title: Antigen-specific deletion of cloned T cells using peptide-toxin conjugate complexed with purified class II major histocompatibility complex antigen.
abstract: In a previous report, we showed that cloned T cells incubated with soluble, cognate major histocompatibility complex (MHC) II-peptide complex internalized the peptide moiety of the complex. Here, we report antigen-specific deletion of cloned T cells by treatment with soluble, cognate MHC II-(peptide-toxin) complexes. Toxin (doxorubicin or mycophenolic acid) was attached to synthetic AcMBP(1-14)Ala4 peptide, an analog of the natural acetylated NH2-terminal segment, AcMBP(1-14), of rat myelin basic protein (MBP). IAk-restricted, AcMBP(1-14)-Specific AJ1.2 and 4R3.9 cloned murine T cells were killed by IAk-(AcMBP(1-14)Ala4-toxin). No killing resulted from incubating AJ1.2 and 4R3.9 cells with irrelevant MHC II-(peptide-toxin) or treating IEk-restricted, pigeon cytochrome c-specific A.E7 cloned murine T cells with IAk-(AcMBP(1-14)Ala4-toxin). T cell receptor-mediated T cell uptake of the peptide-toxin moiety of relevant complex was blocked by anti-T cell receptor-alpha/beta antibody and by excess toxin-free complex. LD50 determinations revealed that cognate MHC II-(peptide-toxin) killed T cells much more effectively than did peptide-toxin conjugate alone. Finally, T cell uptake of peptide-toxin and intracellular release of toxin occurred after incubation with relevant MHC II-(peptide-toxin) containing radiolabeled toxin. These findings, which provide the first evidence that cloned T cells can be deleted with soluble, cognate MHC II-(peptide-toxin) complexes, may have significant clinical relevance for antigen-specific therapy of autoimmune or other T cell-mediated diseases.
authors.affiliation: Anergen, Inc., Redwood City, California 94063.
authors.forename: B R
authors.initials: BR
authors.lastname: Clark
authors.forename: S V
authors.initials: SV
authors.lastname: Deshpande
authors.forename: S D
authors.initials: SD
authors.lastname: Sharma
authors.forename: B
authors.initials: B
authors.lastname: Nag
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017637:Clonal Deletion; D002999:Clone Cells; D004317:Doxorubicin / Q000494:pharmacology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000494:pharmacology; D000922:Immunotoxins / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D051379:Mice; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009173:Mycophenolic Acid / Q000494:pharmacology*; D004676:Myelin Basic Protein / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects
chemical_list: D000949:Histocompatibility Antigens Class II; D000922:Immunotoxins; D004676:Myelin Basic Protein; D004317:Doxorubicin; D009173:Mycophenolic Acid