Cluster of differentiation 24 (CD24) (CD24)

Cluster of differentiation 24 (CD24), also known as heat-stable antigen, is a cell surface glycoprotein that functions as a costimulatory molecule and cell adhesion molecule in immune regulation. The protein consists of a small 27-amino acid protein core with extensive glycosylation, and is expressed by hematopoietic cells, B lymphocytes, and activated T lymphocytes[1][5]. CD24 provides CD28-independent costimulation for T cell activation and clonal expansion, serving as a critical checkpoint in both normal immune responses and autoimmune disease development[5]. The molecule is particularly significant in autoimmune neurological diseases, where it has been identified as a therapeutic target; blocking CD24 interactions through soluble fusion proteins can ameliorate disease even after autoreactive T cells have been primed[5]. CD24 represents an attractive therapeutic target for autoimmune conditions because it acts as a checkpoint molecule distinct from classical costimulatory pathways, offering a novel approach for immune intervention in diseases such as multiple sclerosis[5].

Other names

Heat-stable antigen (HSA)NectadrinSignal transducer CD24

CD24 operates as a costimulatory checkpoint molecule. Research indicates that HSA provides CD28-independent costimulation for clonal expansion of T cells. Notably, studies demonstrate that both T cells and non-T cells must express HSA for pathogenic T cells to execute their effector function in autoimmune disease models. A fusion protein (HSAIg) consisting of the extracellular domain of HSA and the Fc portion of immunoglobulin can block HSA-mediated interactions and drastically ameliorate disease signs even after self-reactive T cells have been expanded and activated.