The 53-2.1 monoclonal antibody reacts with mouse CD90.2 (Thy-1.2), an ~25 - 35 kDa glycophosphatidylinositol (GPI)-anchored glycoprotein expressed at high levels on the surface of thymocytes, most peripheral T cells and lymphatic endothelial cells, and at lower levels on hematopoietic stem cells, some intraepithelial T lymphocytes, fibroblasts and neurons. CD90.2 is an allelic form of the CD90 antigen expressed by mouse strains BALB/c, C3H/He, C57BL/6, C58/, CBA/J, DBA, NZB/-, SJL and others. The 53-2.1 antibody does not react with CD90.1, which is expressed by mouse strains such as AKR/J, PL, and FVB/N, or with rat CD90. CD90.2 has been shown to be involved in costimulation of lymphocyte proliferation, as well as in hematopoietic stem cell differentiation and thymocyte adhesion. The 53-2.1 antibody reportedly blocks the binding of antibody clone 30-H12.
