An investigator attempted to use fluorescent-labeled F(ab′)2 fragments to locate class II MHC molecules on the cell surface of APCs but did not want to activate the cells or promote the “capping” that...

An investigator attempted to use fluorescent-labeled F(ab′)2 fragments to locate class II MHC molecules on the cell surface of APCs but did not want to activate the cells or promote the “capping” that would occur with cross-linking (binding two molecules together) of these cell-surface molecules.