A newly developed method using rat lymph nodes provided us with substantial amounts of high quality monoclonal antibodies. The method has characteristic features, a single injection of an emulsified antigen via the rat's hind footpads is sufficient for immunization. Enlarged medial iliac lymph nodes can be used for cell fusion to produce hybridomas 2 weeks and later after the antigen injection. The production frequency of target hybridomas is about 10 times higher than that of a conventional spleen method. Our current knowledge about the production of monoclonal antipeptide antibodies and monoclonal nephritogenic autoantibodies by the method is described.