CD Antigens

Key Biological Properties: CD244 is a cell surface receptor expressed on natural killer (NK) cells, T cells, monocytes, eosinophils, myeloid-derived suppressor cells, and dendritic cells . It primarily binds to its ligand CD48, another member of the SLAM family .

Expression Patterns and Tissue Distribution: CD244 is expressed in various hematopoietic cells, including NK cells, T cells, monocytes, basophils, eosinophils, mast cells, and dendritic cells . It is highly expressed in granulocytes, monocytes, blood, testicles, spleen, bone marrow, lymph nodes, and the liver .

Primary Biological Functions: CD244 plays a crucial role in the regulation of the immune system. It provides stimulatory or inhibitory signals that regulate various immune responses, such as cytotoxicity, cytokine production, and intercellular interactions .

Role in Immune Responses and Pathogen Recognition: CD244 is involved in the activation and differentiation of a wide variety of immune cells, thus playing a significant role in both innate and adaptive immune responses . It is essential for the expansion and activation of NK cells and the regulation of immune responses in CD8+ T cells .

Mechanisms with Other Molecules and Cells: CD244 primarily binds to CD48 on adjacent cells, transmitting stimulatory or inhibitory signals that regulate immune function . It can also bind to other low-affinity ligands such as CD229 .

Binding Partners and Downstream Signaling Cascades: The interaction between CD244 and CD48 involves both trans and cis interactions. The intracellular domain of CD244 contains immunoreceptor tyrosine-based switch motifs (ITSMs) that interact with SH2 domain-containing proteins, such as SAP and EAT-2, which are involved in downstream signaling .

Regulatory Mechanisms Controlling Expression and Activity: The expression and activity of CD244 are regulated by various mechanisms, including transcriptional regulation and post-translational modifications . The presence or absence of small cytoplasmic adapter proteins, such as SH2D1A/SAP and SH2D1B/EAT-2, also controls its activities .

Transcriptional Regulation and Post-Translational Modifications: CD244 expression is regulated at the transcriptional level, and its activity can be modulated by post-translational modifications, such as phosphorylation .

Biomedical Research: CD244 is a valuable target in biomedical research due to its role in immune regulation and its involvement in various immune-related diseases, such as autoimmune diseases, infectious diseases, and cancers .

Diagnostic Tools and Therapeutic Strategies: CD244 can be used as a diagnostic and prognostic marker for various diseases. It also holds potential as a therapeutic target for immunotherapy, particularly in the treatment of tumors .

Role Throughout the Life Cycle: CD244 plays a role throughout the life cycle, from development to aging and disease. It is involved in the regulation of immune responses during development and continues to play a crucial role in maintaining immune homeostasis throughout life .

From Development to Aging and Disease: Abnormal interactions between immune cells involving CD244 contribute to the onset and progression of autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and type 1 diabetes (T1D) .