ELISA was performed to quantify 1–40 and 1–42 using a multiplex kit from Meso Scale Discovery (MSD, Rockville, MD, USA). Briefly, plates were blocked with diluent 35 for 1h at room temperature. Samples were freshly loaded into the wells and incubated with the secondary antibody 6E10 for 2 hr at room temperature. Finally, plates were washed and 150 ul of read buffer was added before reading using the MSD Sector Imager 2400 (MesoScale Discovery, Rockville, MD).
