title: Signaling signatures and functional properties of anti-human CD28 superagonistic antibodies.
abstract: Superagonistic CD28 antibodies (CD28SAs) activate T lymphocytes without concomitant perturbation of the TCR/CD3-complex. In rodents these reagents induce the preferential expansion of regulatory T cells and can be used for the treatment of autoimmune diseases. Unexpectedly, the humanized CD28 superagonist TGN1412 caused severe and life threatening adverse effects during a recently conducted phase I clinical trail. The underlying molecular mechanisms are as yet unclear. We show that TGN1412 as well as the commercially available CD28 superagonist ANC28.1 induce a delayed but extremely sustained calcium response in human naïve and memory CD4+ T cells but not in cynomolgus T lymphocytes. The sustained Ca++-signal was associated with the activation of multiple intracellular signaling pathways and together these events culminated in the rapid de novo synthesis of high amounts of pro-inflammatory cytokines, most notably IFN-gamma and TNF-alpha. Importantly, sustained transmembranous calcium flux, activation of Src-kinases as well as activation of PI3K were found to be absolutely required for CD28SA-mediated production of IFN-gamma and IL-2. Collectively, our data suggest a molecular basis for the severe side effects caused by TGN1412 and impinge upon the relevance of non-human primates as preclinical models for reagents that are supposed to modify the function of human T cells.
authors.affiliation: Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Waibler
authors.forename: Linda Y
authors.initials: LY
authors.lastname: Sender
authors.forename: Camilla
authors.initials: C
authors.lastname: Merten
authors.forename: Roland
authors.initials: R
authors.lastname: Hartig
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kliche
authors.forename: Matthias
authors.initials: M
authors.lastname: Gunzer
authors.forename: Peter
authors.initials: P
authors.lastname: Reichardt
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kalinke
authors.forename: Burkhart
authors.initials: B
authors.lastname: Schraven
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D015153:Blotting, Western; D018106:CD28 Antigens / Q000276:immunology*; D002118:Calcium / Q000378:metabolism*; D049109:Cell Proliferation; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation; D008252:Macaca fascicularis; D008253:Macaca mulatta; D011812:Quinuclidines / Q000276:immunology / Q000494:pharmacology; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018106:CD28 Antigens; D007376:Interleukin-2; D011812:Quinuclidines; D014409:Tumor Necrosis Factor-alpha; C038895:ANC 821; D007371:Interferon-gamma; D019061:src-Family Kinases; C509303:TGN-1412; D002118:Calcium