Display of FliC131 on the Surface of Lactococcus lactis as a Strategy to Increase its Adjuvanticity for Mucosal Immunization.

Research on innovative mucosal adjuvants is essential to develop new vaccines for safe mucosal application. In this work, we propose the development of a Lactococcus lactis that expresses a variant of flagellin on its surface (FliC131*), to increase the adjuvanticity of the living cell and cell wall-derived particles (CWDP). We optimized the expression of FliC131*, and confirmed its identity and localization by Western blot and flow cytometry. We also generated CWDP containing FliC131* (CDWP-FliC131*) and evaluated their storage stability. Lastly, we measured the human TLR5 stimulating activity in vitro and assessed the adjuvanticity in vivo using ovalbumin (OVA) as a model antigen. As a result, we generated L. lactis/pCWA-FliC131*, that expresses and displays FliC131* on its surface, obtained the corresponding CWDP-FliC131*, and showed that both activated hTLR5 in vitro in a dose-dependent manner. Furthermore, CWDP-FliC131* retained this biological activity after being lyophilized and stored for a year. Finally, intranasal immunization of mice with OVA plus live L. lactis/pCWA-FliC131* or CWDP-FliC131* induced OVA-specific IgG and IgA in serum, intestinal lavages, and bronchoalveolar lavages. Our work demonstrates the potential of this recombinant L. lactis with an enhanced adjuvant effect, prompting its further evaluation for the design of novel mucosal vaccines.

Description of New Morphological Variation of Culex (Culex) coronator Dyar and Knab, 1906 and First Report of Culex (Carrollia) bonnei Dyar, 1921 Found in the Central Region of Peru.

Mosquitoes (Diptera: Culicidae) pose a significant threat to public health worldwide, especially in tropical and subtropical regions, where they act as primary vectors in transmission of infectious agents. In Peru, 182 culicid species have been identified and several species of the genus Culex are known to transmit arboviruses. However, knowledge of mosquito diversity and distribution remains limited, with many studies focusing on specific regions only. Here, we describe a new morphological variation of Cx. (Culex) coronator Dyar and Knab, 1906, and report the presence of Culex (Carrollia) bonnei Dyar, 1921 in the central region of Peru, Huanuco. Specimens were obtained through larvae collections and identified through morphologic characterization, including dissection of male genitalia, and molecular analyses. In total, 17 mosquitoes were analyzed, and the genitalia of the male specimens allowed the identification of Cx. coronator and Cx. bonnei. Partial sequences of the CoxI gene corresponding to these two species were obtained (N = 10). Phylogenetic analysis revealed that the sequences of Cx. coronator grouped in a monophyletic clade with sequences ascribed to other species corresponding to the subgenus Carrollia, while Cx. bonnei specimens formed a monophyletic clade with homologous sequences from GenBank. This study underscores the importance of continued efforts to study the diversity and distribution of mosquitoes in Peru, including their potential role as vectors of human pathogens, to underpin effective disease control and prevention strategies, highlighting the importance of a complemented morphological and molecular analysis.

Canonical and Non-canonical Inflammasome Activation by Outer Membrane Vesicles Derived From Bordetella pertussis.

Outer Membrane Vesicles (OMVs) derived from different Gram-negative bacteria have been proposed as an attractive vaccine platform because of their own immunogenic adjuvant properties. Pertussis or whooping cough is a highly contagious vaccine-preventable respiratory disease that resurged during the last decades in many countries. In response to the epidemiological situation, new boosters have been incorporated into vaccination schedules worldwide and new vaccine candidates have started to be designed. Particularly, our group designed a new pertussis vaccine candidate based on OMVs derived from Bordetella pertussis (BpOMVs). To continue with the characterization of the immune response induced by our OMV based vaccine candidate, this work aimed to investigate the ability of OMVs to activate the inflammasome pathway in macrophages. We observed that NLRP3, caspase-1/11, and gasdermin-D (GSDMD) are involved in inflammasome activation by BpOMVs. Moreover, we demonstrated that BpOMVs as well as transfected B. pertussis lipooligosaccharide (BpLOS) induce caspase-11 (Casp11) and guanylate-binding proteins (GBPs) dependent non-canonical inflammasome activation. Our results elucidate the mechanism by which BpOMVs trigger one central pathway of the innate response activation that is expected to skew the adaptive immune response elicited by BpOMVs vaccination.

