Robust Phenotypic Activation of Eosinophils during Experimental Toxocara canis 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 Toxocara canis antigen stimulation. In the present study, we evaluated the profile of eosinophils using conventional and image flow cytometry upon experimental T. canis infection. T. canis antigens induced a robust activation on this subset, contributing to the immune responses elicited in the experimental model for T. canis-associated visceral larva migrans syndrome. Data analysis demonstrated that, during murine T. canis 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 T. canis infection. The enhanced connectivity between eosinophils and T-cells in T. canis-infected mice in all three compartments (peripheral blood, spleen, and bone marrow) also supports the hypothesis that eosinophils may adopt a role during T. canis infection. Moreover, in vitro T. canis 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 T. canis infection.

Efeito de bioterápico na eosinofilia durante a SLMV experimental / Biotherapic effect in eosinophilia during experimental VLMS

O Toxocara canis (Tc) é um parasito pertencente ao filo Nematódeo que possui como hospedeiro definitivo os cães, O homem é hospedeiro paratênico e contamina-se acidentalmente ao ingerir ovos contendo larvas infectantes (L3) do parasito, as quais são liberadas e atravessam a mucosa intestinal, atingem a circulação, Durante este processo migratório, antígenos de excreção e secreção (TES) são liberados provocando intensa reação inflamatória, do tipo Th2, caracterizando a síndrome, denominada Larva Migrans Visceral (SLMV), As principais características desta doença crônica são as eosinofilias sanguínea e tecidual persistentes, Desse modo, torna-se importante a busca por terapias que contribuam com a redução dos quadros inflamatórios com intensa eosinofilia, Assim, o uso deste bioterápico, produzido a partir do extrato antigênico de ovos e larvas de (Tc), e seu efeito no recrutamento de leucócitos totais, células mononucleares e eosinófilos no sangue, para o espaço broncoalveolar e para a cavidade peritoneal de camundongos infectados pelo (Tc) foi investigado, Foram utilizados camundongos fêmeas (Swiss), divididos nos grupos: Controle (C), Infectado (Tc), Imunizado (Im+Tc) e Tratado (Tc+Bio), Os animais Tc, Im+Tc e Tc+Bio receberam 500 ovos/animal por gavagem, Posteriormente, os animais foram eutanasiados no 18º dia da infecção e o número das células nos compartimentos foi determinado, Os resultados obtidos demonstraram que, Im+Tc, assim como nos Tc+Bio tiveram redução significativa dessas células nos compartimentos analisados quando comparados grupo Tc, Assim, sugeriu-se que a bioterapia modulou negativamente o recrutamento de células inflamatórias, principalmente eosinófilos no sangue, pulmão e intestino demonstrando um potencial anti-inflamatório desse bioterápico na SLMV experimental...

The Toxocara canis (Tc) is a parasite that belongs to the nematode phylum and has dogs as definitive host. The men can be accidentally contaminated by ingesting eggs containing infective larvae of the parasite. These larvae, when ingested, pass through the intestinal mucosa, reach the portal circulation and migrate through different tissues of the host. During this process, excretory-secretory antigens (TES) are released causing an intense inflammatory reaction, the Th2 type, characterizing the syndrome, called Visceral Larva migrans (VLMS). The main features of this chronic disease are blood and tissue eosinophilias. Thus, it is important to search for therapies that may contribute to the reduction of inflammatory conditions with intense eosinophilia. In this study, we investigated the use of a biotherapic produced from the antigenic extract from eggs and larvae (Tc) and its effect on the recruitment of total leukocyte, mononuclear cells and eosinophils in blood, bronchoalveolar space and peritoneal cavity of mice infected with (Tc). Female mice (Swiss) were used divided in three groups: control (C), Infected (Tc) Immunized (Im + Tc) and Treaty (Tc + Bio). The animals Tc, Im + Tc and Tc + Bio received 500 eggs / animal by gavage. Subsequently, the animals were euthanized on day 18 after infection and the number of cells in the compartments was determined. Our results showed that, Im + Tc, as in Tc + Bio had reduced these cells in compartments analyzed compared to Tc group. Thus, it was suggested that the biotherapy negatively modulated the recruitment of inflammatory cells, particularly eosinophils in blood, lung and intestine demonstrating an anti-inflammatory potential of the biotherapic in the experimental VLMS...