CD Antigens

Key Biological Properties: CD2 is a glycoprotein with a molecular weight of 40-60 kDa . It is involved in the activation and adhesion of T cells and NK cells .

Expression Patterns: CD2 is expressed on all peripheral blood T cells, most thymocytes, and some NK cells . It is not found on B lymphocytes .

Tissue Distribution: CD2 is selectively expressed in immune cells and is localized to the plasma membrane . It is also found in the nucleoplasm and Golgi apparatus .

Primary Biological Functions: CD2 is primarily involved in the activation and adhesion of T cells and NK cells . It interacts with other adhesion molecules such as lymphocyte function-associated antigen-3 (LFA-3/CD58) in humans, or CD48 in rodents .

Role in Immune Responses: CD2 acts as a co-stimulatory molecule on T and NK cells, enhancing their activation and proliferation . It plays a significant role in the formation and organization of the immunological synapse, which is crucial for effective immune responses .

Pathogen Recognition: CD2 is involved in the recognition of pathogens by facilitating the interaction between T cells and antigen-presenting cells .

Mechanisms with Other Molecules and Cells: CD2 interacts with LFA-3 (CD58) and CD48 to mediate adhesion between T cells and other cell types . This interaction is vital for the stable formation of the immunological synapse and subsequent T cell activation .

Binding Partners: CD2 binds to LFA-3 (CD58) in humans and CD48 in rodents . These interactions are crucial for T cell activation and adhesion .

Downstream Signaling Cascades: Upon binding to its ligands, CD2 triggers downstream signaling cascades that involve the activation of protein tyrosine kinases such as fyn and lck . These signaling pathways are essential for T cell activation and proliferation .

Regulatory Mechanisms: The expression and activity of CD2 are regulated at multiple levels, including transcriptional regulation and post-translational modifications .

Transcriptional Regulation: CD2 expression is regulated by various transcription factors that bind to its promoter region .

Post-Translational Modifications: CD2 undergoes several post-translational modifications, including glycosylation, which is essential for its proper function and localization .

Biomedical Research: CD2 is widely used as a marker for T cells and NK cells in immunological studies . It is also used to study T cell activation and adhesion mechanisms .

Diagnostic Tools: CD2 is used in immunohistochemistry to identify T cells and NK cells in tissue sections . It is also used to distinguish T cell lymphomas and leukemias from B cell neoplasms .

Therapeutic Strategies: CD2 modulators are being explored as potential therapeutic agents in cancer immunotherapy and autoimmune diseases . CD2 agonists can enhance T cell activation and proliferation, while CD2 antagonists can dampen excessive T cell activity .

Development: CD2 is expressed early in T cell development and plays a crucial role in the positive selection of T cells in the thymus .

Aging: CD2 expression is upregulated on memory T cells and activated T cells, indicating its role in maintaining immune memory throughout life .

Disease: CD2 is implicated in various diseases, including autoimmune disorders and cancers . Its expression and function are often altered in these conditions, making it a potential target for therapeutic interventions .