Dexamethasone primes adipocyte precursor cells for differentiation by enhancing adipogenic competency.

AIM: Dexamethasone (DXM) is a synthetic glucocorticoid whose effects in early and terminal adipogenesis have been addressed. In this study, we evaluated if DXM affects adipocyte precursor cells (APCs), priming them for further adipogenic differentiation. For this purpose, we analyzed APCs number and competency after DXM treatment. MATERIALS AND METHODS: Adult male rats were injected for 2 or 7 days with either DXM (30 µg/kg of weight, sc.) or vehicle. Stromal vascular fraction (SVF) cells from retroperitoneal adipose tissue (RPAT) were isolated to quantify APCs by flow cytometry (CD34+/CD45-/CD31-). Also, expression of competency markers (PPARγ2 and Zfp423) was assessed. Additionally, SVF cells from control rats were incubated with DXM (0.25 µM) alone or combined with a mineralocorticoid receptor (MR) antagonist (Spironolactone 10 µM) and/or a glucocorticoid receptor (GR) antagonist (RU486 1 µM) to assess APCs competency and adipocyte differentiation. KEY FINDINGS: APCs from 2 days DXM-treated rats showed increased expression of PPARγ2 and Zfp423 (competency markers), but did not affect APCs percentage by FACS analysis (CD34+/CD45-/CD31-). Additionally, we found that DXM treatment in SVF also increased APCs competency in vitro, predisposing APCs to further adipocyte differentiation. These effects on APCs were abrogated only when both, MR and GR, were blocked. SIGNIFICANCE: Overall, our results suggest that DXM primes APCs for differentiation mainly by enhancing Zfp423 and PPARγ2 expressions. Also, we showed that the inhibition of MR and GR was necessary for the complete abolishment of DXM effects.

A Pertussis Outer Membrane Vesicle-Based Vaccine Induces Lung-Resident Memory CD4 T Cells and Protection Against Bordetella pertussis, Including Pertactin Deficient Strains.

Pertussis is a respiratory infectious disease that has been resurged during the last decades. The change from the traditional multi-antigen whole-cell pertussis (wP) vaccines to acellular pertussis (aP) vaccines that consist of a few antigens formulated with alum, appears to be a key factor in the resurgence of pertussis in many countries. Though current aP vaccines have helped to reduce the morbidity and mortality associated with pertussis, they do not provide durable immunity or adequate protection against the disease caused by the current circulating strains of Bordetella pertussis, which have evolved in the face of the selection pressure induced by the vaccines. Based on the hypothesis that a new vaccine containing multiple antigens could overcome deficiencies in the current aP vaccines, we have designed and characterized a vaccine candidate based on outer membrane vesicle (OMVs). Here we show that the OMVs vaccine, but not an aP vaccine, protected mice against lung infection with a circulating pertactin (PRN)-deficient isolate. Using isogenic bacteria that in principle only differ in PRN expression, we found that deficiency in PRN appears to be largely responsible for the failure of the aP vaccine to protect against this circulating clinical isolates. Regarding the durability of induced immunity, we have already reported that the OMV vaccine is able to induce long-lasting immune responses that effectively prevent infection with B. pertussis. Consistent with this, here we found that CD4 T cells with a tissue-resident memory (TRM) cell phenotype (CD44+CD62LlowCD69+ and/or CD103+) accumulated in the lungs of mice 14 days after immunization with 2 doses of the OMVs vaccine. CD4 TRM cells, which have previously been shown to play a critical role sustained protective immunity against B. pertussis, were also detected in mice immunized with wP vaccine, but not in the animals immunized with a commercial aP vaccine. The CD4 TRM cells secreted IFN-γ and IL-17 and were significantly expanded through local proliferation following respiratory challenge of mice with B. pertussis. Our findings that the OMVs vaccine induce respiratory CD4 TRM cells may explain the ability of this vaccine to induce long-term protection and is therefore an ideal candidate for a third generation vaccine against B. pertussis.

Recombinant flagellins with deletions in domains D1, D2, and D3: Characterization as novel immunoadjuvants.

