Three different antigen-binding possibilities on the surface membrane of a follicular lymphoma B cell and their anticipated functional consequences are shown. On the far left is the expected scenario. In the absence of an N-linked glycan, an (auto)antigen can interact with the antigen-binding site of the expressed smIg and, with the involvement of the CD79a/d complex (⁠⁠), transduce a downstream BCR-mediated signal. In the middle is the setting in which a high-mannose-terminated glycan in the antigen-binding site (⁠⁠) inhibits the binding of an (auto)antigen, due to either a conformational change in the antigen-binding site or steric hindrance based on the bulk of the glycan. In this instance, a BCR-mediated signal cannot be initiated. Finally, on the right is the situation in which either soluble or organism-bound mannose lectin (⁠⁠) interacts with high-mannose glycan in the antigen-binding site and induces a BCR signal. In the study by Schneider et al, these possibilities have been tested using monoclonal antibodies of defined specificity (before or after insertion of a high-mannose-terminated, N-linked glycan) or Igs derived from FL patients that contain in vivo SHM-induced high-mannose-terminated, N-linked glycans.