PAX-5 Antibody is a B-cell specific activator protein (BSAP). In early stages of B-cell development, PAX-5 influences the expression of several B-cell specific genes, such as CD19 and CD20. PAX-5 is expressed primarily in pro-, pre-, and mature B-cells, but not in plasma cells. There is an excellent correlation between CD20 and Pax-5 expression; however anti-Pax-5 exceeds the specificity and sensitivity of L26 (CD20) because of its earlier expression in B-cell differentiation and its ability to detect all committed B-cells, including classic Hodgkin’s lymphoma. It is very specific to B-cell lineage and does not stain T-cells. In essence, PAX-5 may be a superior pan B-cell marker to CD20 (see reference).