Clone REAL133 is an antibody fragment derived from the full CD49b antibody molecule. It displays no binding to Fc receptors. The recombinantly engineered antibody fragments are multimerized to form the REAlease Complex to bind markers with high avidity.

Clone REAL133 recognizes the mouse CD49b antigen, a single-pass type I membrane protein also known as integrin alpha-2 (ITGA2). CD49b together with CD29 (ITGB1) forms the adhesion molecule very late antigen-2 (VLA-2), which binds mainly to collagens I, II, and XI. VLA-2 is responsible for adhesion of platelets and other cells to collagens, modulation of collagen and collagenase gene expression, force generation, and organization of newly synthesized extracellular matrix. It is also a receptor for laminins, collagen C-propeptides, and E-cadherin. Mice homozygous for a null mutation in the CD49b gene die very early in embryogenesis. CD49b is expressed on the vast majority of mouse natural killer (NK) cells and on a subset of NKT cells. It is not as mouse strain-restricted as other NK cell markers, for example, NK1.1, and is expressed by most common inbred mouse strains. Bone marrow (BM) resident memory T helper (Tʜ) cells also express CD49b and the homing of adoptively transferred bone marrow (BM) memory Tʜ cells to BM can be efficiently blocked by antibodies to CD49b. This points to a decisive role of CD49b in the trafficking of memory Th cell precursors to the BM niches for memory Tʜ cells.

The REAlease Kits consist of the respective fluorochrome-conjugated REAlease Complexes and the REAlease Support Kit for removal of the REAlease Complexes and optional relabeling with different fluorochrome-conjugated REAlease Complexes.