The present inventors discovered that antibodies having weaker antigen-binding activity at the early endosomal pH in comparison with that at the pH of plasma are capable of binding to multiple antigen molecules with a single antibody molecule, have long half-lives in plasma, and have improved durations of time in which they can bind to antigen. Various embodiments of the present invention include a cartridge body that movably supports first and second staple drivers. Each font may comprise a plurality of font images and a font image may be retrieved for each character of the reference data. Each drive wheel is operably coupled to a drive motor. Coupling structure allows the optics body to be selectively coupled to the mounting base such that a flange on the optics body is selectively aligned with the mounting base when in an engaged position. The shaft in turn has a primary thread for engaging a first part and a secondary thread for engaging a second part, wherein the primary thread and the secondary thread have different pitches.