•Approach used here can be expanded to generate flu vaccine with universal relevance.•Identified T cell epitopes induced heterologous protection in HLA transgenic mice.•Conserved flu putative ...immunogenic sequences were identified via immunoinformatics.•Predicted HLA-A2 and pan-DR-restricted epitopes immunogenic in HLA-transgenic mice.•Predicted CD4 and CD8 epitopes induced effector function in human T cells.
Influenza world-wide causes significant morbidity and mortality annually, and more severe pandemics when novel strains evolve to which humans are immunologically naïve. Because of the high viral mutation rate, new vaccines must be generated based on the prevalence of circulating strains every year. New approaches to induce more broadly protective immunity are urgently needed. Previous research has demonstrated that influenza-specific T cells can provide broadly heterotypic protective immunity in both mice and humans, supporting the rationale for developing a T cell-targeted universal influenza vaccine. We used state-of-the art immunoinformatic tools to identify putative pan-HLA-DR and HLA-A2 supertype-restricted T cell epitopes highly conserved among > 50 widely diverse influenza A strains (representing hemagglutinin types 1, 2, 3, 5, 7 and 9). We found influenza peptides that are highly conserved across influenza subtypes that were also predicted to be class I epitopes restricted by HLA-A2. These peptides were found to be immunoreactive in HLA-A2 positive but not HLA-A2 negative individuals. Class II-restricted T cell epitopes that were highly conserved across influenza subtypes were identified. Human CD4+ T cells were reactive with these conserved CD4 epitopes, and epitope expanded T cells were responsive to both H1N1 and H3N2 viruses. Dendritic cell vaccines pulsed with conserved epitopes and DNA vaccines encoding these epitopes were developed and tested in HLA transgenic mice. These vaccines were highly immunogenic, and more importantly, vaccine-induced immunity was protective against both H1N1 and H3N2 influenza challenges. These results demonstrate proof-of-principle that conserved T cell epitopes expressed by widely diverse influenza strains can induce broadly protective, heterotypic influenza immunity, providing strong support for further development of universally relevant multi-epitope T cell-targeting influenza vaccines.
Zika virus (ZIKV) is a flavivirus primarily transmitted by
Aedes
species mosquitoes, first discovered in Africa in 1947, that disseminated through Southeast Asia and the Pacific Islands in the 2000s. ...The first ZIKV infections in the Americas were identified in 2014, and infections exploded through populations in Brazil and other countries in 2015/16. ZIKV infection during pregnancy can cause severe brain and eye defects in offspring, and infection in adults has been associated with higher risks of Guillain-Barré syndrome. We initiated a study to describe the natural history of Zika (the disease) and the immune response to infection, for which some results have been reported. In this paper, we identify ZIKV-specific CD4+ and CD8+ T cell epitopes that induce responses during infection. Two screening approaches were utilized: an untargeted approach with overlapping peptide arrays spanning the entire viral genome, and a targeted approach utilizing peptides predicted to bind human MHC molecules. Immunoinformatic tools were used to identify conserved MHC class I supertype binders and promiscuous class II binding peptide clusters predicted to bind 9 common class II alleles. T cell responses were evaluated in overnight IFN-γ ELISPOT assays. We found that MHC supertype binding predictions outperformed the bulk overlapping peptide approach. Diverse CD4+ T cell responses were observed in most ZIKV-infected participants, while responses to CD8+ T cell epitopes were more limited. Most individuals developed a robust T cell response against epitopes restricted to a single MHC class I supertype and only a single or few CD8+ T cell epitopes overall, suggesting a strong immunodominance phenomenon. Noteworthy is that many epitopes were commonly immunodominant across persons expressing the same class I supertype. Nearly all of the identified epitopes are unique to ZIKV and are not present in Dengue viruses. Collectively, we identified 31 immunogenic peptides restricted by the 6 major class I supertypes and 27 promiscuous class II epitopes. These sequences are highly relevant for design of T cell-targeted ZIKV vaccines and monitoring T cell responses to Zika virus infection and vaccination.
A controlled human infection model for assessing tuberculosis (TB) immunity can accelerate new vaccine development.
In this phase 1 dose escalation trial, 92 healthy adults received a single ...intradermal injection of 2 × 106 to 16 × 106 colony-forming units of Bacillus Calmette-Guérin (BCG). The primary endpoints were safety and BCG shedding as measured by quantitative polymerase chain reaction, colony-forming unit plating, and MGIT BACTEC culture.
