title: Cell-type specificity of l-leucyl l-leucine methyl ester.
abstract: l-Leucyl l-leucine methyl ester (LeuLeuOMe) is a lysosomotropic agent which is converted to a membranolytic compound by dipeptidyl peptidase I and kills human leukocytes such as CD8+ T cells and monocytes but not B cells. The reagent has also been used in mice on the assumption that the cell-type specificity to murine leukocytes is the same as that to human leukocytes. During study on the effect of LeuLeuOMe on antigen-driven IL-2 production using murine splenocytes as antigen-presenting cells, however, we noticed that murine B cells were sensitive to LeuLeuOMe. We therefore examined the cell-type specificity using murine splenocytes and peritoneal macrophages. Flow cytometric analysis revealed that the most sensitive cells to LeuLeuOMe were CD8+ cells and that CD19+ cells (B cells) were as sensitive as CD3+ cells (T cells). Murine splenic B cells, which were either positively or negatively sorted with a cell sorter, were also sensitive to LeuLeuOMe, whereas human peripheral blood B cells, which were positively sorted, were not. Peritoneal macrophages were the most insensitive to LeuLeuOMe. Thus, this study demonstrated that the cell-type specificity to murine leukocytes is different from that to human leukocytes.
authors.affiliation: Department of Biomolecular Science, Faculty of Science, Toho University, Chiba, Japan. yoshiro@biomol.sci.toho-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: A
authors.initials: A
authors.lastname: Takasaki
authors.forename: K
authors.initials: K
authors.lastname: Kurosaka
authors.forename: Y
authors.initials: Y
authors.lastname: Sakurai
authors.forename: M
authors.initials: M
authors.lastname: Iwamura
authors.forename: N
authors.initials: N
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D017209:Apoptosis / Q000187:drug effects; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects*; D048429:Cell Size / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004151:Dipeptides / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D020128:Inhibitory Concentration 50; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000187:drug effects*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009928:Organ Specificity; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D013864:Thioglycolates / Q000494:pharmacology
chemical_list: D015703:Antigens, CD; D004151:Dipeptides; D013864:Thioglycolates; C045139:leucyl-leucine-methyl ester