Understanding CD223’s Role in Immune Modulation CD223, also referred to as Lymphocyte Activation Gene-3 (LAG-3), is a pivotal immune checkpoint protein that regulates T-cell activation and maintains immune balance. Present on activated T cells, natural killer cells, B cells, and dendritic cells, CD223 functions similarly to PD-1 and CTLA-4, suppressing immune responses. Its upregulation...