Human X (mouse X human) hybridomas stably producing human antibodies.

A method is described for constructing mouse heterohybridomas producing human monoclonal antibody with a high stability. The essence of the method is the use of a nonsecretor mouse X human hybridoma which has been made 8-azaguanine resistant as a fusion parent for construction of (mouse X human) X human hybridomas. The production of four human anti-influenza antibodies is described. The cells have now been maintained for more than 22 months in culture.