Calibrator 32 is a lyophilized blend of BTLA, CD80/B7-1, IDO-1, and proMMP-10. It is intended for use as an assay calibrator for MSD U-PLEX human assays that measure any of the included proteins. The utility of this product has not been evaluated in other applications. Individual analyte concentrations are provided in the lot-specific certificates of analysis. BTLA is a recombinant protein expressed in human cells; CD80/B7-1 and proMMP-10 are recombinant proteins expressed in mouse cells lines; IDO-1 was expressed in wheat germ. Instructions on using Calibrator 32 are provided in U-PLEX Immuno-Oncology Group 1 Human Product Inserts.