Improving In Vitro Antibody Production Using Synthetic Peptide Derived from RhD Loops.
Source: PubMed, NCBI / U.S. National Library of Medicine
the RhD antigen is highly immunogenic, and poses a significant clinical risk of hemolytic transfusion reactions (HTRs), rendering it a critical factor in safe blood transfusion. Conventional immunization strategies relying on full-length RhD protein are limited by restricted antigen availability, high production costs, and ethical concerns associated with in vivo antibody generation. To address these challenges, we evaluated an in vitro immunization platform using human peripheral blood mononuclear cells (PBMCs) stimulated with either full length RhD protein or a designed synthetic RhD peptide, aiming to establish a rapid, ethical, and reproducible biotechnological alternative for in vitro antibody production. PBMCs from O-negative blood units were isolated by Ficoll density gradient, and treated with L-leucine methyl ester to deplete immunosuppressive cells. PBMCs were stimulated with full length RhD protein, synthetic peptide, or peptide conjugated to Keyhole Limpet Hemocyanin (KLH). Conjugation efficiency was confirmed via ELISA and spectrophotometry (280/412 nm). Cultures were supplemented with IL-4, IFN-γ, and conditioned medium, and then incubated at 37°C for one week. Antibody production in culture supernatants was quantified by ELISA. Peptide-KLH induced higher antibody levels (84.87±13.6 ng/mL) than free peptide (52.4±9.8 ng/mL), while RhD protein elicited (108.7±10.4 ng/mL). Combined stimulation with peptide-KLH and RhD protein further enha
Abstract
the RhD antigen is highly immunogenic, and poses a significant clinical risk of hemolytic transfusion reactions (HTRs), rendering it a critical factor in safe blood transfusion. Conventional immunization strategies relying on full-length RhD protein are limited by restricted antigen availability, high production costs, and ethical concerns associated with in vivo antibody generation. To address these challenges, we evaluated an in vitro immunization platform using human peripheral blood mononuclear cells (PBMCs) stimulated with either full length RhD protein or a designed synthetic RhD peptide, aiming to establish a rapid, ethical, and reproducible biotechnological alternative for in vitro antibody production. PBMCs from O-negative blood units were isolated by Ficoll density gradient, and treated with L-leucine methyl ester to deplete immunosuppressive cells. PBMCs were stimulated with full length RhD protein, synthetic peptide, or peptide conjugated to Keyhole Limpet Hemocyanin (KLH). Conjugation efficiency was confirmed via ELISA and spectrophotometry (280/412 nm). Cultures were supplemented with IL-4, IFN-γ, and conditioned medium, and then incubated at 37°C for one week. Antibody production in culture supernatants was quantified by ELISA. Peptide-KLH induced higher antibody levels (84.87±13.6 ng/mL) than free peptide (52.4±9.8 ng/mL), while RhD protein elicited (108.7±10.4 ng/mL). Combined stimulation with peptide-KLH and RhD protein further enhanced antibody levels (157.9±23.6 ng/mL). Two-step immunization significantly enhanced responses (P=0.006). The combination of IL-4 and IFN-γ yielded the highest cytokine-driven enhancement. Synthetic RhD peptide, especially when conjugated to KLH, provides an attractive and convenient alternative to full-length protein for in vitro antibody production. This approach has practical applications in biotechnology, including the generation of antibodies and antibody producing clones, reducing reliance on in vivo immunization.