Description: This 24C2.5 monoclonal antibody reacts with the intracellular tail of mouse CD79a (also known as Ig alpha or mb-1), a signaling component of the B cell receptor (BCR). CD79a heterodimerizes with CD79b (Ig beta, B29), and together with surface Ig, make up the BCR. Both CD79 subunits consist of a single extracellular Ig domain, a transmembrane domain, and an intracellular signaling domain. CD79a is expressed almost exclusively on B cells, as well as in most B lineage acute lymphoblastic leukemias. The cytoplasmic domain of CD79a contains immunoreceptor tyrosine-based activation motifs (ITAMs), which constitute the signal transducing portions of the BCR. Tyrosine phosphorylation of these ITAMs by Syk and Lyn initiates numerous signaling cascades, resulting in B cell activation, proliferation, and differentiation.