Anti-PD-L1 antibody for detecting PD-L1

A method to diagnose cancer and/or infection comprising contacting in vitro one or more cells from a subject with an antibody;

• and
• determining if said antibody binds to said one or more cells,
• wherein increased binding to said cells as compared to a control is indicative of cancer and/or infection,
• wherein the cancer is a cancer where cancer cells express PD-L1,
• wherein the infection is an infection where infected cells express PD-L1, and
• wherein said antibody is an anti-PD-L1 antibody comprising
• (a) a light chain comprising CDR1 having the amino acid sequence of KSISKY (SEQ ID NO:
• 1), CDR2 having the amino acid sequence of SGS and CDR3 having the amino acid sequence of QQHNEYPLT (SEQ ID NO:
• 2) and
• (b) a heavy chain comprising CDR1 having the amino acid sequence of GYTFTDYI (SEQ ID NO:
• 3), CDR2 having the amino acid sequence of INPDSGGN (SEQ ID NO:
• 4) and CDR3 having the amino acid sequence of ARGITMMVVISHWKFDF (SEQ ID NO:
• 5),
• wherein said antibody binds ovine, bovine, porcine or canine PD-L1 proteins, and
• wherein the cancer is not malignant melanoma.