Objective        To prepare and characterize the monoclonal antibodies (mAbs) against human procalcitonin (PCT).       Methods        Human PCT protein was expressed with prokaryotic expression system

and the purified recombinant PCT was applied as the antigen for screening the mAbs. Based on bioinformatics analysis

the potential B cell epitopes within human PCT were predicted and synthesized. BALB/c mice were immunized using the synthesized peptides

which were conjuga

ted with bovine serum albumin. Enzyme-linked immunosorbent assay (ELISA)

Western blotting and immunohistochemistry were employed to characterize the mAbs

and the ELISA system that can detect PCT in serum was established.       Results        The PCT recombinant protein was successfully highly expressed and the purity of the recombinant PCT reached about 95% after purification. Three hybridoma cell lines secreting antibodies against PCT

2-D7

2-H12 and 4-H12 were obtained. The subtypes of the mAbs belonged to IgG1 and IgG2a. The monoclonal antibody 2-D7 has the highest titer of 1∶1 024 000 and affinity constant of 1.3×10

9

L/mol. Western blotting showed that 2-D7 only reacted with recombinant PCT and the native PCT in human thyroid gland tissues

but not with unrelated protein H-FABP. Using 2-D7 and the purchased antibody as capturing and detecting antibody

respectively

an ELISA system measuring recombinant PCT was developed. The ELISA system was applied to detect PCT in clinical samples

and significant difference was found between the two groups.       Conclusion        Three monoclonal antibodies against human PCT with high titer and specificity have been successfully prepared

and an ELSIA system for detecting human PCT has been developed

which can be preliminarily used for clinical detection of PCT.