Doses up to 8 × 106 were safe, and there was evidence for increased BCG shedding with dose escalation. The MGIT time-to-positivity assay was the most consistent and precise measure of shedding. Power analyses indicated that 10% differences in MGIT time to positivity (area under the curve) could be detected in small cohorts (n = 30). Potential biomarkers of mycobacterial immunity were identified that correlated with shedding. Transcriptomic analysis uncovered dose- and time-dependent effects of BCG challenge and identified a putative transcriptional TB protective signature. Furthermore, we identified immunologic and transcriptomal differences that could represent an immune component underlying the observed higher rate of TB disease incidence in males.
The safety, reactogenicity, and immunogenicity profiles indicate that this BCG human challenge model is feasible for assessing in vivo TB immunity and could facilitate the vaccine development process.
NCT01868464 (ClinicalTrials.gov).
Trypanosoma cruzi is the intracellular parasite of Chagas disease, a chronic condition characterized by cardiac and gastrointestinal morbidity. Protective immunity requires CD4
T cells, and Th1 cells ...and gamma interferon (IFN-γ) are important players in host defense. More recently, Th17 cells and interleukin 17A (IL-17A) have been shown to exert protective functions in systemic T. cruzi infection. However, it remains unclear whether Th17 cells and IL-17A protect in the mucosa, the initial site of parasite invasion in many human cases. We found that IL-17RA knockout (KO) mice are highly susceptible to orogastric infection, indicating an important function for this cytokine in mucosal immunity to T. cruzi. To investigate the specific role of Th17 cells for mucosal immunity, we reconstituted RAG1 KO mice with T. cruzi
specific T cell receptor transgenic Th17 cells prior to orogastric T. cruzi challenges. We found that Th17 cells provided protection against gastric mucosal T. cruzi infection, indicated by significantly lower stomach parasite burdens.
macrophage infection assays revealed that protection by Th17 cells is reduced with IL-17A neutralization or reversed by loss of macrophage NADPH oxidase activity. Consistently with this, mice lacking functional NADPH oxidase were not protected by Th17 cell transfer. These data are the first report that Th17 cells protect against mucosal T. cruzi infection and identify a novel protective mechanism involving the induction of NADPH oxidase activity by IL-17A. These studies provide important insights for Chagas vaccine development and, more broadly, increase our understanding of the diverse roles of Th17 cells in host defense.
The rate-limiting step of azo dye decolorization was elucidated by exploring the microbial reduction of a model quinone and the chemical decolorization by previously reduced quinone at different ...salinity conditions (2–8%). Microbial experiments were performed in batch with a marine consortium. The decolorization of Direct Blue 71 (DB71) by the marine consortium at 2% salinity, mediated with anthraquinone-2,6-disulfonate (AQDS), showed the highest rate of decolorization as compared with those obtained with riboflavin, and two samples of humic acids. Moreover, the incubations at different salinity conditions (0–8%) performed with AQDS showed that the highest rate of decolorization of DB71 by the marine consortium occurred at 2% and 4% salinity. In addition, the highest microbial reduction rate of AQDS occurred in incubations at 0%, 2%, and 4% of salinity. The chemical reduction of DB71 by reduced AQDS occurred in two stages and proceeded faster at 4% and 6% salinity. The results indicate that the rate-limiting step during azo decolorization was the microbial reduction of AQDS.
Display omitted
•A marine consortium uses humic substances as redox mediators for azo dye treatment.•Azo dye reduction was evaluated at different salt conditions using redox mediators.•The rate limiting step of azo dye reduction is the microbial reduction of AQDS.
Abstract only
ADP‐ribosylation factor‐domain protein 1 (ARD1/TRIM23) is a 64‐kDa multi‐functional protein containing an N‐terminal E3 ubiquitin ligase sequence, a C‐terminal GTPase (ADP‐ribosylation ...factor, ARF) domain, and an internal GTPase‐activating region. ARD1 has been implicated in the regulation of innate immunity, as well as the internalization and degradation of growth factor receptors, but biological functions associated with its intracellular localization in lysosomes and Golgi, remain unknown. Therefore, we compared the lysosomal proteome of livers from ARD1‐null (KO) and control mice. Lysosome‐associated membrane proteins (LAMPs) 1, 2, and 3 were significantly more abundant in the livers of KO mice than those of wild‐type (WT) mice. Levels of LAMP2 in mouse embryonic fibroblasts (MEFs) from ARD1‐KO mice were also higher than those from WT mice. Electron microscopic analysis of mouse liver revealed a larger number of primary and secondary lysosomes in KO than WT mice. In addition, the mean sizes of the primary and secondary lysosomes appeared smaller in KO liver samples than in WT. These findings suggest that ARD1 may have a role in lysosome function and warrant further investigation of ARD1 participation in lysosome biogenesis and/or autophagy.
PDF
