Th17 Cells Provide Mucosal Protection against Gastric Trypanosoma cruzi Infection

Oral Infection and Survival of Trypanosoma cruzi in Sugarcane Juice Conditioned at Different Temperatures

PURPOSE

The current most important form of transmission for Trypanosoma cruzi is the oral route, being responsible for high mortality during the acute phase in infected individuals. Thus, this study aimed to investigate the possibility of infection for this parasite using sugarcane juice in different temperatures employing metacyclic trypomastigotes obtained from xenodiagnosis performed in Swiss mice previously infected with T.cruzi Y strain, and then diluted in sugarcane juice.

METHODS

For stomach histopathological analysis, 20 mice were infected with metacyclic trypomastigotes diluted in sugarcane juice and euthanized after the 2nd, 4th, 10th, and 15th days after infection. Concurrently, six batches of ten mice were fed using 1.5 mL of the mixture and kept for 12 h at the temperatures of - 80 ºC, - 20 ºC, + 2 ºC, + 28 ºC, + 60 ºC, and + 80 ºC, for later infection verification.

RESULTS

Inflammatory infiltrate was found after the 2nd day of infection, and amastigotes nests were present after the 4th, 10th, and 15th day in the margo plicatus stomach region. Viable trypomastigotes were observed in the microtubes kept at - 80 ºC, - 20 ºC, and + 2 ºC, but the animal's infection was observed in the - 80 ºC and + 2 ºC groups. In vitro tests demonstrated the decrease of T. cruzi trypomastigote viability, which was negative after 120 h at -20 ºC and 144 h at + 2 ºC, in contrast to the maintenance of survival after 168 h at - 80 ºC.

CONCLUSION

We observed the ability of survival and infection of T. cruzi packaged at - 80 ºC without the use of preservatives and, therefore, less suitable for storing food.

Recombinant antigen P29 of Echinococcus granulosus induces Th1, Tc1, and Th17 cell immune responses in sheep

Echinococcosis is a common human and animal parasitic disease that seriously endangers human health and animal husbandry. Although studies have been conducted on vaccines for echinococcosis, to date, there is no human vaccine available for use. One of the main reasons for this is the lack of in-depth research on basic immunization with vaccines. Our previous results confirmed that recombinant antigen P29 (rEg.P29) induced more than 90% immune protection in both mice and sheep, but data on its induction of sheep-associated cellular immune responses are lacking. In this study, we investigated the changes in CD4+ T cells, CD8+ T cells, and antigen-specific cytokines IFN-γ, IL-4, and IL-17A after rEg.P29 immunization using enzyme-linked immunospot assay (ELISPOT), enzyme-linked immunosorbent assay (ELISA), and flow cytometry to investigate the cellular immune response induced by rEg.P29 in sheep. It was found that rEg.P29 immunization did not affect the percentage of CD4+ and CD8+ T cells in peripheral blood mononuclear cells (PBMCs), and was able to stimulate the proliferation of CD4+ and CD8+ T cells after immunization in vitro. Importantly, the results of both ELISPOT and ELISA showed that rEg.P29 can induce the production of the specific cytokines IFN-γ and IL-17A, and flow cytometry verified that rEg.P29 can induce the expression of IFN-γ in CD4+ and CD8+ T cells and IL-17A in CD4+ T cells; however, no IL-4 expression was observed. These results indicate that rEg.P29 can induce Th1, Th17, and Tc1 cellular immune responses in sheep against echinococcosis infection, providing theoretical support for the translation of rEg.P29 vaccine applications.

Macrophages in immunoregulation and therapeutics

Macrophages exist in various tissues, several body cavities, and around mucosal surfaces and are a vital part of the innate immune system for host defense against many pathogens and cancers. Macrophages possess binary M1/M2 macrophage polarization settings, which perform a central role in an array of immune tasks via intrinsic signal cascades and, therefore, must be precisely regulated. Many crucial questions about macrophage signaling and immune modulation are yet to be uncovered. In addition, the clinical importance of tumor-associated macrophages is becoming more widely recognized as significant progress has been made in understanding their biology. Moreover, they are an integral part of the tumor microenvironment, playing a part in the regulation of a wide variety of processes including angiogenesis, extracellular matrix transformation, cancer cell proliferation, metastasis, immunosuppression, and resistance to chemotherapeutic and checkpoint blockade immunotherapies. Herein, we discuss immune regulation in macrophage polarization and signaling, mechanical stresses and modulation, metabolic signaling pathways, mitochondrial and transcriptional, and epigenetic regulation. Furthermore, we have broadly extended the understanding of macrophages in extracellular traps and the essential roles of autophagy and aging in regulating macrophage functions. Moreover, we discussed recent advances in macrophages-mediated immune regulation of autoimmune diseases and tumorigenesis. Lastly, we discussed targeted macrophage therapy to portray prospective targets for therapeutic strategies in health and diseases.

Aging-Related Mechanisms Contribute to Corticosteroid Insensitivity in Elderly Asthma

Asthma in elderly populations is an increasing health problem that is accompanied by diminished lung function and frequent exacerbations. As potent anti-inflammatory drugs, corticosteroids are commonly used to reduce lung inflammation, improve lung function, and manage disease symptoms in asthma. Although effective for most individuals, older patients are more insensitive to corticosteroids, making it difficult to manage asthma in this population. With the number of individuals older than 65 continuing to increase, it is important to understand the distinct mechanisms that promote corticosteroid insensitivity in the aging lung. In this review, we discuss corticosteroid insensitivity in asthma with an emphasis on mechanisms that contribute to persistent inflammation and diminished lung function in older individuals.