Bacterial flagellin activates the innate immune system and ultimately the adaptive immune system through a Toll-like receptor 5 (TLR5)-dependent signaling mechanism. Given that TLR5 is widely distributed in epithelia, flagellin is currently being developed as a mucosal adjuvant. Flagellin FliC from Salmonella enterica has four domains: the conserved D0 and D1 domains and the hypervariable D2 and D3 domains. The deletion of D3 and partial deletion of D2 in the recombinant FliCΔ174-400 strongly impairs flagellin's intrinsic antigenicity but does not affect the TLR5-dependent immunostimulation activity, i.e., the capacity to promote innate responses and adaptive responses to co-administered antigens. Here, we describe the development of novel recombinant flagellins with various deletions encompassing all of D2 and D3, and part of D1. Most of the recombinant molecules conserved an α-helical secondary structure that was as resistant to heat denaturation as the native protein. Whereas the recombinant flagellins' ability to trigger TLR5 varied markedly in vitro, most gave equivalent in vivo TLR5-dependent innate immune responses following intranasal administration of 2 µg of flagellin to mice. Concordantly, the recombinant flagellins were also valuable respiratory adjuvants for eliciting antibody responses to the foreign antigen ovalbumin, although their intrinsic antigenicity was decreased compared to the native flagellin and not increased compared to FliCΔ174-400. Our results show that the additional deletions of D2 and the distal part of D1 of FliCΔ174-400 does not impact on antigenicity and does not significantly modify the immunostimulatory adjuvant activity. Altogether, this study generated a novel set of recombinant flagellin that constitutes a portfolio of TLR5-dependent candidate adjuvants for vaccination.

High Risk of Metabolic and Adipose Tissue Dysfunctions in Adult Male Progeny, Due to Prenatal and Adulthood Malnutrition Induced by Fructose Rich Diet.

The aim of this work was to determine the effect of a fructose rich diet (FRD) consumed by the pregnant mother on the endocrine-metabolic and in vivo and in vitro adipose tissue (AT) functions of the male offspring in adulthood. At 60 days of age, rats born to FRD-fed mothers (F) showed impaired glucose tolerance after glucose overload and high circulating levels of leptin (LEP). Despite the diminished mass of retroperitoneal AT, this tissue was characterized by enhanced LEP gene expression, and hypertrophic adipocytes secreting in vitro larger amounts of LEP. Analyses of stromal vascular fraction composition by flow cytometry revealed a reduced number of adipocyte precursor cells. Additionally, 60 day-old control (C) and F male rats were subjected to control diet (CC and FC animals) or FRD (CF and FF rats) for three weeks. FF animals were heavier and consumed more calories. Their metabolic-endocrine parameters were aggravated; they developed severe hyperglycemia, hypertriglyceridemia, hyperleptinemia and augmented AT mass with hypertrophic adipocytes. Our study highlights that manipulation of maternal diet induced an offspring phenotype mainly imprinted with a severely unhealthy adipogenic process with undesirable endocrine-metabolic consequences, putting them at high risk for developing a diabetic state.

Relationship between the Balance of Hypertrophic/Hyperplastic Adipose Tissue Expansion and the Metabolic Profile in a High Glucocorticoids Model.

Adipose tissue (AT) expansion is the result of two processes: hyperplasia and hypertrophy; and both, directly or indirectly, depend on the adipogenic potential of adipocyte precursor cells (APCs). Glucocorticoids (GCs) have a potent stimulatory effect on terminal adipogenesis; while their effects on early stages of adipogenesis are largely unknown. In the present work, we study, in a model of high GC levels, the adipogenic potential of APCs from retroperitoneal AT (RPAT) and its relationship with RPAT mass expansion. We employed a model of hyper-adiposity (30- and 60-day-old rats) due to high endogenous GC levels induced by neonatal treatment with l-monosodium glutamate (MSG). We found that the RPAT APCs from 30-day-old MSG rats showed an increased adipogenic capacity, depending on the APCs' competency, but not in their number. Analyses of RPAT adipocyte diameter revealed an increase in cell size, regardless of the rat age, indicating the prevalence of a hypertrophic process. Moreover, functional RPAT alterations worsened in 60-day-old rats, suggesting that the hyperplastic AT expansion found in 30-day-old animals might have a protective role. We conclude that GCs chronic excess affects APCs' adipogenic capacity, modifying their competency. This change would modulate the hyperplastic/hypertrophic balance determining healthy or unhealthy RPAT expansion and, therefore, its functionality.

Long-Term Fructose Intake Increases Adipogenic Potential: Evidence of Direct Effects of Fructose on Adipocyte Precursor Cells.

