CONFORMATIONAL DIFFERENCES IN 2 MUTANT HINGE IGG4 ANTIBODIES OBSERVEDBY SCANNING-TUNNELING-MICROSCOPY

Images have been obtained of two types of chimeric B72.3 anti-TAG-72 m utant hinge IgG4 antibodies using scanning tunneling microscopy. The a ntibodies were specifically engineered to show differences in their co nformation due to site specific modifications in their hinge regions. To overcome initial difficulties due to tip sweeping effects, the meth od of immobilization employed was spray deposition on mica followed by rotary shadowing with platinum/carbon (Pt/C). Topographic data were o btained, and differences between the two mutant forms of the antibody were clearly visible.