Robust Phenotypic Activation of Eosinophils during Experimental Infection.

Eosinophils are multifunctional cells that have cytotoxic proinflammatory activities and stimulate CD4 T-cells in experimental models of allergy and parasitic infections. Eosinophils, when exposed to antigens, are activated, expressing the CD38/CD69 molecules and exhibited increased expression of major histocompatibility complex (MHC-II), CD80 and CD86, suggesting they play a role upon antigen stimulation. In the present study, we evaluated the profile of eosinophils using conventional and image flow cytometry upon experimental infection. antigens induced a robust activation on this subset, contributing to the immune responses elicited in the experimental model for associated visceral larva migrans syndrome. Data analysis demonstrated that, during murine infection, eosinophils from peripheral blood, spleen, and bone marrow presented upregulated expression of CD69/MHC-II/CD80/CD86. As opposed to splenic and bone marrow eosinophils, circulating eosinophils had increased expression of activation markers upon infection. The enhanced connectivity between eosinophils and T-cells in -infected mice in all three compartments (peripheral blood, spleen, and bone marrow) also supports the hypothesis that eosinophils may adopt a role during infection. Moreover, antigen stimulation resulted in activation and upregulation of co-stimulatory-related molecules by bone marrow-derived eosinophils. Our findings are evidence of activation and upregulation of important activation and co-stimulatory-related molecules in eosinophils and suggest a reshape of activation hierarchy toward eosinophils during experimental infection.