We have previously addressed that fructose rich diet (FRD) intake for three weeks increases the adipogenic potential of stromal vascular fraction cells from the retroperitoneal adipose tissue (RPAT). We have now evaluated the effect of prolonged FRD intake (eight weeks) on metabolic parameters, number of adipocyte precursor cells (APCs) and in vitro adipogenic potential from control (CTR) and FRD adult male rats. Additionally, we have examined the direct fructose effects on the adipogenic capacity of normal APCs. FRD fed rats had increased plasma levels of insulin, triglyceride and leptin, and RPAT mass and adipocyte size. FACS studies showed higher APCs number and adipogenic potential in FRD RPAT pads; data is supported by high mRNA levels of competency markers: PPARγ2 and Zfp423. Complementary in vitro experiments indicate that fructose-exposed normal APCs displayed an overall increased adipogenic capacity. We conclude that the RPAT mass expansion observed in eight week-FRD fed rats depends on combined accelerated adipogenesis and adipocyte hypertrophy, partially due to a direct effect of fructose on APCs.

Strategies and new developments to control pertussis, an actual health problem.

The aim of this article is to describe the current epidemiological situation of pertussis, as well as different short-term strategies that have been implemented to alleviate this threat. The state of the art of the development of new vaccines that are expected to provide long-lasting immunity against pertussis was also included.

Glucocorticoid-dependency of increased adiposity in a model of hypothalamic obesity.

UNLABELLED: It is known that rats treated, at neonatal age, with monosodium L-glutamate (MSG) develop neuroendocrine and metabolic abnormalities, resulting in a phenotype of hypothalamic obesity, characterized by increased adiposity, corticosteronemia and leptinemia. OBJECTIVE: We explored whether adrenal manipulations could result in the reversion of this phenotype of hypothalamic obesity. EXPERIMENTAL DESIGNS: Newborn male rats, treated with MSG or vehicle (CTR), were submitted to sham operation, bilateral adrenalectomy (ADX) or bilateral adrenal enucleation (AE) on day 120 of age. Animals were examined 21 days after ADX, combined or not with corticosterone (B) substitution (ADX+B), and on days 21 and 35 after AE. Food intake, body weight and body fat mass were monitored; additionally circulating levels of insulin, leptin, ACTH and B were measured. RESULTS: Our data indicate that: a) normalization of basal B circulating levels in, 21 day-ADX and -AE, MSG rats fully reversed hyperinsulinemia, hyperleptinemia and significantly decreased body fat mass; and b) recovery of hypercorticosteronemia in, 35 day-AE, MSG rats fully restored this phenotype of hypothalamic obesity. CONCLUSION: Our study strongly supports that high glucocorticoid production is the main factor responsible for the development of enhanced adiposity in MSG rats and, importantly, that this abnormality could be reversed by an appropriate therapy.

Neonatal hypothalamic androgenization in the female rat induces changes in peripheral insulin sensitivity and adiposity function at adulthood.

UNLABELLED: It is recognized that there exists a link between hyperandrogenicity and insulin resistance. OBJECTIVE: By using the neonatally androgenized female rat we explored whether this treatment modifies peripheral insulin sensitivity and visceral fat function at adulthood. EXPERIMENTAL DESIGNS: On day 5 of age, female Sprague-Dawley pups were injected, sub cutaneous, with either 50 ml of sterile corn oil alone (CT) or containing 1.25 mg of testosterone propionate (TP) and further used for experimentation on day 100 of age. CT and TP rats were killed by decapitation in non-fasting condition and blood samples were kept frozen for measurement of different metabolites. Immediately after sacrifice, freshly dissected visceral fat pads were used for isolation of adipocytes, these cells were then incubated with medium alone or containing different concentrations of insulin in order to determine leptin secreted into the medium. Additionally, in vivo metabolic responses to intravenous high glucose load were performed in, 24 hour-fasting, CT and TP rats. RESULTS: We found that neonatal androgenization induced adult animals displaying higher visceral adiposity mass, body weight and leptinemia than CT rats. No group differences were found in basal circulating levels of several hormones and metabolic parameters. The results of the high glucose load 90-min test indicated that TP and CT rats developed similar glycemia but this accounted because of an early significantly higher peak values of circulating insulin in TP than in CT rats, regardless of similar enhancement in circulating glucocorticoid concentrations in both groups. While high glucose load significantly increased, over the baseline, circulating leptin concentrations as early as 30 min post-glucose in CT rats, in TP animals, it significantly enhanced leptinemia only by the end of the test. Finally, results of in vitro incubations of isolated visceral adipocytes indicated that cells from androgenized rats spontaneously released more leptin than control cells, although they were less responsive than CT cells to insulin-induced leptin output. CONCLUSION: Our study strongly supports the hypothesis that development of insulin resistance seems to be dependent on early hyperandrogenicity.

