title: Adenosine mediated desensitization of cAMP signaling enhances T-cell responses.
abstract: Adenosine has long been regarded as a crucial anti-inflammatory agent that protects the host from excessive damage. It has been reported to play an important role in suppressing immune activation, particularly that of T cells. However, it is a general observation that induction of T-cell activation is an efficient event despite the high adenosine levels that are often present in the affected host due to injury or stress. We report here that prior to antigenic stimulation via TCR/CD3, exposure of T cells to adenosine desensitizes adenosine receptors, so as to create a window of time where the T cells are insensitive to this ubiquitous suppressor. T cells from mice that were pre-exposed to this manipulation showed stronger responses to antigenic stimulation; therefore, the P1 adenosine receptor desensitization demonstrated an adjuvant-like effect. Our results suggest that adenosine receptor desensitization may be a mechanism for T cells to escape the general suppression during early points of T-cell activation and may emerge as a potential alternative for vaccine adjuvants.
authors: Immunology Research Group and Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alta., Canada.
authors: Ailian
authors: A
authors: Yang
authors: Ashley D
authors: AD
authors: Mucsi
authors: Melanie D
authors: MD
authors: Desrosiers
authors: Jiang-Fan
authors: JF
authors: Chen
authors: Jürgen B
authors: JB
authors: Schnermann
authors: Michael R
authors: MR
authors: Blackburn
authors: Yan
authors: Y
authors: Shi
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D058907:Adenosine A1 Receptor Agonists; D058916:Adenosine A1 Receptor Antagonists; D058908:Adenosine A2 Receptor Agonists; D058917:Adenosine A2 Receptor Antagonists; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D043682:Receptor, Adenosine A1 / Q000235:genetics; D043705:Receptor, Adenosine A2A / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D014970:Xanthines / Q000494:pharmacology
chemical_list: D058907:Adenosine A1 Receptor Agonists; D058916:Adenosine A1 Receptor Antagonists; D058908:Adenosine A2 Receptor Agonists; D058917:Adenosine A2 Receptor Antagonists; D043682:Receptor, Adenosine A1; D043705:Receptor, Adenosine A2A; D014970:Xanthines; D019830:Adenosine-5'-(N-ethylcarboxamide); C051360:1,3-dipropyl-8-cyclopentylxanthine; D000242:Cyclic AMP; D000241:Adenosine