FURTHER ANALISYS OF THE PREVENTION OF ATOPIC DERMATITIS BY Toxoplasma gondii CHRONIC INFECTION

MATÍAS DAMIÁN PERRONE SIBILIA, MARÍA DE LOS ÁNGELES ALDIRICO, ARIADNA SOTO, MARIANO SERGIO PICCHIO, VANESA ROXANA SÁNCHEZ, NADIA ARCÓN, FLORENCIA MAGALÍ GIORGIO, VALENTINA MARTÍN, VAZULLI SILVIA, IGNACIO MARTÍN FENOY, ALEJANDRA GOLDMAN

buenos aires

Simposio; Reunión Conjunta sociedades biociencias; 2017

We previously showed that T. gondii infection diminishes the susceptibility todevelop experimental asthma. Afterwards we extended these results andshowed that the parasite can also modulate an atopic dermatitis. Skinhistopathology of mice infected before allergic sensitization was similar tonormal mice. This result correlated with diminished IgE and IgG1 levels andreduced OVA specific Th1/Th2 systemic cytokines. The aim of the present workwas to further study the mechanisms involved in this immunomodulatory effect.Adult BALB/c mice were orally infected with T. gondii cysts and, one monthlater, epicutaneously sensitized with OVA (TDA). Treatment was repeatedtwice, with a 2-week resting period between each sensitization. Controlsincluded non-infected mice sensitized with OVA (DA) or PBS (N) and infectedmice treated with PBS (T). Local IL-4, IL-5 and IFN- secretion was analysed inskin explants stimulated with OVA. T. gondii infection before allergicsensitization induced a local reduction in both IL-4 and IL-5 (p≤0.05) and a trendto decrease in IFN- levels compared to DA mice. The reduction in bothTh1/Th2 cytokines suggested that regulatory cells induced by the parasite mayaccount for the immunomodulatory effect. Hence, IL-10 and TGF-β supernatantlevels were evaluated after ex vivo stimulation of splenocytes with OVA andchanges in regulatory T cells CD4+Foxp3+ in spleen were measured by flowcytometry. No significant differences were observed in either TGF-β orCD4+Foxp3+ T cells between all experimental groups. On the other hand, whilea significant increase in IL-10 levels was obtained for the DA group compared tonon-sensitized mice; infection with the parasite restored IL-10 levels in TDAgroup. Altogether, these results show that T. gondii infection reduces both skinand systemic Th1/Th2 responses and suggest that Tregs cells would not beinvolved in the immunomodulatory effect.