No description available.

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Spleen tyrosine kinase (Syk) plays a critical role in regulation of immune and inflammatory responses. This thesis investigated the role of Syk in the development of the asthma phenotype in acute and chronic mouse models of allergic airways inflammation. Airway hyperresponsiveness (AHR) to methacholine and inflammation increased significantly in HDM-induced compared with the saline control mice. We demonstrated that in vivo inhibition of Syk by selective Syk inhibitors, and genetic deletion of Syk using conditional Syk knockout mice attenuated AHR despite of inflammatory cell influx in the lung. Histological analysis showed airway remodeling in the chronic model, which was attenuated to some degree by deletion of Syk. This study identified a role of Syk in airway hyperresponsiveness and remodeling without significantly affecting leukocyte recruitment in HDM model of airways disease. My results support the improvement of therapeutic strategies in asthma by targeting the Syk pathway.

Spleen tyrosine kinase (Syk) plays a critical role in regulation of immune and inflammatory responses. This thesis investigated the role of Syk in the development of the asthma phenotype in acute and chronic mouse models of allergic airways inflammation. Airway hyperresponsiveness (AHR) to methacholine and inflammation increased significantly in HDM-induced compared with the saline control mice. We demonstrated that in vivo inhibition of Syk by selective Syk inhibitors, and genetic deletion of Syk using conditional Syk knockout mice attenuated AHR despite of inflammatory cell influx in the lung. Histological analysis showed airway remodeling in the chronic model, which was attenuated to some degree by deletion of Syk. This study identified a role of Syk in airway hyperresponsiveness and remodeling without significantly affecting leukocyte recruitment in HDM model of airways disease. My results support the improvement of therapeutic strategies in asthma by targeting the Syk pathway.

β-(1,3)-Glucan is present in mould cell walls and frequently detected in house dust mite (HDM) faeces. β-Glucan exposure is thought to be associated with pulmonary allergic inflammation in mouse and man, although the published data are inconsistent. Here, we show that highly purified β-glucan exacerbates HDM-induced eosinophilic, T helper 2 type airway responses by acting as an adjuvant, promoting activation, proliferation and polarisation of HDM-specific T cells (1-Derβ T cells). We therefore provide definitive evidence that β-glucan can influence allergic pulmonary inflammation.

No description available.

No description available.

Isolation and identification of all yeast species found on skin affected by atopic dermatitis, evaluation of their influence to the synthesis of IgE antibodies, and assessment of the possible cross-reactivity between different yeast species was performed. It was shown that in 36.9 % of the cases of atopic dermatitis, the affected skin was colonized with yeast belonging to three genera: Candida, Malassezia and Rhodotorula. Systematic and phylogenetic analysis of sequences from atypical Malassezia restricta strain M8 indicated that this isolate could be a member of a new yeast species. Three atypical Malassezia isolates M47, M54 and M235 were identified as non-lipid-dependent variants of Malassezia furfur. It was shown that in atopic dermatitis, cutaneous colonization with yeast is two-fold higher in adults than in children. The sera of atopic dermatitis patients have specific IgE antibodies to cross-reactive intracellular yeast antigens. Candida pelliculosa and house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae might share some allergenic epitopes. The results of this study suggest that attention should be given to a cutaneous colonization by saprophytic yeast since the immune response to the allergens could further exacerbate allergic inflammation due to cross-reactive epitopes. / Išskirtos ir identifikuotos atopinio dermatito pažeistą odą kolonizuojančios mielių rūšys, įvertinta jų įtaka specifinių IgE antikūnų sintezei bei kryžminių reakcijų tarp skirtingų mielių rūšių galimybė. Nustatyta, kad 36,9 % atvejų atopinio dermatito pažeista oda yra kolonizuojama Candida, Malassezia ir Rhodotorula genties mielėmis. Išskirtas netipinėmis fiziologinėmis savybėmis pasižymintis Malassezia restricta kamienas M8 gali būti naujos rūšies atstovas. Išskirti netipinėmis fiziologinėmis savybėmis pasižymintys Malassezia genties kamienai M47, M54 ir M235 identifikuoti kaip nuo išorinio lipidų šaltinio nepriklausantys Malassezia furfur. Įrodyta, kad mielės suaugusių asmenų atopinio dermatito pažeistą odą kolonizuoja du kartus dažniau negu vaikų. Įrodyta, kad atopiniu dermatitu sergančių asmenų kraujo serume aptinkama prieš kryžmiškai reaguojančius mielių viduląstelinius antigenus nukreiptų specifinių IgE antikūnų. Taip pat nustatyta, kad Candida pelliculosa ir namų dulkių erkių Dermatophagoides pteronyssinus ir Dermatophagoides farinae alergenai gali turėti panašius epitopus. Darbo rezultatai patikimai rodo, kad atopinio dermatito pažeistą odą kolonizuojančios komensalinės mielės gali pasunkinti atopinio dermatito eigą dėl kryžmiškai reaguojančių epitopų tarp skirtingų biologinių rūšių antigenų.

