Aim: To screen human anti-gamma-sm (gamma-seminoprotein) light chain (Lc) with guided selection of murine Fd fragment.
Methods: The human Lc repertorie genes were amplified by RT-PCR from PBMC in patients with prostate cancer, and cloned into the phagemid vector pComb3X with murine Fd gene against gamma-seminoprotein to construct the human-mouse hybrid Fab antibody library. The size of the library, antibody gene recombinant percentage and diversity were identified by colony counting, plasmid digestion and colony sequence analysis, respectively. Purified gamma-sm was used as antigen to screen the displayed phage hybrid antibody library rescued by helper phage M13K07 for three rounds. The positive clones were selected by ELISA with pIII-fusion antibody and then the sequences of light gene in the positive clones were analyzed by IMGT-VQUEST.
Results: A 1.2x10(7) CPU human-mouse Fab antibody library was constructed with 90% Lc gene recombinant and great diversity. After 3 rounds' panning with gamma-sm, 5 positive clones were selected by ELISA and 2 clones with higher affinity were selected. Sequence analysis suggested these two positive clones contained the same light gene with high V(L) homology to human germline gene IGKV4-1*01.
Conclusion: Human anti-gamma-sm light chain was successfully screened by constructing mouse-human hybrid Fab phage antibody library with murine Fd-guided selection.