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pubmed:abstractText |
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: 76.1-62.3%; 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.
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