Moxifloxacin modulates inflammation during murine pneumonia

Background

Moxifloxacin is a synthetic antibacterial agent belonging to the fluoroquinolone family. The antimicrobial activity of quinolones against Gram-positive and Gram-negative bacteria is based on their ability to inhibit topoisomerases. Quinolones are described to have immunomodulatory features in addition to their antimicrobial activities. It was the goal of this study to examine whether a short term treatment with moxifloxacin modulates the inflammation during a subsequently induced bacterial infection in an animal model.

Methods

Mice were treated with moxifloxacin or saline for two consecutive days and were subsequently intranasally infected with viable or heat-inactivated bacterial pathogens (Streptococcus pneumoniae, Pseudomonas aeruginosa) for 6 and 24 hours. Measurements of cytokines in the lungs and plasma were performed. Alveolar cells were determined in bronchoalveolar lavage fluits.

Results

The inflammation was increased after the inoculation of viable bacteria compared to inactivated bacteria. Numbers of total immune cells and neutrophils and concentrations of inflammatory mediators (e.g. KC, IL-1β, IL-17A) were significantly reduced in lungs of moxifloxacin-treated mice infected with inactivated and viable bacterial pathogens as compared to infected control mice. Plasma concentrations of inflammatory mediators were significantly reduced in moxifloxacin-treated mice. Immunohistochemistry showed a stronger infiltrate of TNF-α-expressing cells into lungs of saline-treated mice infected with viable P. aeruginosa as compared to moxifloxacin-treated mice.

Conclusions

These data show that in this pneumonia model moxifloxacin has anti-inflammatory properties beyond its antibacterial activity.     

Oral Vaccination with Lipid-Formulated BCG Induces a Long-lived,Multifunctional CD4+ T Cell Memory Immune Response

Oral delivery of BCG in a lipid formulation (Liporale™-BCG) targets delivery of viable bacilli to the mesenteric lymph nodes and confers protection against an aerosol Mycobacterium tuberculosis challenge. The magnitude, quality and duration of the effector and memory immune response induced by Liporale™-BCG vaccination is unknown. Therefore, we compared the effector and memory CD4⁺ T cell response in the spleen and lungs of mice vaccinated with Liporale™-BCG to the response induced by subcutaneous BCG vaccination. Liporale™-BCG vaccination induced a long-lived CD4⁺ T cell response, evident by the detection of effector CD4⁺ T cells in the lungs and a significant increase in the number of Ag85B tetramer-specific CD4⁺ T cells in the spleen up to 30 weeks post vaccination. Moreover, following polyclonal stimulation, Liporale™-BCG vaccination, but not s.c. BCG vaccination, induced a significant increase in both the percentage of CD4⁺ T cells in the lungs capable of producing IFNγ and the number of multifunctional CD4⁺ T cells in the lungs at 30 weeks post vaccination. These results demonstrate that orally delivered Liporale™-BCG vaccine induces a long-lived multifunctional immune response, and could therefore represent a practical and effective means of delivering novel BCG-based TB vaccines.     

M.tuberculosis Mutants Lacking Oxygenated Mycolates Show Increased Immunogenicity and Protective Efficacy as Compared to M. bovis BCG Vaccine in an Experimental Mouse Model

The existing vaccine against tuberculosis (M. bovis BCG) exerts some protection against the extrapulmonary forms of the disease, particularly in young children, but is not very effective against the pulmonary form of TB, which often results from the reactivation of a latent M. tuberculosis (M.tb)infection. Among the new approaches in TB vaccine development, live attenuated M.tb mutants are a promising new avenue. Here we report on the vaccine potential of two highly attenuated M.tb mutants, MGM1991 and M.tbhma::hyg (HMA), lacking all oxygenated mycolates in their cell wall. In C57BL/6 mice, stronger Th1 (IFN-γ, IL-2 and TNF-α) and IL-17 responses could be induced following subcutaneous vaccination with either of the two mutants, than following vaccination with M. bovis BCG. Significantly more mycobacteria specific IFN-γ producing CD4⁺ and particularly CD8⁺ T cells could be detected by intracellular cytokine staining in mice vaccinated with the M.tb mutants. Finally, vaccination with either of the two mutants conferred stronger protection against intratracheal M.tb challenge than vaccination with BCG, as indicated by reduced bacterial replication in lungs at 4 to 12 weeks after challenge. Protection against M. tb dissemination, as indicated by reduced bacterial numbers in spleen, was comparable for both mutants to protection conferred by BCG.     

