We evaluated the role of IL-18 during Leishmania amazonensis infection in C57BL/6 mice, using IL-18KO mice. We showed that IL-18 is involved in susceptibility to L. amazonensis, since IL-18KO mice presented reduced lesions and parasite loads. Because macrophages are the host cells of the parasite, we investigated if macrophages were involved in IL-18-mediated susceptibility to L. amazonensis. We showed that macrophages obtained from WT or IL-18KO responded similarly to L. amazonensis infection. Moreover, we showed that C57BL/6 macrophages do not respond to IL-18, since they do not express IL-18R. Therefore, macrophages are not involved in IL-18-mediated susceptibility to L. amazonensis.

The teaching of the contents of Immunology, an area of biological sciences that aims to describe and establish the mechanisms of aggression, defense and integrity of living organisms, is present in educational levels ranging from basic to higher in the curricula of science and biology in Brazil. Here, our objective was to characterize the researches on the methodologies of science teaching that researchers in immunology have developed for classes and courses and have presented in the meetings of the Brazilian society of immunology (SBI) from 2010 to 2017. Our analysis pointed out an increase in the number of abstracts of education in immunology at all levels of Brazilian education (with predominance in higher education) and with several teaching methodologies. In conclusion, our analysis will contribute to the understanding of the profile of teaching in this area, as well as to point out its weaknesses and its assertive actions.

Neutrophil overstimulation plays a crucial role in tissue damage during severe infections. Neuraminidase (NEU)-mediated cleavage of surface sialic acid has been demonstrated to regulate leukocyte responses. Here, we report that antiviral NEU inhibitors constrain host NEU activity, surface sialic acid release, ROS production, and NETs released by microbial-activated human neutrophils. In vivo, treatment with Oseltamivir results in infection control and host survival in peritonitis and pneumonia models of sepsis. Single-cell RNA sequencing re-analysis of publicly data sets of respiratory tract samples from critical COVID-19 patients revealed an overexpression of NEU1 in infiltrated neutrophils. Moreover, Oseltamivir or Zanamivir treatment of whole blood cells from severe COVID-19 patients reduces host NEU-mediated shedding of cell surface sialic acid and neutrophil overactivation. These findings suggest that neuraminidase inhibitors can serve as host-directed interventions to dampen neutrophil dysfunction in severe infections.

Leishmania major-infected TNF receptor 1 deficient (TNFR1 KO) mice resolve parasitism but fail to resolve lesions, while wild-type mice completely heal. We investigated the cell composition, cytokine production, and apoptosis in lesions from L. major-infected TNFR1 KO and wild-type (WT) mice. Chronic lesions from L. major-infected TNFR1 KO mice presented larger number of CD8+ T and Ly6G+ cells. In addition, higher concentrations of mRNA for IFN-γ CCL2 and CCL5, as well as protein, but lower numbers of apoptotic cells, were found in lesions from TNFR1 KO mice than in WT, at late time points of infection. Our studies showed that persistent lesions in L. major-infected TNFR1 KO mice may be mediated by continuous migration of cells to the site of inflammation due to the presence of chemokines and also by lower levels of apoptosis. We suggest that this model has some striking similarities to the mucocutaneous clinical form of leishmaniasis.

This article examines student engagement in an inquiry‐based learning activity, planned to provide students with elements in the social, epistemic, and conceptual dimensions related to the scientific practice in immunology. The activity was applied to 39 groups of students enrolled in immunology or biochemistry courses in a public university in Brazil. Students performed data‐collection through the execution of an in vitro assay. We analyzed how students represent data and use them to support their claims in their written constructs. To clarify which are the productive epistemologies in students' reports, we developed a framework for epistemic practice analysis. Our findings point to a pattern of several epistemic practice categories in their written text, mostly related to the particular contingences of data analysis, rather than to theoretical concepts. In addition, we observed that students performed literary inscriptions to represent their data; however, they tended not to cite all data obtained in their written texts. These results suggest that immunology education strategies should provide students with approaches that explore the role of data representation in the scientific text rhetoric. © 2019 International Union of Biochemistry and Molecular Biology, 47(6):672–680, 2019.

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Background and Purpose Neutrophil overstimulation plays a crucial role in tissue damage during severe infections. Because pathogen‐derived neuraminidase (NEU) stimulates neutrophils, we investigated whether host NEU can be targeted to regulate the neutrophil dysregulation observed in severe infections. Experimental Approach The effects of NEU inhibitors on lipopolysaccharide (LPS)‐stimulated neutrophils from healthy donors or COVID‐19 patients were determined by evaluating the shedding of surface sialic acids, cell activation, and reactive oxygen species (ROS) production. Re‐analysis of single‐cell RNA sequencing of respiratory tract samples from COVID‐19 patients also was carried out. The effects of oseltamivir on sepsis and betacoronavirus‐induced acute lung injury were evaluated in murine models. Key Results Oseltamivir and zanamivir constrained host NEU activity, surface sialic acid release, cell activation, and ROS production by LPS‐activated human neutrophils. Mechanistically, LPS increased the interaction of NEU1 with matrix metalloproteinase 9 (MMP‐9). Inhibition of MMP‐9 prevented LPS‐induced NEU activity and neutrophil response. In vivo, treatment with oseltamivir fine‐tuned neutrophil migration and improved infection control as well as host survival in peritonitis and pneumonia sepsis. NEU1 also is highly expressed in neutrophils from COVID‐19 patients, and treatment of whole‐blood samples from these patients with either oseltamivir or zanamivir reduced neutrophil overactivation. Oseltamivir treatment of intranasally infected mice with the mouse hepatitis coronavirus 3 (MHV‐3) decreased lung neutrophil infiltration, viral load, and tissue damage. Conclusion and Implications These findings suggest that interplay of NEU1–MMP‐9 induces neutrophil overactivation. In vivo, NEU may serve as a host‐directed target to dampen neutrophil dysfunction during severe infections.

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