Human PD-L1/CD274 ELISA Kit

Assay Genie offers a Sandwich ELISA, Double Antibody kit designed for the precise measurement of PD-L1 (also known as CD274) in human samples including serum, plasma, cell culture supernatants, cell or tissue lysates, and other liquid samples. PD-L1/CD274 is a key immune checkpoint protein that regulates the immune response and maintains immune tolerance, with abnormal expression linked to cancer, autoimmune disorders, and infectious diseases.

The assay provides a sensitivity of 3.75 pg/mL, a standard range of 6.25-400 pg/mL, and uses colorimetric detection read at 450 nm. Recovery ranges are 87-104% for serum (average 94%), 86-97% for EDTA plasma (average 91%), and 88-104% for heparin plasma (average 96%), all with n = 5. Linearity at dilutions 1:2, 1:4 and 1:8 is 89-96%, 90-103% and 94-105% for serum; 87-101%, 87-93% and 91-99% for EDTA plasma; and 81-98%, 81-100% and 91-97% for heparin plasma (all n = 5). Reagents are stored at 2-8°C with stability for 12 months.

The protocol equilibrates reagents to room temperature, incubates the plate at 37°C for 90 minutes for antigen binding, adds biotin-labelled detection antibody for 60 minutes, then HRP-Streptavidin (SABC) for 30 minutes, develops with TMB substrate in the dark for 10–20 minutes, and reads absorbance at 450 nm after stop solution. Sample preparation includes clotting and centrifugation at 1000 × g for 20 minutes for serum; anticoagulant collection and centrifugation at 1000 × g for 15 minutes at 2–8°C for plasma; homogenisation in PBS with protease inhibitors for tissue; centrifugation at 2500 rpm for 5 minutes for cell culture supernatant; and lysis buffer with protease inhibitors for cell lysates.