Recombinant XXXX obsoletus complex allergens stimulate antigen-specific T cells of insect bite hypersensitive Shetland ponies in  vitro.

@entity56 @entity14197 @entity272
BACKGROUND: Ponies may suffer from @entity56 ( @entity56 ), an allergic IgE-mediated @entity272 , induced by allergens from @entity14197 of the @entity14197 spp. HYPOTHESIS/OBJECTIVES: To determine whether recombinant @entity14197 obsoletus allergens are able to activate T cells of ponies exposed to C.  obsoletus and whether these allergen-specific responses differ between @entity56 -affected and healthy ponies. ANIMALS: Ten @entity56 -affected Shetland ponies and 10 age-matched healthy controls taken from the same stables, to ensure similar exposure to midges. METHOD: Peripheral blood mononuclear cells (PBMC) were cultured with two different pools of recombinant C.  obsoletus complex allergens to expand the allergen-specific T cells. These PBMC cultures were subsequently co-cultured with mature dendritic cells (DCs) loaded with the same antigens. Induction of Th1, Th2 and regulatory T (Treg) cells in these DC/PBMC co-cultures was assessed by analysis of IFN-y, IL-4, IL-10 and FoxP3 expression levels using quantitative RT-PCR and phenotyping by flow cytometry. RESULTS: Recombinant C.  obsoletus allergens increased IFN-y mRNA expression levels, percentages of IFN-y expressing (Th1) cells and CD25(high) FoxP3(+) IL-10(+) Tregs compared to unstimulated DC/PBMC co-cultures. Stimulation of IL-4 expressing Th2 cells by the recombinant allergens was far less pronounced. The DC/PBMC co-cultures did not reveal significant differences between healthy and @entity56 -affected ponies for any of the analysed parameters, except for higher IL-4 mRNA levels in @entity56 affected ponies after stimulation with one of the two allergen pools. CONCLUSION AND CLINICAL IMPORTANCE: The recombinant C.  obsoletus complex allergens can stimulate antigen-specific Th1 and IL10 producing Treg cells and are therefore promising candidates for the immunotherapy of @entity56 .