Characterization of the key antigenic components of pertussis vaccine based on outer membrane vesicles.

Pertussis has resurged during the last two decades in different countries. In particular in the 2010-2013 period large outbreaks were detected in US, Australia, UK and The Netherlands with significant mortality in infants. The epidemiological situation of pertussis points out the need to develop new vaccines and in this regard we previously developed a new vaccine based on outer membrane vesicles (OMVs) which have been shown to be safe and to induce protection in mice. Here we have further investigated the properties of OMVs vaccines; in particular we studied the contribution of pertussis toxin (PTx) and pertactin (Prn) in OMVs-mediated protection against pertussis. PTx-deficient OMVs and Prn-deficient OMVs were obtained from defective Bordetella pertussis mutants. The absence of PTx or Prn did compromise the protective capacity of the OMVs formulated as Tdap vaccine. Whereas the protective efficacy of the PTx-deficient OMVs in mice was comparable to Prn-deficient OMVs, the protective capacity of both of them was significantly impaired when it was compared with the wild type OMVs. Interestingly, using OMVs obtained from a B. pertussis strain which does not express any of the virulence factors but expresses the avirulent phenotype; we observed that the protective ability of such OMVs was lower than that of OMVs obtained from virulent B. pertussis phase. However, it was surprising that although the protective capacity of avirulent OMVs was lower, they were still protective in the used mice model. These results allow us to hypothesize that OMVs from avirulent phase shares protective components with all OMVs assayed. Using an immune proteomic strategy we identified some common components that could play an important role in protection against pertussis.

Acellular pertussis vaccine based on outer membrane vesicles capable of conferring both long-lasting immunity and protection against different strain genotypes.

Despite high vaccination coverage rates, pertussis continues to be a global concern, with increased incidence widely noted. The current pertussis epidemiologic situation has been mainly attributed to waning immunity and pathogen adaptation. To improve the disease control, a new generation of vaccines capable to overcome those weaknesses associated to the current vaccines need to be developed. Previously we have demonstrated that the outer membrane vesicles obtained from the recombinant Bordetella pertussis strain expressing PagL enzyme (OMVs(BpPagL)) are good vaccine candidates to protect against pertussis. In this work the OMVs(BpPagL) formulated with diphtheria and tetanus toxoids (Tdap(OMVsBpPagL)) was used to evaluate its capacity to offer protection against Argentinean clinical isolates and to induce long-term immunity. To these aims BALB/c mice were immunized with Tdap(OMVsBpPagL) and challenged with sublethal doses of the clinical isolate Bp106 selected as a representative circulating isolate. Comparisons with a current commercial Tdap vaccine used at a dose in which pertussis toxin level was equivalent to that of Tdap(OMVsBpPagL) were performed. With the normalized doses of both vaccines we observed that Tdap(OMVsBpPagL) protected against the clinical isolate infection, whereas current commercial Tdap vaccine showed little protection against such pathogen. Regarding long-term immunity we observed that the Tdap(OMVsBpPagL) protective capacity against the recommended WHO reference strain persisted at least 9 months. In agreement with these results Tdap(OMVsBpPagL) induced Th1 and Th2 immune response. In contrast, commercial Tdap induced Th2 but weak Th1 responses. All results presented here showed that Tdap(OMVsBpPagL) is an interesting formulation to be considered for the development of novel acellular multi-antigen vaccine.

Excess fructose intake-induced hypertrophic visceral adipose tissue results from unbalanced precursor cell adipogenic signals.

