Preparation of anti-human PD-1 antiserum with high-affinity and its application in PD-1 immunoblotting analysis

The anti-human soluble program death-1(sPD-1) antiserum was prepared by immunizing mice with the purified recombinant sPD-1.Immunoblotting analysis showed that this antiserum had specific reaction with sPD-1,and had some cross-reactivity with bacterial proteins.This cross-reactivity was significantly decreased after treating the antiserum with whole bacterial lysates.PD-1 expressed by activated Jurkat T cells was enriched by affinity chromatography,and assayed by commercial antibody and the antiserum respectively.Only the antiserum identified the natural PD-1,its apparent molecular weight is about 49 000.