FURTHER ANALISYS OF THE PREVENTION OF ATOPIC DERMATITIS BY TOXOPLASMA GONDII CHRONIC INFECTION

MATIAS PERRONE SIBILIA, MARÍA DE LOS ANGELES ALDIRICO, ARIADNA SOTO, MARIANO PICCHIO, VANESA ROXANA SÁNCHEZ, NADIA ARCON, FLORENCIA MAGALÍ GIORGIO; VALENTINA MARTIN; SILVIA VANZULLI, IGNACIO MARTÍN FENOY, ALEJANDRA GOLDMAN

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

We previously showed that T. gondii infection diminishes the susceptibilityto develop experimental asthma. Afterwards we extendedthese results and showed that the parasite can also modulate anatopic dermatitis. Skin histopathology of mice infected before allergicsensitization was similar to normal mice. This result correlatedwith diminished IgE and IgG1 levels and reduced OVA specific Th1/Th2 systemic cytokines. The aim of the present work was to furtherstudy the mechanisms involved in this immunomodulatory effect.Adult BALB/c mice were orally infected with T. gondii cysts and,one month later, epicutaneously sensitized with OVA (TDA). Treatmentwas repeated twice, with a 2-week resting period betweeneach sensitization. Controls included non-infected mice sensitizedwith OVA (DA) or PBS (N) and infected mice treated with PBS (T).Local IL-4, IL-5 and IFN-g secretion was analysed in skin explantsstimulated with OVA. T. gondii infection before allergic sensitizationinduced a local reduction in both IL-4 and IL-5 (p≤0.05) and a trendto decrease in IFN-g levels compared to DA mice. The reduction inboth Th1/Th2 cytokines suggested that regulatory cells induced bythe parasite may account for the immunomodulatory effect. Hence,IL-10 and TGF-β supernatant levels were evaluated after ex vivostimulation of splenocytes with OVA and changes in regulatory Tcells CD4+Foxp3+ in spleen were measured by flow cytometry.No significant differences were observed in either TGF-β or CD4+-Foxp3+ T cells between all experimental groups. On the other hand,while a significant increase in IL-10 levels was obtained for the DAgroup compared to non-sensitized mice; infection with the parasiterestored IL-10 levels in TDA group. Altogether, these results showthat T. gondii infection reduces both skin and systemic Th1/Th2 responsesand suggest that Tregs cells would not be involved in theimmunomodulatory effect.