Corrigendum: Immunization of Experimental Dogs With Salivary Proteins From Lutzomyia longipalpis, Using DNA and Recombinant Canarypox Virus Induces Immune Responses Consistent With Protection Against Leishmania infantum.

[This corrects the article DOI: 10.3389/fimmu.2018.02558.].

Immunization of Experimental Dogs With Salivary Proteins From Lutzomyia longipalpis, Using DNA and Recombinant Canarypox Virus Induces Immune Responses Consistent With Protection Against Leishmania infantum.

Metacyclic Leishmania promastigotes are transmitted by sand flies that inject parasites and saliva into the host's skin. Previous studies have demonstrated that DNA plasmids encoding Lutzomyia longipalpis salivary proteins LJM17 and LJL143, when used to immunize dogs, resulted in a systemic and local Th1 cell-mediated immunity that interfered in parasite survival in vitro. Here we evaluated the ability of these same salivary antigens to induce anti-Leishmania immunity and to confer protection by immunizing dogs using a novel vaccination strategy more suitable for use in the field. The strategy consisted of a single dose of plasmid followed by two doses of recombinant Canarypoxvirus (rCanarypoxvirus) expressing L. longipalpis salivary proteins (LJM17 or LJL143). Thirty days after the final immunization, dogs were intradermally challenged with 107Leishmania infantum promastigotes in the presence of L. longipalpis saliva. We followed the experimentally infected dogs for 10 months to characterize clinical, parasitological, and immunological parameters. Upon vaccination, all immunized dogs presented strong and specific humoral responses with increased serum concentrations of IFN-γ, TNF, IL-7, and IL-15. The serum of dogs immunized with LJM17 also exhibited high levels of IL-2, IL-6, and IL-18. L. infantum infection was established in all experimental groups as evidenced by the presence of anti-Leishmania IgG, and by parasite detection in the spleen and skin. Dogs immunized with LJM17-based vaccines presented higher circulating levels of IFN-γ, IL-2, IL-6, IL-7, IL-15, IL-18, TNF, CXCL10, and GM-CSF post-infection when compared with controls. Results demonstrated that relevant Leishmania-specific immune responses were induced following vaccination of dogs with L. longipalpis salivary antigen LJM17 administered in a single priming dose of plasmid DNA, followed by two booster doses of recombinant Canarypox vector. Importantly, a significant increase in pro-inflammatory cytokines and chemokines known to be relevant for protection against leishmaniasis was evidenced after challenging LJM17-vaccinated dogs as compared to controls. Although similar results were observed following immunization with LJL143, the pro-inflammatory response observed after immunization was attenuated following infection. Collectively, these data suggest that the LJM17-based vaccine induced an immune profile consistent with the expected protective immunity against canine leishmaniosis. These results clearly support the need for further evaluation of the LJM17 antigen, using a heterologous prime-boost vaccination strategy against canine visceral leishmaniosis (CVL).

Estudo da interação entre neutrófilos, células dendríticas humanas e L. braziliensis / Study of the interaction between neutrophils, human dendritic cells and L. braziliensis

Os neutrófilos são essenciais para a resposta imune inata contra uma variedade de patógenos. Eles são capazes de modular a resposta imune através da produção de citocinas e quimiocinas, degranulação e a sua interação direta com outras células no local da infecção, tais como as células dendríticas. A interação entre as células do sistema imune inato é essencial para direcionar a resposta imune adaptativa, a qual é responsável pela eliminação de microrganismos e manutenção de memória imunológica. Objetivo: Este estudo avaliou a interação de neutrófilos humanos com Leishmania braziliensis, através da análise da expressão de moléculas de superfície, liberação de enzimas presentes nos grânulos e produção de espécies reativas de oxigênio (ROS). Também foi avaliada a interação entre neutrófilos humanos infectados e células dendríticas, a fim de se observar o efeito desta interação na indução da ativação das células dendríticas. Metodologia: Os neutrófilos foram purificados a partir do sangue periférico de doadores saudáveis e as células dendríticas foram geradas in vitro. Os neutrófilos foram infectados ou não com L. braziliensis e co-cultivados com as células dendríticas. Em seguida, os sobrenadantes e as células foram coletadas para avaliar a liberação de enzimas, tais como mieloperoxidase (MPO) e metaloproteinase 9 (MMP-9). O fenótipo e a função dos neutrófilos foram analisados através da expressão de Mac-1 (CD18 e CD11b), CD16, CD62-L e produção de ROS...

Neutrophils are essential in the innate immune response against a variety of pathogens. They are able to modulate immune response by cytokine and chemokine production, release of granules and their direct interaction with other cells at the infection site. Dendritic cells are recruited in response to cytokines and chemokines produced by neutrophils. The interaction between cells of the innate immune system is essential for targeting the adaptive immune response, which is responsible for eliminating microorganisms and the maintenance of immunological memory. Objective: Evaluate the interaction of human neutrophils with Leishmania braziliensis, through the analysis of surface molecule expression, release of granules enzymes and production of reactive oxygen species (ROS). We also evaluated the interaction between human infected neutrophils and dendritic cells, in order to observe the effect of this interaction on dendritic cells. Methodology: Neutrophils were purified from peripheral blood of healthy donors and dendritic cells were generated in vitro. Neutrophils were infected or not with L. braziliensis and cocultured with DC. Afterwards, supernatants and cells were harvested to evaluate the release of granules enzymes, such as myeloperoxidase (MPO) and metalloproteinase 9 (MMP-9). Neutrophils phenotype and function were analyzed by the expression of Mac-1 (CD18 and CD11b), CD16 and ROS production...