Human monoclonal antibody. Construction of stable clones reactive with human breast cancer.

A human clone was derived from fusion of a malignant cell line (Ball-1) and peripheral blood lymphocytes from a breast cancer patient in long-term remission. This clone, JDB1, was shown to be a genetically identifiable hybrid, expressing chromosomes unique to each of the parental cell types. The JDB1 clone produces IgG/lambda molecules which are extremely reactive with breast tumor cells, but do not bind to normal breast tissue or other types of malignant tissue. This hybrid was constructed without using the commonly accepted fusion technology which employs 8-azoguanine resistant HAT sensitive malignant fusion partners. Rather a selective fusion procedure was used in which a choice of the most efficient and effective malignant partner could be made prior to fusion. This approach was accompanied by stringent selection of patients as lymphocyte donors. This method has allowed for stable and vigorous growth of clones with a near constant amount of specific immunoglobulin production and a normal diploid chromosome number for over 3 years.