We studied the effect of feeding normal adult male rats with a commercial diet supplemented with fructose added to the drinking water (10% w/v; fructose-rich diet, FRD) on the adipogenic capacity of stromal-vascular fraction (SVF) cells isolated from visceral adipose tissue (VAT) pads. Animals received either the commercial diet or FRD ad libitum for 3 weeks; thereafter, we evaluated the in vitro proliferative and adipogenic capacities of their VAT SVF cells. FRD significantly increased plasma insulin, triglyceride and leptin levels, VAT mass/cell size, and the in vitro adipogenic capacity of SVF cells. Flow cytometry studies indicated that the VAT precursor cell population number did not differ between groups; however, the accelerated adipogenic process could result from an imbalance between endogenous pro- and anti-adipogenic SVF cell signals, which are clearly shifted towards the former. The increased insulin milieu and its intracellular mediator (insulin receptor substrate-1) in VAT pads, as well as the enhanced SVF cell expression of Zpf423 and peroxisome proliferator receptor-γ2 (all pro-adipogenic modulators), together with a decreased SVF cell concentration of anti-adipogenic factors (pre-adipocyte factor-1 and wingless-type MMTV-10b), strongly supports this assumption. We hypothesize that the VAT mass expansion recorded in FRD rats results from the combination of initial accelerated adipogenesis and final cell hypertrophy. It remains to be determined whether FRD administration over longer periods could perpetuate both processes, or whether cell hypertrophy itself remains responsible for a further VAT mass expansion, as observed in advanced/morbid obesity.

Toll-like receptor 4 orchestrates neutrophil recruitment into airways during the first hours of Bordetella pertussis infection.

Most of the knowledge on the impact of Bordetella pertussis lipo-oligosaccharide (LOS) on the infectious process was obtained when the bacteria was established within the host. The aim of the present work was to determine the role of TLR4 at a very early step of the infectious process. To this end we used a transcriptomic approach on B. pertussis intranasal infection model in C3H/HeN, a TLR4-competent mouse strain, and C3H/HeJ, a TLR4-deficient mouse strain. The expression of approximately 140 genes was significantly changed 2 h post-infection in the C3H/HeN animals compared to the C3H/HeJ animals, which were essentially non-responders at this early time point. Pathways specific for immunity and defense, chemokine- and cytokine-mediated functions and TLR signaling, were activated upon infection in the TLR4 competent mice either at 2 h or 24 h. Furthermore, we observed that TLR4 signaling is absolutely required to promote the rapid recruitment of neutrophils into the airways. Interestingly, the depletion of those neutrophils impacted on B. pertussis lung counts in the first three days, thereby exacerbating the lung infection. In summary, we determined that TLR4 is a central player in initial neutrophil recruitment and orchestration of the very early innate defense against B. pertussis.

In vitro functionality of isolated embryonic hypothalamic vasopressinergic and oxytocinergic neurons: modulatory effects of brain-derived neurotrophic factor and angiotensin II.

There are only a few studies on the ontogeny and differentiation process of the hypothalamic supraoptic-paraventriculo-neurohypophysial neurosecretory system. In vitro neuron survival improves if cells are of embryonic origin; however, surviving hypothalamic neurons in culture were found to express small and minimal amounts of arginine-vasopressin (AVP) and oxytocin (OT), respectively. The aim of this study was to develop a primary neuronal culture design applicable to the study of magnocellular hypothalamic system functionality. For this purpose, a primary neuronal culture was set up after mechanical dissociation of sterile hypothalamic blocks from 17-day-old Sprague-Dawley rat embryos (E17) of both sexes. Isolated hypothalamic cells were cultured with supplemented (B27)-NeuroBasal medium containing an agent inhibiting non-neuron cell proliferation. The neurosecretory process was characterized by detecting AVP and OT secreted into the medium on different days of culture. Data indicate that spontaneous AVP and OT release occurred in a culture day-dependent fashion, being maximal on day 13 for AVP, and on day 10 for OT. Interestingly, brain-derived neurotrophic factor (BDNF) and Angiotensin II (A II) were able to positively modulate neuropeptide output. Furthermore, on day 17 of culture, non-specific (high-KCl) and specific (Angiotensin II) stimuli were able to significantly (P < 0.05) enhance the secretion of both neuropeptides over respective baselines. This study suggests that our experimental design is useful for the study of AVP- and OT-ergic neuron functionality and that BDNF and A II are positive modulators of embryonic hypothalamic cell development.

Outer membrane vesicles obtained from Bordetella pertussis Tohama expressing the lipid A deacylase PagL as a novel acellular vaccine candidate.

