Programmed death ligand-1 (PD-L1, CD274 and B7-H1) has been
described as a ligand for immune inhibitory receptor programmed death
protein 1 (PD-1). With binding to PD-1 on activated T cells, PD-L1 can
prevent T cell responses via motivating apoptosis. Consequently, it
causes cancers immune evasion and helps the tumor growth; hence, PD-L1
is regarded as a therapeutic target for malignant cancers. The
anti-PD-L1 monoclonal antibody targeting PD-1/PD-L1 immune checkpoint
has attained remarkable outcomes in clinical application and has turned
to one of the most prevalent anti-cancer drugs. The present study aimed
to develop polyclonal heavy chain antibodies targeting PD-L1via Camelus dromedarius
immunization. The extra-cellular domain of human PD-L1 (hPD-L1) protein
was cloned, expressed, and purified. Afterwards, this recombinant
protein was utilized as an antigen for camel immunization to acquire
polyclonal camelid sera versus this protein. Our outcomes showed that
hPD-L1 protein was effectively expressed in the prokaryotic system. The
antibody-based techniques, such as enzyme-linked immunosorbent assay,
western blotting, and flow cytometry displayed that the hPD-L1 protein
was detected by generated polyclonal antibody. Due to the advantages of
multi-epitope-binding ability, our study exhibited that camelid antibody
is effective to be applied significantly for detection of PD-L1 protein
in essential antibody-based studies.