SSP-SAP eliminates cells expressing the Substance P (NK-1) receptor. All other cells are left untouched, even when they are the predominant cell type. This specific analog of SP-saporin resists peptidase digestion, allowing a greater diffusion from the injection site before its metabolism. Not suitable for retrograde transport. . This kit includes SSP-SAP (Cat. #IT-11) plus Blank-SAP (Cat. #IT-21)