Figure 2.

The basic structure and functional components of human immunoglobulin G (IgG). The murine CDR site of a “humanized” antibody is a recombinant product where the CDR site is engrafted to the remaining elements of a human IgG to limit cross species immunogenicity associated with fully murine monoclonal antibodies or a chimeric hybrid antibody consisting of murine VL and VH domains linked to the constant domains of a human antibody. Fab, fragment antibody binding; Fc, crystallizable fragment of immunoglobulin; CDR, complementarity determining regions; Ag, antigen; VL, variable domain of the light chain; VH, variable domain of the heavy chain; CL, constant domain of the light chain; CH1–3, the first through third constant domains of the immunoglobulin heavy chain; N-, asparagine-linked glycosylation site; C’, complement; FcγR, Fc gamma receptors.