title: Ipilimumab augments antitumor activity of bispecific antibody-armed T cells.
abstract: BACKGROUND
  Ipilimumab is an antagonistic monoclonal antibody against cytotoxic T-lymphocyte antigen-4 (CTLA-4) that enhances antitumor immunity by inhibiting immunosuppressive activity of regulatory T cells (Treg). In this study, we investigated whether inhibiting Treg activity with ipilimumab during ex vivo T cell expansion could augment anti-CD3-driven T cell proliferation and enhance bispecific antibody (BiAb)-redirected antitumor cytotoxicity of activated T cells (ATC).
  
  
  METHODS
  PBMC from healthy individuals were stimulated with anti-CD3 monoclonal antibody with or without ipilimumab and expanded for 10-14 days. ATC were harvested and armed with anti-CD3 x anti-EGFR BiAb (EGFRBi) or anti-CD3 x anti-CD20 BiAb (CD20Bi) to test for redirected cytotoxicity against COLO356/FG pancreatic cancer cell line or Burkitt's lymphoma cell line (Daudi).
  
  
  RESULTS
  In PBMC from healthy individuals, the addition of ipilimumab at the initiation of culture significantly enhanced T cell proliferation (p = 0.0029). ATC grown in the presence of ipilimumab showed significantly increased mean tumor-specific cytotoxicity at effector:target (E:T) ratio of 25:1 directed at COLO356/FG and Daudi by 37.71% (p < 0.0004) and 27.5% (p < 0.0004), respectively, and increased the secretion of chemokines (CCL2, CCL3, CCL4,CCL5, CXCL9, and granulocyte-macrophage colony stimulating factor(GM-CSF)) and cytokines (IFN-γ, IL-2R, IL-12, and IL-13), while reducing IL-10 secretion.
  
  
  CONCLUSIONS
  Expansion of ATC in the presence of ipilimumab significantly improves not only the T cell proliferation but it also enhances cytokine secretion and the specific cytotoxicity of T cells armed with bispecific antibodies.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yano
authors.forename: Archana
authors.initials: A
authors.lastname: Thakur
authors.forename: Elyse N
authors.initials: EN
authors.lastname: Tomaszewski
authors.forename: Minsig
authors.initials: M
authors.lastname: Choi
authors.forename: Abhinav
authors.initials: A
authors.lastname: Deol
authors.affiliation: Departments of Oncology, Wayne State University and Barbara Ann Karmanos Cancer Institute, 740,1 Hudson Webber Cancer Research Center, 4100 John R,, Detroit, MI 48201, USA. luml@karmanos.org.
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lum
mesh_terms: D018033:Antibodies, Bispecific / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D017252:CD3 Complex / Q000276:immunology; D060908:CTLA-4 Antigen / Q000276:immunology; D045744:Cell Line, Tumor; D006801:Humans; D000074324:Ipilimumab; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D060908:CTLA-4 Antigen; D000074324:Ipilimumab