Oral vaccination of mice with lipid-encapsulated Mycobacterium bovis BCG: anatomical sites of bacterial replication and immune activity

Lipid microencapsulation of Mycobacterium bovis bacille Calmette-Guérin (BCG) produces an oral delivery vaccine that can establish systemic cell-mediated immune reactivity and protection against aerosol mycobacterial challenge in mice. Here, we describe the lymphatic and mucosal sites of bacterial replication, and location of Mycobacterium-specific IFN-gamma-secreting cell populations, following oral vaccination of BALB/c mice. Eight weeks following a single oral dose of lipid-encapsulated BCG, viable BCG organisms were recovered from the mesenteric lymph nodes (MLN) of 11/12 mice investigated (93%). Live bacteria were also occasionally recovered from the cervical lymph nodes (17%) and Peyer's patches (8%), but not from homogenates of the lungs or spleen. Strong Mycobacterium-specific IFN-gamma production was recorded among isolated splenocytes, but not among populations of mononuclear cells derived from the MLN or lungs. Oral vaccination of mice with lipid-encapsulated BCG thus appears to promote a state of systemic immunological reactivity more akin to that observed following parenteral rather than conventional oral vaccination, despite the fact that replicating bacilli are restricted to lymphatic tissues of the alimentary tract. Possible patterns of lymphocyte sensitization and trafficking are discussed.     

Proteomics-Identified Bvg-Activated Autotransporters Protect against Bordetella pertussis in a Mouse Model

Pertussis is a highly infectious respiratory disease of humans caused by the bacterium Bordetella pertussis. Despite high vaccination coverage, pertussis has re-emerged globally. Causes for the re-emergence of pertussis include limited duration of protection conferred by acellular pertussis vaccines (aP) and pathogen adaptation. Pathogen adaptations involve antigenic divergence with vaccine strains, the emergence of strains which show enhanced in vitro expression of a number of virulence-associated genes and of strains that do not express pertactin, an important aP component. Clearly, the identification of more effective B. pertussis vaccine antigens is of utmost importance. To identify novel antigens, we used proteomics to identify B. pertussis proteins regulated by the master virulence regulatory system BvgAS in vitro. Five candidates proteins were selected and it was confirmed that they were also expressed in the lungs of naïve mice seven days after infection. The five proteins were expressed in recombinant form, adjuvanted with alum and used to immunize mice as stand-alone antigens. Subsequent respiratory challenge showed that immunization with the autotransporters Vag8 and SphB1 significantly reduced bacterial load in the lungs. Whilst these antigens induced strong opsonizing antibody responses, we found that none of the tested alum-adjuvanted vaccines - including a three-component aP - reduced bacterial load in the nasopharynx, suggesting that alternative immunological responses may be required for efficient bacterial clearance from the nasopharynx.     

Pneumococcal conjugate vaccine modulates macrophage-mediated innate immunity in pneumonia caused by Streptococcus pneumoniae following influenza

Pneumococcal conjugate vaccination (PCV) may prevent influenza-related pneumonia, including Streptococcus pneumoniae pneumonia. To investigate PCV efficacy against secondary pneumococcal pneumonia following influenza, PCV was administered intramuscularly 2 and 5 weeks before S. pneumoniae serotype-3 colonization of murine nasopharynges followed by intranasal challenge with a sublethal dose of influenza A virus. Bacterial and viral loads, including innate immune responses were compared across conditions. PCV vaccination improved the survival of mice with secondary pneumococcal pneumonia and significantly reduced the pulmonary bacterial burden. Increased monocyte/macrophage influx into the lungs, alleviated loss of alveolar macrophages and decreased neutrophil influx into the lungs occurred in PCV-treated mice irrespective of pneumococcal colonization. Higher monocyte chemoattractant protein 1 levels and lower levels of CXCL1, interferon-γ, interleukin-17A, and IL-10, were detected in PCV-treated mice. Additionally, PCV treatment activated the macrophage intracellular killing of S. pneumoniae. Collectively, PCV potentially modulates the host’s innate immunity and specific antibodies induction. Macrophage-related innate immunity should be further explored to elucidate the efficacy and mechanisms of PCV versus influenza-related life-threatening diseases.     