One of the purposes of allergen-specific immunotherapy (SIT) is to modulate the humoral immune response against allergens with significant increases in allergen-specific IgG1 and IgG4 levels. These antibodies are associated with blocking activity by preventing IgE binding to allergen and leading to reduced inflammatory responses. This study aimed to investigate in vitro blocking activity of allergen-specific IgG antibodies on IgE reactivity to D. pteronyssinus (Dpt) in sera from atopic patients. Dpt-specific IgG antibodies were obtained from atopic sera and irrelevant IgG from non-atopic sera. IgG antibodies were purified by ammonium sulfate precipitation followed by Protein-G affinity chromatography and evaluated with regards to purity by SDS-PAGE and immunoreactivity by slot-blot and immunoblot assays. The blocking activity was evaluated by inhibition ELISA. The electrophoretical profile after salting-out precipitation showed an enrichment of high molecular weight proteins in the precipitated fraction and strongly stained bands in the ligand fraction after chromatography, compatible with molecular weight of human IgG. It was detected strong immunoreactivity to IgG, negligible to IgA, and no reactivity to IgE and IgM. Dpt-specific IgG fraction was capable to significantly reduce levels of IgE anti-Dpt, resulting in 35-51% inhibition of IgE reactivity to Dpt in atopic patient sera. Allergen-specific IgG antibodies purified using available and standardized methodology are able to inhibit IgE reactivity to Dpt allergen extract. In addition to the clinical symptoms improvement (subjective parameter), this approach reinforces that the intermittent measurement of serum allergen-specific IgG antibodies will be an important objective laboratorial parameter that will help specialists to follow their patients under SIT. / Uma das propostas da imunoterapia alérgeno específica é a de modular a resposta imune humoral contra alérgenos, com aumento significativo nos níveis de IgG1 e IgG4 específicos. Esses anticorpos estão associados com uma atividade bloqueadora, impedindo a ligação de anticorpos IgE ao alérgeno e levando a uma redução nas respostas inflamatórias. Esse estudo objetivou investigar a atividade bloqueadora, in vitro, de anticorpos IgG específicos sobre a reatividade de IgE a D. pteronyssinus (Dpt) em soros de pacientes atópicos. Anticorpos IgG específicos foram obtidos de soros de pacientes atópicos, e IgG irrelevante a partir de soros de não atópicos, e depois purificados por precipitação com sulfato de amônio, seguido de cromatografia de afinidade em Proteina G-agarose. A pureza desses anticorpos foi avaliada por SDS-PAGE, a imunoreatividade por ensaios de slot-blot e immunoblot, e a atividade bloqueadora por ELISA inibição. O perfil eletroforético, após precipitação com sulfato de amônio, mostrou um enriquecimento de proteínas de alto peso molecular na fração precipitada,e bandas fortemente coradas na fração ligante após a cromatografia, compatíveis com o peso molecular de IgG humana. Foi detectada uma forte imunoreatividade para IgG, leve para IgA, e nenhuma reatividade para IgE e IgM. A Fração IgG específica foi capaz de reduzir significantemente os níveis de IgE anti-Dpt, resultando em 35-51% de inibição da reatividade de IgE a Dpt em pools de soros de pacientes atópicos. Anticorpos IgG específicos purificados, através de uma metodologia disponível e padronizada, são capazes de inibir a reatividade de IgE ao extrato alergênico Dpt. Além da melhoria da sintomatologia clínica, considerada um parâmetro subjetivo, essa abordagem reforça que a avaliação intermitente de anticorpos IgG alérgeno-específicos pode ser uma ferramenta importante, auxiliando especialistas a acompanharem seus pacientes em processo de imunoterapia específica. / Mestre em Ciências da Saúde