definiens: means a polypeptide that Targets an antigen, whic h polypeptide comprises : ( a ) one or more immunoglobulin variable domains ; or ( b ) fragments, variants, modifications or derivatives o f such immunoglobulin variable domains irrespective of ori gin or source, including but not limited to antigen binding portions including Fab, Fab ’, F(ab’)2, Fv, dAb and CDR fragments, single chain antibodies ( scFv ), chim eric antibodies, monospecific antibodies, bispecific ant ibodies, multi- specific antibodies, diabodies and other polypep tides, any of which contain at least a portion of a n immunoglobulin that is sufficient to confer speci fic antigen binding to the polypeptide ; and ( c ) in each case ( a ) and ( b ) above, humanized or fully human versions thereof