Human monoclonal antibodies to viral peptides

A new approach to the developing of human monoclonal antibodies to viral peptides is described. The method is based on the positive selection of B cells specific to viral peptides from normal human tissues. To isolate B cells bearing immunoglobulin receptors specific to viral epitopes magnetic beads coated by viral peptides were used. Human B lymphocytes specific to the neutralizing epitope of gp120 of human immunodeficiency virus and to the major epitope of Epstein-Barr nuclear antigen-I were isolated from freshly removed human tonsils. Preselected cells were transformed by Epstein-Barr virus and cultivated on irradiated human embryonic lung fibroblasts in RPMI 1640-OptiMEM medium with 10% fetal calf serum and all necessary supplements. The cultures of B cells producing antibodies to viral epitopes used for selection were obtained. Two cultures secreting IgM antibodies to the peptide MN-24 (neutralizing epitope of immunodeficiency virus) and to the peptide p107 of Epstein-Barr nuclear antigen-1 were expanded, and the specificity of the antibodies and antibody-producing cells was analyzed. The method of positive selection of B cells specific to viral peptides may be used for the preparation of human monoclonal antibodies to viral antigens.