Fig. 7.

Hypothetical linear and U-shaped arrangements of CD22. The hypothetical linear arrangement results in the epitope clusters being far apart (A), whereas the hypothetical U-shaped arrangement formed by the C-type domains 1–4 brings the epitope clusters into closer proximity for binding to CAT-8015 and potentially enables cis interactions with sialic acid groups on other cell surface glycoproteins (B). Also shown is a schematic representation of the CD22 fragment (V234–G435) in the context of β-lactamase (C).