Human monoclonals from antigen-specific selection of B lymphocytes and transformation by EBV

Hybridoma technology has made it possible to prepare monoclonal antibodies with the use of murine lymphocytes. Attempts to extend this technology to the human level, however, have met with difficulties. A method has been developed for making human monoclonal antibodies of predetermined specificity. Biotinylated antigens (human thyroglobulin or tetanus toxoid) were incubated with human B lymphocytes from peripheral blood. The lymphocytes to which the antigens bound were selected by fluorescence-activated cell sorting. Positively selected (high fluorescence) and negatively selected (low fluorescence) cells were then transformed with Epstein-Barr virus (EBV) and grown in microculture wells. All wells from the positively selected fraction produced antigen-specific antibody (95 to 1800 nanogram-equivalents per milliliter), whereas fewer than 6% of the wells from negatively selected fraction made any detectable antibody (less than 10 nanogram-equivalents per milliliter). When the positively selected EBV-transformed cells were cultured in limiting dilution, clones were obtained that made antigen-specific monoclonal antibodies. By this method, monoclonal antibodies to both foreign antigens and autoantigens can be prepared from the normal human B-cell repertoire.