On the cover: C1q efficiently co-localizes with the therapeutic CD20 Ab ofatumumab bound to Daudi cells. A1647 ofatumumab-opsonized cells (red) were examined for co-localization with bound A1488 C1q (green) by multi-spectral high resolution digital imaging. Light scatter, fluorescence and bright field images, including merged fluorescent (yellow-orange) images are displayed. Pawluczkowycz, A. W., F. J. Beurskens, P. V. Beum, M. A. Lindorfer, J. G. J. van de Winkel, P. W. H. I. Parren, and R. P. Taylor. 2009. Binding of Submaximal C1q promotes complement-dependent cytotoxicity (CDC) of B cells opsonized with anti-CD20 mAbs ofatumumab (OFA) or rituximab (RTX): considerably higher levels of CDC are induced by OFA than by RTX. J. Immunol. 183: 749–758.