[Preparation and characterization of monoclonal antibodies against human neuropilin 1 b1b2 domain (HuNRP1b)]

Abstract

Objective To prepare recombinant protein of human neuropilin 1 b1b2 domain (HuNRP1^b) and monoclonal antibodies (mAbs) against the recombinant HuNRP1^b (rHuNRP1^b). Methods The coding sequence of HuNRP1^b was amplified and cloned into vector pET22b to construct recombinant plasmid pET-HuNRP1^b. After analyzed by restriction enzyme digestion and DNA sequencing, pET-HuNRP1^b was transformed into Escherichia coli and induced to express rHuNRP1^b with histidine tag (His-HuNRP1^b), which was identified by SDS-PAGE analysis. Then His-HuNRP1^b was used as immunogen to immune BALB/c mice. After the fusion of spleen cells and Sp2/0 cells, the positive hybridoma cells were screened by indirect ELISA that was established with recombinant HuNRP1^b with a trigger factor tag (TF-HuNRP1^b). The specificity of mAbs against HuNRP1^b was identified by ELISA and Western blotting. The ability of mAbs to bind native HuNRP1 was revealed by indirect fluorescence assay (IFA). Results His-HuNRP1^b was expressed and obtained. Western blotting showed that mAbs 1A10, 6A2 against rHuNRP1^b could bind His-HuNRP1^b with the band of 34 kDa and TF-HuNRP1^b with 89-kDa band, respectively, but not the proteins from bacteria with empty vectors. IFA revealed that the mAbs could bind native HuNRP1 expressed on breast cancer cell line MDA-MB-231. Conclusion The mAbs specific to rHuNRP1^b were generated successfully.