Used in research and development of immunotherapies targeting T cells, particularly in the context of autoimmune diseases and transplant rejection. Binds specifically to the CD2 receptor on T cells, modulating immune responses by interfering with T-cell activation and adhesion. Investigated in clinical settings to deplete or regulate T-cell activity, especially in hematopoietic stem cell transplantation to prevent graft-versus-host disease. Also serves as a reference standard in bioassays and antibody characterization studies due to its well-defined specificity and function.