Prevention and Immunotherapy of Secondary Murine Alveolar Echinococcosis Employing Recombinant EmP29 Antigen

Alveolar echinococcosis (AE) is caused by infection with the larval stage of the tapeworm Echinococcus multilocularis. An increasing understanding of immunological events that account for the metacestode survival in human and murine AE infection prompted us to undertake explorative experiments tackling the potential of novel preventive and/or immunotherapeutic measures. In this study, the immunoprotective and immunotherapeutic ability of recombinant EmP29 antigen (rEmP29) was assessed in mice that were intraperitoneally infected with E. multilocularis metacestodes. For vaccination, three intraperitoneal injections with 20μg rEmP29 emulsified in saponin adjuvants were applied over 6 weeks. 2 weeks after the last boost, mice were infected, and at 90 days post-infection, rEmP29-vaccinated mice exhibited a median parasite weight that was reduced by 75% and 59% when compared to NaCl- or saponin–treated control mice, respectively. For immunotherapeutical application, the rEmP29 (20μg) vaccine was administered to experimentally infected mice, starting at 1 month post-infection, three times with 2 weeks intervals. Mice undergoing rEmP29 immunotherapy exhibited a median parasite load that was reduced by 53% and 49% when compared to NaCl- and saponin–treated control mice, respectively. Upon analysis of spleen cells, both, vaccination and treatment with rEmP29, resulted in low ratios of Th2/Th1 (IL-4/IFN-γ) cytokine mRNA and low levels of mRNA coding for IL-10 and IL-2. These results suggest that reduction of the immunosuppressive environment takes place in vaccinated as well as immunotreated mice, and a shift towards a Th1 type of immune response may be responsible for the observed increased restriction of parasite growth. The present study provides the first evidence that active immunotherapy may present a sustainable route for the control of AE.     

A New Recombinant BCG Vaccine Induces Specific Th17 and Th1 Effector Cells with Higher Protective Efficacy against Tuberculosis

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) that is a major public health problem. The vaccine used for TB prevention is Mycobacterium bovis bacillus Calmette-Guérin (BCG), which provides variable efficacy in protecting against pulmonary TB among adults. Consequently, several groups have pursued the development of a new vaccine with a superior protective capacity to that of BCG. Here we constructed a new recombinant BCG (rBCG) vaccine expressing a fusion protein (CMX) composed of immune dominant epitopes from Ag85C, MPT51, and HspX and evaluated its immunogenicity and protection in a murine model of infection. The stability of the vaccine in vivo was maintained for up to 20 days post-vaccination. rBCG-CMX was efficiently phagocytized by peritoneal macrophages and induced nitric oxide (NO) production. Following mouse immunization, this vaccine induced a specific immune response in cells from lungs and spleen to the fusion protein and to each of the component recombinant proteins by themselves. Vaccinated mice presented higher amounts of Th1, Th17, and polyfunctional specific T cells. rBCG-CMX vaccination reduced the extension of lung lesions caused by challenge with Mtb as well as the lung bacterial load. In addition, when this vaccine was used in a prime-boost strategy together with rCMX, the lung bacterial load was lower than the result observed by BCG vaccination. This study describes the creation of a new promising vaccine for TB that we hope will be used in further studies to address its safety before proceeding to clinical trials.     

Efficacy of Influenza Vaccination and Tamiflu? Treatment – Comparative Studies with Eurasian Swine Influenza Viruses in Pigs

