Expression And Purification Of Bovine Procalcitonin Protein And Construction Of Single Chain Antibody Expression Vector

Procalcitonin(PCT)is a precursor of calcitonin and con sists of 116 amino acids.In human medicine,it is commonly used as a highly specific early marker of microbial infections and sepsis.In severe systemic inflammation and bacterial infections,plasma concentrations of PCT are significantly elevated within 2-4hours and persist until recovery,so PCT is often used as a marker of sepsis to distinguish bacterial infections and to guide antibiotic therapy.In veterinary medicine,PCT has been less studied and lacks a validated test,so it is not usually used in actual production.In this experiment,we first synthesized the bovine PCT gene artificially and constructed the expression vector of bovine PCT,and expressed and purified the bovine PCT protein using E.coli as the expression system;immunized Balb/c mice with bovine PCT protein as the antigen to construct a bovine PCT-specific phage antibody library,and then enriched the antibody library with prokaryotic expression of bovine PCT protein for 5 rounds of screening,identified bovine PCT protein binding b y Phage ELISA The positive clones were identified by Phage ELISA,the positive clones were extracted from the recombinant plasmids,and then the sc Fv-p MECS recombinant plasmids were double digested and ligated into the p ET-22 b vector.In this experiment,we successfully obtained single-chain antibodies to bovine PCT by applying phage display technology and constructed sc Fv-p ET-22 b recombinant plasmid,which laid the foundation for the subsequent preparation of bovine PCT single-chain antibodies.