Cell-mediated immune responses are initiated by T lymphocytes that are themselves stimulated by cognate peptides bound to MHC molecules on antig en-presenting cells (APC). T-cell activation is generally self-limited as activated T cells express receptors such as PD-1 (also known as PDCD-1) that mediate inhibitory signals from the APC. PD-1 can bind two different but related ligands, PDL-1 and PDL-2. Upon binding to either of these ligands, signals generated by PD-1 inhibit the activation of the immune response in the absence of "danger signals" such as LPS or other molecules associated with bacteria or other pathogens. Evidence for this is seen in PD1-null mice who exhibit hyperactivated immune systems and autoimmune diseases. Despite its predicted molecular weight, PD-1 often migrates at higher molecular weight in SDS-PAGE.