Recent epidemiological developments demonstrated that gene segments of swine influenza A viruses can account for antigenic changes as well as reduced drug susceptibility of pandemic influenza A viruses. This raises questions about the efficacy of preventive measures against swine influenza A viruses. Here, the protective effect of vaccination was compared with that of prophylactic Tamiflu® treatment against two Eurasian swine influenza A viruses. 11-week-old pigs were infected by aerosol nebulisation with high doses of influenza virus A/swine/Potsdam/15/1981 (H1N1/1981, heterologous challenge to H1N1 vaccine strain) and A/swine/Bakum/1832/2000 (H1N2/2000, homologous challenge to H1N2 vaccine strain) in two independent trials. In each trial (i) 10 pigs were vaccinated twice with a trivalent vaccine (RESPIPORC® FLU3; 28 and 7 days before infection), (ii) another 10 pigs received 150 mg/day of Tamiflu® for 5 days starting 12 h before infection, and (iii) 12 virus-infected pigs were left unvaccinated and untreated and served as controls. Both viruses replicated efficiently in porcine respiratory organs causing influenza with fever, dyspnoea, and pneumonia. Tamiflu® treatment as well as vaccination prevented clinical signs and significantly reduced virus shedding. Whereas after homologous challenge with H1N2/2000 no infectious virus in lung and hardly any lung inflammation were detected, the virus titre was not and the lung pathology was only partially reduced in H1N1/1981, heterologous challenged pigs. Tamiflu® application did not affect these study parameters.In conclusion, all tested preventive measures provided protection against disease. Vaccination additionally prevented virus replication and histopathological changes in the lung of homologous challenged pigs.     

Protective and therapeutic efficacy of Mycobacterium smegmatis expressing HBHA-hIL12 fusion protein against Mycobacterium tuberculosis in mice

Tuberculosis (TB) remains a major worldwide health problem. The only vaccine against TB, Mycobacterium bovis Bacille Calmette-Guerin (BCG), has demonstrated relatively low efficacy and does not provide satisfactory protection against the disease. More efficient vaccines and improved therapies are urgently needed to decrease the worldwide spread and burden of TB, and use of a viable, metabolizing mycobacteria vaccine may be a promising strategy against the disease. Here, we constructed a recombinant Mycobacterium smegmatis (rMS) strain expressing a fusion protein of heparin-binding hemagglutinin (HBHA) and human interleukin 12 (hIL-12). Immune responses induced by the rMS in mice and protection against Mycobacterium tuberculosis (MTB) were investigated. Administration of this novel rMS enhanced Th1-type cellular responses (IFN-γ and IL-2) in mice and reduced bacterial burden in lungs as well as that achieved by BCG vaccination. Meanwhile, the bacteria load in M. tuberculosis infected mice treated with the rMS vaccine also was significantly reduced. In conclusion, the rMS strain expressing the HBHA and human IL-12 fusion protein enhanced immunogencity by improving the Th1-type response against TB, and the protective effect was equivalent to that of the conventional BCG vaccine in mice. Furthermore, it could decrease bacterial load and alleviate histopathological damage in lungs of M. tuberculosis infected mice.     

Saccharomyces cerevisiae strain UFMG 905 protects against bacterial translocation, preserves gut barrier integrity and stimulates the immune system in a murine intestinal obstruction model

Probiotic is a preparation containing microorganisms that confers beneficial effect to the host. This work assessed whether oral treatment with viable or heat-killed yeast Saccharomyces cerevisiae strain UFMG 905 prevents bacterial translocation (BT), intestinal barrier integrity, and stimulates the immunity, in a murine intestinal obstruction (IO) model. Four groups of mice were used: mice undergoing only laparotomy (CTL), undergoing intestinal obstruction (IO) and undergoing intestinal obstruction after previous treatment with viable or heat-killed yeast. BT, determined as uptake of ^99mTc-E. coli in blood, mesenteric lymph nodes, liver, spleen and lungs, was significantly higher in IO group than in CTL group. Treatments with both yeasts reduced BT in blood and all organs investigated. The treatment with both yeasts also reduced intestinal permeability as determined by blood uptake of ^99mTc-DTPA. Immunological data demonstrated that both treatments were able to significantly increase IL-10 levels, but only viable yeast had the same effect on sIgA levels. Intestinal lesions were more severe in IO group when compared to CTL and yeasts groups. Concluding, both viable and heat-killed cells of yeast prevent BT, probably by immunomodulation and by maintaining gut barrier integrity. Only the stimulation of IgA production seems to depend on the yeast viability.     