In an effort to devise a safer and effective pertussis acelullar vaccine, outer membrane vesicles (OMVs) were engineered to decrease their endotoxicity. The pagL gene from Bordetella bronchiseptica, which encodes a lipid A 3-deacylase, was expressed in Bordetella pertussis strain Tohama I. The resulting OMVs, designated OMVs(BpPagL), contain tetra- instead of penta-acylated LOS, in addition to pertussis surface immunogens such as pertactin and pertussis toxin, as the wild type OMVs. The characterized pertussis OMVs(BpPagL) were used in murine B. pertussis intranasal (i.n.) challenge model to examine their protective capacity when delivered by i.n. routes. Immunized BALB/c mice were challenged with sublethal doses of B. pertussis. Significant differences between immunized animals and the PBS treated group were observed (p<0.001). Adequate elimination rates (p<0.005) were observed in mice immunized either with OMVs(BpPagL) and wild type OMVs. All OMV preparations tested were non toxic according to WHO criteria; however, OMVs(BpPagL) displayed almost no weight loss at 3 days post administration, indicating less toxicity when compared with wild type OMVs. Induction of IL6- and IL1-expression in lung after i.n. delivery as well as neutrophil recruitment to airways showed coincident results, with a lower induction of the proinflammatory cytokines and lower recruitment in the case of OMVs(BpPagL) compared to wild type OMVs. Given their lower endotoxic activity and retained protective capacity in the mouse model, OMVs(BpPagL) obtained from B. pertussis seem as interesting candidates to be considered for the development of novel multi-antigen vaccine.

Outer membrane vesicles as acellular vaccine against pertussis.

In this study the development and evaluation of outer membrane vesicles (OMVs) obtained from Bordetella pertussis as vaccines against pertussis disease is described. SDS-PAGE, immunoblot techniques and gel electrophoresis associated to tandem mass spectrometry were used to describe the composition of the OMVs obtained from B. pertussis Tohama CIP 8132 strain. These techniques revealed the presence of the main well-known pertussis surface immunogens in the OMVs such as pertactin, adenylate cyclase-haemolysin, pertussis toxin, as well as the lipo-oligosaccharide (LOS). A total of 43 proteins were identified by mass spectrometry. Some of them were predicted to have outer membrane or periplasmic location and the others with cytoplasmic or unknown location. The characterized pertussis OMVs were used in murine B. pertussis intranasal (i.n.) challenge model to examine their protective capacity when delivered by different routes. Killed detoxified whole-cell B. pertussis bacteria were used as reference. For intraperitoneal (i.p.) immunization, aluminum hydroxide was used as adjuvant. Since i.n. treatment with OMVs as well as killed whole-cell bacteria enhanced markers of innate immune response such as TNFalpha, IL-6 and CCL20, i.n. immunizations were performed with no adjuvant added. Immunized BALB/c mice were intranasally challenged with sublethal doses of B. pertussis. Significant differences between immunized animals and the PBS treated group were observed (p<0.001). Adequate elimination rates (p<0.005) were observed in mice immunized either with OMV or whole-cell bacteria. Comparable results were obtained with both types of immunization route. In view to their capacity to induce airways innate and protective immunity in the mouse model, OMVs obtained from B pertussis are candidates to be used to protect against pertussis.

Orexin a stimulates hypothalamic-pituitary-adrenal (HPA) axis function, but not food intake, in the absence of full hypothalamic NPY-ergic activity.

Neonatal monosodium L-glutamate (MSG) treatment destroys hypothalamic arcuate nucleus neuronal bodies, thus inducing several metabolic abnormalities. As a result, rats develop a phenotype characterized by hyperleptinemia and by impaired NPY but normal preproorexin hypothalamic mRNAs expression. Thus, our study was designed to explore whether hypothalamic effects of orexin A on food intake and glucocorticoid production develop in the absence of full hypothalamic NPY-ergic activity. For this purpose we evaluated, in control and MSG-treated rats, the consequences of intracerebroventricular (icv) orexin A administration on food intake and changes in circulating levels of ACTH and glucocorticoid. Our results indicate that orexin A icv treatment stimulated hypothalamic-pituitary-adrenal (HPA) axis activity in both MSG-damaged and normal animals, with this response even more pronounced in neurotoxin-damaged rats. Conversely, food intake was only enhanced by icv orexin A injection in normal rats. Our study further supports that acute hypothalamic effects of orexin A on food intake and glucocorticoid production are due to independent neuronal systems. While intact arcuate nucleus activity is needed for the orexinergic effect induced by icv orexin A administration, conversely, orexin A-stimulated HPA axis function takes place even in the absence of full NPY-ergic activity.