Generation of a Human Anti-Tumor Necrosis Factor-α Monoclonal Antibody by in VitroImmunization with a Multiple Antigen Peptide

We developed the in vitroimmunization method to induce antigen-specific immune responses in human peripheral blood mononuclear cells (PBMCs). However, when we used a peptide as sensitizing antigen, the antigen-specific immune response was found to be weak, and hence, we could not effectively obtain the antigen-specific antibody gene. In the present study, we attempted to improve the in vitroimmunization method by augmenting the immune response to the peptide antigen. We used a multiple antigen peptide for sensitization. In vitroimmunization of the multivalent antigen elicited a strong antigen-specific immune response in the PBMCs, and we succeeded in obtaining antigen-specific antibody genes by the phage-display method. Further, by combining the variable-region genes and constant-region genes of human IgG, we obtained four independent human monoclonal antibodies specific for tumor necrosis factor-α. This might be a good strategy for generating antigen-specific human monoclonal antibodies using a peptide antigen.