Affiliations: Department of Surgery, University Medical School, Aberdeen, Scotland, UK
Note: [] Address reprint requests to Dr. Y. Li, Department of Allergy and Allied Respiratory Disorders, 18th Floor, Guy's Tower, Guys' Hospital, London SE1 9RT, UK.
Abstract: The selective cytotoxicity of the lysosomotropic leucine methyl ester and its lysosomal condensation product leucyl-leucine methyl ester have been used to investigate their effect on a range of lymphocyte subsets and on the cellular proliferation and secretion by immunoglobulin-secreting B cells from axillary regional draining lymph nodes of breast cancer patients. CD2+, CD3+, and CD8+ lymphocyte subsets were selectively reduced by the leucyl-leucine methyl ester treatment (CD2: 84.2–67.5%; CD3:76.I–62.3%; and CD8: 8.0–3.4%), but there was no significant reduction in the CD4+ and CD19+ subsets (CD4: 68.2–64.7%; and CD19: 22.6–33.2%). In the presence of mouse splenic macrophages as antigen-presenting cells, rIL-2, IFN-gamma, and pokeweed mitogen-stimulated lymphocyte supernatant, leucyl-leucine methyl ester-treated lymphocytes showed a significant increase in 3H-thymidine incorporation and in the number of immunoglobulin-secreting B cells following coculture with the breast tumor cell line MCF-7. In this study, we have characterized some of the cellular and cytokine factors that are necessary for in vitro immunization of human B lymphocytes. Hopefully, this will enable human MAbs to be produced in vitro against tumor-associated antigens.
Keywords: in vitro immunization, human monoclonal antibody, tumor-associated antigen, breast cancer
