Human monoclonal antibodies derived from lymph nodes of a patient with breast carcinoma react with MuMTV polypeptides.

Nine human hybridoma cell lines were established from a fusion of axillary lymph node lymphocytes of a patient with breast ductal carcinoma with a human lymphoblastoid cell line. The human hybridoma nature of the fusion products was confirmed by chromosomal analysis and HLA typing. The hybridomas are stable over a year of growth, and can be frozen, thawed and regrown. The carcinoma cells of the patient harbor mouse mammary tumor virus (MuMTV) cross-reacting antigens. The patient's serum and the purified monoclonal antibodies reacted with MuMTV polypeptides. Radioimmunoprecipitation studies using labeled MuMTV confirmed the binding of the patient's serum to the viral proteins. None of the control immunoglobulins reacted with the virus. No binding of the hybridoma immunoglobulins was observed with two other retroviruses (avian myeloblastosis virus and simian sarcoma virus). The ligand binding characteristics of the monoclonal antibodies suggest binding to epitopes on the various structural virus polypeptides. These monoclonal antibodies may serve as a probe to analyze the MuMTV-human breast carcinoma relationship.