Cryptosporidium Priming Is More Effective than Vaccine for Protection against Cryptosporidiosis in a Murine Protein Malnutrition Model

Cryptosporidium is a major cause of severe diarrhea, especially in malnourished children. Using a murine model of C. parvum oocyst challenge that recapitulates clinical features of severe cryptosporidiosis during malnutrition, we interrogated the effect of protein malnutrition (PM) on primary and secondary responses to C. parvum challenge, and tested the differential ability of mucosal priming strategies to overcome the PM-induced susceptibility. We determined that while PM fundamentally alters systemic and mucosal primary immune responses to Cryptosporidium, priming with C. parvum (106 oocysts) provides robust protective immunity against re-challenge despite ongoing PM. C. parvum priming restores mucosal Th1-type effectors (CD3+CD8+CD103+ T-cells) and cytokines (IFNγ, and IL12p40) that otherwise decrease with ongoing PM. Vaccination strategies with Cryptosporidium antigens expressed in the S. Typhi vector 908htr, however, do not enhance Th1-type responses to C. parvum challenge during PM, even though vaccination strongly boosts immunity in challenged fully nourished hosts. Remote non-specific exposures to the attenuated S. Typhi vector alone or the TLR9 agonist CpG ODN-1668 can partially attenuate C. parvum severity during PM, but neither as effectively as viable C. parvum priming. We conclude that although PM interferes with basal and vaccine-boosted immune responses to C. parvum, sustained reductions in disease severity are possible through mucosal activators of host defenses, and specifically C. parvum priming can elicit impressively robust Th1-type protective immunity despite ongoing protein malnutrition. These findings add insight into potential correlates of Cryptosporidium immunity and future vaccine strategies in malnourished children

RNA delivery by extracellular vesicles in mammalian cells and its applications.

The term 'extracellular vesicles' refers to a heterogeneous population of vesicular bodies of cellular origin that derive either from the endosomal compartment (exosomes) or as a result of shedding from the plasma membrane (microvesicles, oncosomes and apoptotic bodies). Extracellular vesicles carry a variety of cargo, including RNAs, proteins, lipids and DNA, which can be taken up by other cells, both in the direct vicinity of the source cell and at distant sites in the body via biofluids, and elicit a variety of phenotypic responses. Owing to their unique biology and roles in cell-cell communication, extracellular vesicles have attracted strong interest, which is further enhanced by their potential clinical utility. Because extracellular vesicles derive their cargo from the contents of the cells that produce them, they are attractive sources of biomarkers for a variety of diseases. Furthermore, studies demonstrating phenotypic effects of specific extracellular vesicle-associated cargo on target cells have stoked interest in extracellular vesicles as therapeutic vehicles. There is particularly strong evidence that the RNA cargo of extracellular vesicles can alter recipient cell gene expression and function. During the past decade, extracellular vesicles and their RNA cargo have become better defined, but many aspects of extracellular vesicle biology remain to be elucidated. These include selective cargo loading resulting in substantial differences between the composition of extracellular vesicles and source cells; heterogeneity in extracellular vesicle size and composition; and undefined mechanisms for the uptake of extracellular vesicles into recipient cells and the fates of their cargo. Further progress in unravelling the basic mechanisms of extracellular vesicle biogenesis, transport, and cargo delivery and function is needed for successful clinical implementation. This Review focuses on the current state of knowledge pertaining to packaging, transport and function of RNAs in extracellular vesicles and outlines the progress made thus far towards their clinical applications

A new phylogenetic tribal classification of the grape family (Vitaceae)

Vitaceae (the grape family) consist of 16 genera and ca. 950 species primarily distributed in tropical regions. The family is well-known for the economic importance of grapes, and is also ecologically significant with many species as dominant climbers in tropical and temperate forests. Recent phylogenetic and phylogenomic analyses of sequence data from all three genomes have supported five major clades within Vitaceae: (i) the clade of Ampelopsis, Nekemias, Rhoicissus, and Clematicissus; (ii) the Cissus clade; (iii) the clade of Cayratia, Causonis, Cyphostemma, Pseudocayratia, Tetrastigma, and an undescribed genus Afrocayratia; (iv) the clade of Parthenocissus and Yua; and (v) the grape genus Vitis and its close tropical relatives Ampelocissus, Pterisanthes and Nothocissus, with Nothocissus and Pterisanthes nested within Ampelocissus. Based on the phylogenetic and morphological (mostly inflorescence, floral and seed characters) evidence, the new classification places the 950 species and 16 genera into five tribes: (i) tribe Ampelopsideae J.Wen & Z.L.Nie, trib. nov. (47 species in four genera; Ampelopsis, Nekemias, Rhoicissus and Clematicissus); (ii) tribe Cisseae Rchb. (300 species in one genus; Cissus); (iii) tribe Cayratieae J.Wen & L.M.Lu, trib. nov. (370 species in seven genera; Cayratia, Causonis, Afrocayratia, Pseudocayratia, Acareosperma, Cyphostemma and Tetrastigma); (iv) tribe Parthenocisseae J.Wen & Z.D.Chen, trib. nov. (ca. 16 spp. in two genera; Parthenocissus and Yua); and (v) tribe Viteae Dumort. (ca. 190 species in two genera; Ampelocissus and Vitis)

Down-regulation of epithelial IL-8 responses in Helicobacter pylori-infected duodenal ulcer patients depends on host factors, rather than bacterial factors

Helicobacter pylori infection is one of the most common gastrointestinal infections worldwide. Although the majority of the infected individuals remain asymptomatic carriers of the bacteria, approximately 15% develop peptic ulcers, which are most prevalent in the duodenum. H. pylori induce a vigorous immune response which, however, fails to clear the infection. Instead, the chronic inflammation that arises in the infected gastroduodenal mucosa may be involved in the development of H. pylori-associated peptic ulcers. We have previously shown that duodenal ulcer (DU) patients have a significantly lower epithelial cytokine, e.g. IL-8, response in the duodenum than asymptomatic (AS) carriers. In this study we have further investigated the mechanisms behind this finding, i.e. whether it can be explained by bacterial factors, down-regulation of epithelial cytokine production by regulatory T cells, or an impaired ability of the duodenal epithelium in DU patients to produce cytokines. Gastric AGS, and intestinal T84 epithelial cell lines were stimulated with H. pylori strains isolated from DU patients and AS carriers, respectively. All strains were found to induce comparable cytokine and cytokine receptor expression in epithelial cells. Regulatory T cells (CD4+ CD25(high)), isolated from human peripheral blood and cocultured with H. pylori stimulated AGS cells, were found to slightly suppress H. pylori-induced epithelial cytokine production. Furthermore, primary cultures of duodenal epithelial cells from DU patients were found to produce markedly lower amounts of cytokines than epithelial cells isolated from AS carriers. These results suggest that the lower epithelial cytokine responses in the duodenum of DU patients, which may be of importance for the pathogenesis of H. pylori-induced duodenal ulcers, most likely can be explained by host factors, i.e. mainly a decreased ability of the duodenal epithelium to produce cytokines, but possibly partly also down-regulation by regulatory T cells