Cell contact-dependent priming and Fc interaction with CD32+ immune cells contribute to the TGN1412-triggered cytokine response.
Following inconspicuous preclinical testing, the superagonistic anti-CD28 mAb TGN1412 was applied to six study participants who all developed a devastating cytokine storm. We verified that TGN1412 treatment of fresh PBMCs induced only moderate responses, whereas restoration of tissue-like conditions by high-density preculture (HDC) allowed vigorous cytokine production. TGN1412 treatment of T cells isolated from HDC-PBMCs induced moderate cytokine responses, which upon additional anti-IgG crosslinking were significantly boosted. Moreover, coincubation of TGN1412-treated T cells with B cells expressing the intermediate affinity Fcγ receptor IIB (CD32B), or coincubation with CD32B(+) transfectants, resulted in robust T cell activation. This was surprising because TGN1412 was expressed as an Ig of the subclass 4 (IgG4), which was shown before to exhibit only minor affinity to FcγRs. Transcriptome analysis of TGN1412-treated T cells revealed that similar gene signatures were induced irrespective of whether T cells derived from fresh or HDC-PBMCs were studied. Collectively, these data indicate that HDC-PBMCs and HDC-PBMC-derived T cells mount rapid TGN1412 responses, which are massively boosted by FcγR crosslinking, in particular by CD32-expressing B cells. These results qualify HDC-PBMCs as a valuable in vitro test system for the analysis of complex mAb functions.
Institute for Experimental Infection Research, TWINCORE, Center for Experimental and Clinical Infection Research, Helmholtz Centre for Infection Research, Braunschweig, and Hannover Medical School, 30625 Hannover, Germany;
Patrick
P
Bartholomaeus
Linda Y
LY
Semmler
Thomas
T
Bukur
Valesca
V
Boisguerin
Paula S
PS
Römer
Paula
P
Tabares
Sergey
S
Chuvpilo
Dmitry Y
DY
Tyrsin
Alexey
A
Matskevich
Hartmut
H
Hengel
John
J
Castle
Thomas
T
Hünig
Ulrich
U
Kalinke
D061067:Antibodies, Monoclonal, Humanized / Q000276:immunology / Q000494:pharmacology*; D016207:Cytokines / Q000276:immunology*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000276:immunology; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000276:immunology / Q000494:pharmacology*; D007074:Immunoglobulin G / Q000276:immunology / Q000494:pharmacology*; D008297:Male; D017452:Receptors, IgG / Q000276:immunology*; D059467:Transcriptome / Q000187:drug effects / Q000276:immunology
D061067:Antibodies, Monoclonal, Humanized; D016207:Cytokines; C080571:Fc gamma receptor IIB; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D017452:Receptors, IgG; C509303:TGN-1412