title: Impact of cAMP on the T-cell response to type II collagen.
abstract: There is considerable interest in the possible use of cAMP-elevating agents in the treatment of autoimmune diseases such as rheumatoid arthritis. The objective of this study was to evaluate the impact of different cAMP-elevating agents on the T-cell response to type II collagen within the context of collagen-induced arthritis, a murine model of rheumatoid arthritis. Spleen cells or lymph node cells from type-II-collagen-immunized DBA/1 mice were cultured in the presence of type II collagen plus one of five different cAMP-elevating agents: rolipram, forskolin, prostaglandin E2, 8-bromo-cAMP, or cholera toxin. Levels of interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and IL-5 were measured in culture supernatants by enzyme-linked immunosorbent assay. All of the cAMP-elevating agents tested were found to profoundly suppress IFN-gamma production in a dose-dependent manner. IL-4 and IL-5 production was slightly up-regulated at low concentrations of the cAMP-elevating agents and was modestly suppressed at the highest concentrations of cAMP-elevating agents. Experiments were then carried out to determine whether T cells were directly affected by cAMP-elevating agents or whether the immunomodulatory effects were mediated via antigen-presenting cells. Pulsing T cells alone for a brief period with cholera toxin produced an almost identical effect to pulsing antigen-presenting cells alone, i.e. down-regulation of proliferation, down-regulation of IFN-gamma production with little effect on IL-5 production. It was concluded that cAMP-elevating agents suppressed T helper type 1 responses to type II collagen to a greater extent than T helper type 2 responses. The cAMP-elevating agents could directly influence the activity of T cells but, in addition, influenced the ability of antigen-presenting cells to support T helper type 1 responses.
authors.affiliation: The Kennedy Institute of Rheumatology Division, Imperial College London, UK.
authors.forename: Patricia
authors.initials: P
authors.lastname: Ozegbe
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Foey
authors.forename: Salman
authors.initials: S
authors.lastname: Ahmed
authors.forename: Richard O
authors.initials: RO
authors.lastname: Williams
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D001169:Arthritis, Experimental / Q000188:drug therapy / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology*; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000627:therapeutic use; D005576:Colforsin / Q000627:therapeutic use; D024043:Collagen Type II / Q000276:immunology; D000242:Cyclic AMP / Q000378:metabolism*; D015232:Dinoprostone / Q000627:therapeutic use; D004789:Enzyme Activation; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D023421:Models, Animal; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use; D020889:Rolipram / Q000627:therapeutic use; D015290:Second Messenger Systems / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D024043:Collagen Type II; D015848:Interleukin-5; D010726:Phosphodiesterase Inhibitors; D005576:Colforsin; D015847:Interleukin-4; D015124:8-Bromo Cyclic Adenosine Monophosphate; D007371:Interferon-gamma; D002772:Cholera Toxin; D000242:Cyclic AMP; D020889:Rolipram; D015232:Dinoprostone