Immunoglobulin G1, anti-[Homo sapiens CD20 (membrane-spanning 4-domains subfamily A member 1, MS4A1, B lymphocyte surface antigen B1, Leu-16, Bp35)], humanized monoclonal antibody, GA 101; gamma1 heavy chain (1-448) [humanized VH (Homo sapiens FR/Mus musculus CDR, Homo sapiens IGHJ4*01) [8.8.12] (1-119) -Homo sapiens IGHG1*01 (120-448)], (222-219'')-disulfide with kappa light chain (1''-219'') [humanized V-KAPPA (Homo sapiens FR/Mus musculus CDR, Homo sapiens IGKJ4*01)[11.3.9] (1*-112*) -Homo sapiens IGKC*01 (113''-219'')]; (228-228":231-231")-bisdisulfide dimer