Generation of human monoclonal antibodies reactive with cellular antigens.

Abstract

Human lymphocytes from lymph node, peripheral blood, spleen and tumor specimens were fused with the LICR-LON-HMy2 (LICR-2) [human lymphoblastoid cells]) or SKO-007 human [myeloma] cell lines or the NS-1 mouse myeloma line. Over 75 fusions with the 3 myeloma-lymphoblastoid lines were performed. Several factors appeared to improve the fusion outcome, including maintenance of the myeloma-lymphoblastoid lines in logarithmic phase growth at .gtoreq. 95% viability, a delay of 24 h in the introduction of aminopterin to the fused cells and preselection of the fetal calf serum used in the medium. For a given number of lymphocytes, fusions with NS-1 produced 5-20 times more clones than fusions with LICR-2 or SKO-007, and LICR-2 produced 4 times as many clones as SKO-007. The percentage of clones secreting human Ig, the range of Ig production, and the proportion of IgM, IgA and IgG secretors were comparable for clones derived from the 3 myeloma-lymphoblastoid lines. Stable Ig-secreting clones were isolated with approximately equal frequency from LICR-2 and NS-1 fusions. A number of stable clones producing human monoclonal antibodies reacting with cell-surface, cytoplasmic or nuclear antigens were isolated from tumor-bearing patients and normal individuals. A surface antigenic system present on normal and malignant cells was defined with a human monoclonal antibody derived from a patient with breast cancer. Techniques for producing human monoclonal antibody now appear to be sufficiently advanced to initiate a serological dissection of the humoral immune response to cancer.