Structure of an immunoglobulin G1 (IgG1) antibody highlighting the key components. The antigen-binding fragment (Fab) arms comprise the antigen-binding regions and consist of the whole light chains and part of the heavy chains. The fragment crystallizable (Fc) region is responsible for the ability of the antibody to be recognized by effectors of immunity. Fc fragments do not recognize the corresponding antigen, but instead bind to various cell receptors (e.g., T-cells) and complement proteins. All antibodies are glycosylated at conserved positions in their constant regions. For example, they possess an N-glycosylation site at the conserved N297 residue of the Fc region. Adapted from ref. 16 with permission from Springer Nature, Copyright 2016.