Preparation And Identification Of Specific Single Domain Antibody For B-cell Maturation Antigen

B-cell maturation antigen(BCMA)is a protein specifically expressed on the surface of multiple myeloma(MM)cells and plasma cells.The targeted single domain antibody(sdAb)can specifically bind to the BCMA protein on the surface of MM cells;sdAb is high water solubility,low immunogenicity,strong tissue penetration and strong stability.Will play a role in the specific immunoassay and treatment of MM.In this experiment,BCMA protein was used to immunize bactrian camel,and the variable domain of the heavy chain of HCAb(VHH)gene pool was obtained.The gene bank was transformed into E.coli TGI strain,and the phage antibody library was constructed for three rounds of enrichment and panning.The BCMA protein identified by Phage ELISA was selected.Highly bound recombinant phage.The VHH gene was cloned into the prokaryotic expression vector pET-25b-SBP,and soluble expression was carried out by low temperature induced engineering bacteria,and the supernatant was purified by nickel column to obtain soluble BCMA-specific sdAb.The ELISA was carried out to identify its affinity activity,and the following conclusions were obtained:(l)After immunization,the serum antibody titer was 1:16000,and the BCMA-specific phage antibody library was 3.15 ×106.Detection of 52 positive recombinant phage by phage ELISA after screening.(2)The VHH gene was cloned into the prokaryotic expression vector pET-25b-SBP,and the colony PCR and expression were identified for high expression screening.The engineering bacteria were induced a to obtain soluble BCMA-specific sdAb;ELISA assay identified sdAb and BCMA neutralized reaction,and has affinity activity.