title: Targeting of CD4+CD25high cells while preserving CD4+CD25low cells with low-dose chimeric anti-CD25 antibody in adoptive immunotherapy of cancer.
abstract: The CD4+CD25high regulatory T (Treg) cells have been demonstrated to negatively modulate anti-tumor immune responses in cancer patients. In this study, effects of low dose anti-CD25 antibody (Ab) to attenuate Treg cells were investigated in cancer patients in vitro and in vivo. Peripheral blood mononuclear cells (PBMCs) from cancer patients were cultivated in vitro in the presence of a high-affinity chimeric anti-CD25 Ab (basiliximab). The CD4+CD25high population, interferon-gamma (IFN-gamma) production and FOXP3 expression were analyzed using flow cytometry (FCM), enzyme-linked immunosorbent assay and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, respectively. During in vivo studies, basiliximab was administered intravenously on day 1, followed by AIT using autologous activated lymphocytes on day 8, and the treatment cycle was repeated. Subjective and objective effects were observed, and patients' PBMCs were subjected to FCM and RT-PCR analysis. In vitro analysis revealed that a low concentration of 0.01 microg/ml basiliximab reduced almost all of CD4+CD25high cells, but less of the CD4+ CD25low cells, and augmented IFN-gamma production of activated PBMCs. FOXP3 mRNA expression of PBMCs was not affected with or without basiliximab. An in vivo study of 9 metastatic cancer patients (7 colorectal and 2 esophageal) demonstrated no subjective or objective adverse effects, even under repeated administration of basiliximab. The results suggested that low-dose basiliximab can safely be administered repeatedly, and can target CD4+CD25high Treg cells whilst relatively preserving CD4+CD25low activated T cells. The host conditioning with low-dose basiliximab may augment the efficacy of AIT for cancer using activated autologous lymphocytes.
authors.affiliation: Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan.
authors.forename: Riki
authors.initials: R
authors.lastname: Okita
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ohara
authors.forename: Katsuji
authors.initials: K
authors.lastname: Hironaka
authors.forename: Makoto
authors.initials: M
authors.lastname: Okawaki
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nagamine
authors.forename: Takuhiro
authors.initials: T
authors.lastname: Ikeda
authors.forename: Akiko
authors.initials: A
authors.lastname: Emi
authors.forename: Jun
authors.initials: J
authors.lastname: Hihara
authors.forename: Morihito
authors.initials: M
authors.lastname: Okada
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D015703:Antigens, CD / Q000276:immunology*; D000077552:Basiliximab; D018801:CD2 Antigens / Q000276:immunology*; D015704:CD4 Antigens / Q000276:immunology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000276:immunology; D017931:DNA Primers; D004938:Esophageal Neoplasms / Q000276:immunology; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000276:immunology; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016219:Immunotherapy, Adoptive / Q000379:methods*; D007376:Interleukin-2 / Q000276:immunology; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation; D009369:Neoplasms / Q000276:immunology*; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000627:therapeutic use; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018801:CD2 Antigens; D015704:CD4 Antigens; D017931:DNA Primers; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D011993:Recombinant Fusion Proteins; D000077552:Basiliximab