title: Rational design of low immunogenic anti CD25 recombinant immunotoxin for T cell malignancies by elimination of T cell epitopes in PE38.
abstract: LMB-2, is a potent recombinant immunotoxin (RIT) that is composed of scFv antibody that targets CD25 (Tac) and a toxin fragment (PE38). It is used to treat T cell leukemias and lymphomas. To make LMB-2 less immunogenic, we introduced a large deletion in domain II and six point mutations in domain III that were previously shown to reduce T cell activation in other RITs. We found that unlike other RITs, deletion of domain II from LMB-2 severely compromised its activity. Rather than deletion, we identified T cell epitopes in domain II and used alanine substitutions to identify point mutations that diminished those epitopes. The novel RIT, LMB-142 contains a 38kDa toxin and nine point mutations that diminished T cell response to the corresponding peptides by an average of 75%. LMB-142 has good cytotoxic activity and has lower nonspecific toxicity in mice. LMB-142 should be more efficient in cancer therapy because more treatment cycles can be given.
authors.affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892-4264, USA. Electronic address: mazorr@mail.nih.gov.
authors.forename: Ronit
authors.initials: R
authors.lastname: Mazor
authors.affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892-4264, USA. Electronic address: kaplang@medimmune.com.
authors.forename: Gilad
authors.initials: G
authors.lastname: Kaplan
authors.affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892-4264, USA. Electronic address: Parkkoon77@gmail.com.
authors.forename: Dong
authors.initials: D
authors.lastname: Park
authors.affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892-4264, USA. Electronic address: yjj8817@gmail.com.
authors.forename: Youjin
authors.initials: Y
authors.lastname: Jang
authors.affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892-4264, USA. Electronic address: fred.lee@nih.gov.
authors.forename: Fred
authors.initials: F
authors.lastname: Lee
authors.affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892-4264, USA. Electronic address: kreitmar@mail.nih.gov.
authors.forename: Robert
authors.initials: R
authors.lastname: Kreitman
authors.affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892-4264, USA. Electronic address: pastani@mail.nih.gov.
authors.forename: Ira
authors.initials: I
authors.lastname: Pastan
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000627:therapeutic use*; D001427:Bacterial Toxins / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016207:Cytokines / Q000378:metabolism; D015195:Drug Design; D058501:Enzyme-Linked Immunospot Assay; D018984:Epitopes, T-Lymphocyte / Q000235:genetics; D005098:Exotoxins / Q000235:genetics / Q000627:therapeutic use; D005260:Female; D005818:Genetic Engineering; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D000922:Immunotoxins / Q000235:genetics / Q000627:therapeutic use*; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D015458:Leukemia, T-Cell / Q000276:immunology / Q000628:therapy*; D008213:Lymphocyte Activation; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D011549:Pseudomonas / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; C077707:B3(Fv)-PE38KDEL recombinant immunotoxin; D001427:Bacterial Toxins; D016207:Cytokines; D018984:Epitopes, T-Lymphocyte; D005098:Exotoxins; D000922:Immunotoxins; D053645:Interleukin-2 Receptor alpha Subunit
keywords: Deimmunization; Domain II; IL2 receptor; Immunogenicity; Pseudomonas exotoxin A; RIT; T cell epitopes; TAC