Specificity analysis of human monoclonal antibodies reactive with cell surface and intracellular antigens

Over 4350 human Ig-secreting hybrids have been generated through the fusion of human lymphocytes with NS-1 (mouse), LICR-2, SKO-007, GM4672, or UC729-6 (human) myeloma and lymphoblastoid cell lines. NS-1 proved to be the most satisfactory fusion partner, and 83% of the stable Ig-secreting clones were derived from NS-1 fusions. Three hundred five hybrids produced human monoclonal antibodies (hmAb) reactive with cell surface or intracellular antigens expressed by cultured human tumor cell lines, and 111 of these have undergone detailed serological specificity anaylsis. Several general points have emerged from our study of hmAb: (i) A significant proportion of the human B-cell clones produce antibody reactive with cellular antigens. (ii) The majority of these antigens have an intracellular location and are broadly distributed. (iii) Intracellular and cell surface differentiation antigens and other antigens with restricted distribution have been defined by hmAb, including two cell surface antigens not detected on normal cells. (iv) The relationship of these findings to cancer is unclear, as hmAb reactive with antigens showing distinctive distribution have been generated from the lymphocytes of normal individuals as well as tumor-bearing patients.