CD20 is a transmembrane protein of the tetra-spanin family expressed on the surface of B-cells and has been found on B-cells from peripheral blood as well as lymphoid tissues. CD20 expression persists from the early pre-B cell stage until the plasma cell differentiation stage. Conversely, it is not found on hematopoietic stem cells, pro-B cells, differentiated plasma cells or non-lymphoid tissues. In addition to expression in normal B-cells, CD20 is expressed in B-cell derived malignancies such as non-Hodgkinâ„¢s lymphoma (NHL) and B-cell chronic lymphocytic leukemia (CLL). CD20 expressing cells are known to play a role in other diseases and disorders, including inflammation. The present invention includes anti-CD20 antibodies, forms and fragments, having superior physical and functional properties immunoconjugates, compositions, diagnostic reagents, methods for inhibiting growth, therapeutic methods, improved antibodies and cell lines and polynucleotides, vectors and genetic constructs encoding same.La presente invención se refiere a un anticuerpo o un fragmento que se une a un antígeno del mismo que se une de manera específica a un CD20, que se caracteriza porque dicho anticuerpo o fragmento, comprende una región variable de cadena liviana y una región variable de cadena pesada, en donde el CDR-L1, CDR-L2 y CDR-L3 de la región variable de cadena liviana comprende las secuencias de aminoácidos con Nos. de ID de SEQ: 17-19, respectivamente, y en donde el CDR-H1, CDR-H2 y CDR-H3 de la región variable de cadena pesada comprende las secuencias de aminoácidos con Nos. de ID de SEQ: 20-22, respectivamente.
