Quantitative expression of Toll-like receptor-2, -4, and -9 in dendritic cells generated from blasts of patients with acute myeloid leukemia.
BACKGROUND
Dendritic cells (DCs) generated from leukemic blasts constitute a promising tool in immunotherapy for acute myeloid leukemia patients (AML-DCs), because AML-DCs express human leukocyte antigens and costimulatory molecules such as CD40, CD80, and CD86 at a higher level than leukemic blasts. Potentiation of AML-DC vaccine might become feasible by the addition of adjuvants such as lipopolysaccharides (LPS) or CPG-rich oligodeoxyribonucleotides binding to Toll-like receptors (TLR) and inducing a stronger Type 1 T-cell response.


METHODS
mRNA and protein expression of TLR-2, -4, and -9 were analyzed with quantitative real-time polymerase chain reaction, Western blot, and flow cytometry for mature monocyte-derived DCs generated from 14 AML patients versus 14 healthy volunteers (HV-DCs), and the response of the AML- and HV-DCs to different microbial TLR ligands was determined by enzyme-linked immunosorbent assay for the proinflammatory cytokines tumor necrosis factor (TNF)-alpha, inducible protein (Ip)-10, and interleukin (IL)-6.


RESULTS
AML-DCs and HV-DCs strongly expressed TLR-2 and TLR-4, while TLR-9 was expressed at a lower level in both groups. There was no significant difference in TLR expression between the two groups of AML-DCs and HV-DCs. In accordance with the TLR expression levels, DCs generated from both AML patients and HVs responded to the known microbial ligands peptidoglycan (PGN) and lipoteichoic acid for TLR-2 and LPS as ligand for TLR-4, by producing TNF-alpha and IL-6. A response to the ODNs 2006 and 2216 binding to TLR-9 was only detected in AML-DCs.


CONCLUSIONS
Microbial ligands like ODNs and LPS constitute promising adjuvants for enhancing (AML-) DC vaccines.
Schmitt
Anita
A
Institute for Clinical Transfusion Medicine and Immunogenetics (IKT) gGmbH Ulm, University of Ulm, Ulm, Germany.
Li
Li
L
Giannopoulos
Krzysztof
K
Greiner
Jochen
J
Reinhardt
Peter
P
Wiesneth
Markus
M
Schmitt
Michael
M
D000328:Adult; D000368:Aged; D019496:Cancer Vaccines; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000187:drug effects / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D016130:Immunophenotyping; D007167:Immunotherapy / Q000379:methods*; D015470:Leukemia, Myeloid, Acute / Q000276:immunology / Q000503:physiopathology* / Q000628:therapy*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000502:physiology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology; D010457:Peptidoglycan / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D051217:Toll-Like Receptor 9 / Q000235:genetics / Q000378:metabolism; D051193:Toll-Like Receptors / Q000235:genetics* / Q000378:metabolism
D019496:Cancer Vaccines; D016207:Cytokines; D008070:Lipopolysaccharides; D009838:Oligodeoxyribonucleotides; D010457:Peptidoglycan; D012333:RNA, Messenger; C495342:TLR2 protein, human; C495345:TLR4 protein, human; C495371:TLR9 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors