{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Lymphocyte-activation gene 3, also known as LAG-3 and designated as CD223, is a cell surface protein with diverse biologic effects on T cell function. The gene for LAG-3 lies adjacent to the gene for CD4 on human chromosome 12 (12p13) and is approximately 20% identical to the CD4 gene. LAG-3 is expressed on activated T cells, natural killer cells, B cells and plasmacytoid dendritic cells. The LAG-3 protein negatively regulates cellular proliferation, activation, and homeostasis of T cells, in a similar fashion to CTLA-4 and PD-1 and has been reported to play a role in the suppressive function of regulatory T cells (Treg). LAG-3 also helps maintain CD8+ T cells in a tolerogenic state and, working with PD-1, helps maintain CD8 exhaustion during chronic viral infection. LAG-3 is known to be involved in the maturation and activation of dendritic cells."}]}]}