VS38 - A NEW MONOCLONAL-ANTIBODY FOR DETECTING PLASMA-CELL DIFFERENTIATION IN ROUTINE SECTIONS

Aims-To characterise a new mouse monoclonal antibody, VS38, which reco gnises an intracytoplasmic antigen of 64 kilodaltons present in normal and neoplastic plasma cells; and to establish its value as a diagnost ic reagent for routine pathological practice. Methods-A range of norma l and neoplastic tissue sections, both frozen and routinely fixed, wer e immunostained, using the microwave method of antigen retrieval for r outinely fixed specimens. The antibody was also tested on blood and bo ne marrow specimens and a range of human cell Lines. The molecular wei ght of the antigen recognised by the antibody was obtained by western blot analysis. FACS analysis was used to demonstrate the cellular loca tion of the antigen and its presence on tonsil cell suspensions and my eloma cases. Results-VS38 recognised normal and neoplastic plasma cell s in all of the tissues, including all routinely fixed plasma cell neo plasms tested, The antibody also weakly stained epithelial elements wi thin the tissue but was absent from haemopoietic cells of other lineag es. Conclusion-Antibody VS38 is of potential value in identifying myel oma or plasmacytoma in bone marrow or other tissues. It differentiates lymphoplasmacytoid lymphoma from lymphocytic and follicular lymphoma. It also subdivides large cell lymphomas into two groups which may be a more reliable method of separating these tumours than morphology alo ne.