Systemic priming-boosting immunization with a trivalent plasmid DNA and inactivated murine cytomegalovirus (MCMV) vaccine provides long-term protection against viral replication following systemic or mucosal MCMV challenge

We previously demonstrated that vaccination of BALB/c mice with a pool of 13 plasmid DNAs (pDNAs) expressing murine cytomegalovirus (MCMV) genes followed by formalin-inactivated MCMV (FI-MCMV) resulted in complete protection against viral replication in the spleen and salivary glands following sublethal intraperitoneal (i.p.) challenge. Here, we found that following intranasal (i.n.) challenge, titers of virus in the lungs of the immunized mice were reduced approximately 1,000-fold relative to those for mock-immunized controls. We next sought to extend these results and to determine whether similar protection levels could be achieved by priming with a pool of three pDNAs containing three key plasmids (IE1, M84, and gB). We found that the three-pDNA priming elicited IE1- and M84-p65-specific CD8+ T lymphocytes and, following FI-MCMV boost, high levels of virion-specific immunoglobulin G (IgG) and virus-neutralizing antibodies. When mice were i.n. challenged 4 months after the last boost, titers of virus in the lungs of immunized mice were reduced 1,000- to 2,000-fold from those for controls during the peak of viral replication. Additionally, titers of virus were either at or below the detection limits for the salivary glands, liver, and spleen of the majority of the immunized mice. Following sublethal i.p. challenge, virus was undetectable in all of the above target organs of the immunized mice. Virion-specific IgA in the lungs was consistently detected by day 6 post-i.n. challenge for the immunized mice and by day 14 for controls. These results demonstrate the immunity and high levels of protection of the priming-boosting vaccination against both systemic and mucosal challenge.     

Vaccine-induced immunity against Helicobacter pylori in the absence of IL-17A

Background: Helicobacter pylori (H. pylori) is a gram negative bacterium that can cause diseases such as peptic ulcers and gastric cancer. IL‐17A, a proinflammatory cytokine that can induce the production of CXC chemokines for neutrophil recruitment, has recently been shown to be elevated in both H. pylori‐infected patients and mice. Furthermore, studies in mouse models of vaccination have reported levels significantly increased over infected, unimmunized mice and blocking of IL‐17A during the challenge phase in immunized mice reduces protective immunity. Because many aspects of immunity had redundant or compensatory mechanisms, we investigated whether mice could be protectively immunized when IL‐17A function is absent during the entire immune response using IL‐17A and IL‐17A receptor knockout (KO) mice immunized against H. pylori. Materials and Methods: Gastric biopsies were harvested from naïve, unimmunized/challenged, and immunized/challenged wild type (WT) and KO mice and analyzed for inflammation, neutrophil, and bacterial levels. Groups of IL‐17A KO mice were also treated with anti‐IFNγ or control antibodies. Results: Surprisingly, all groups of immunized KO mice reduced their bacterial loads comparably to WT mice. The gastric neutrophil counts did not vary significantly between IL‐17A KO and WT mice, whereas IL‐17RA KO mice had on average a four‐fold decrease compared to WT. Additionally, we performed an immunization study with CXCR2 KO mice and observed significant gastric neutrophils and reduction in bacterial load. Conclusion: These data suggest that there are compensatory mechanisms for protection against H. pylori and for neutrophil recruitment in the absence of an IL‐17A‐CXC chemokine pathway.     

Leishmania donovani: Acquired resistance to visceral leishmaniasis in the golden hamster

The ability to acquire resistance to visceral leishmaniasis was studied in the golden hamster. Hamsters were infected subcutaneously with Leishmania donovani and challenged 6 weeks later by an intracardial route of inoculation. Parasitization in previously infected and control hamsters after challenge was followed by spleen and liver impression smears. Hamsters receiving a previous subcutaneous infection showed significantly lower numbers of visceral parasites after challenge than control animals. Differences in parasitization between the two groups were detectable as early as 2 days after challenge. Promastigotes and both hamster or cotton rat infected spleen tissue were effective in inducing acquired resistance to infection. The golden hamster is discussed as a model for the study of immunity to kala-azar.     

Effect of Long-Term Voluntary Exercise Wheel Running on Susceptibility to Bacterial Pulmonary Infections in a Mouse Model

Regular moderate exercise has been suggested to exert anti-inflammatory effects and improve immune effector functions, resulting in reduced disease incidence and viral infection susceptibility. Whether regular exercise also affects bacterial infection susceptibility is unknown. The aim of this study was to investigate whether regular voluntary exercise wheel running prior to a pulmonary infection with bacteria (P. aeruginosa) affects lung bacteriology, sickness severity and phagocyte immune function in mice. Balb/c mice were randomly placed in a cage with or without a running wheel. After 28 days, mice were intranasally infected with P. aeruginosa. Our study showed that regular exercise resulted in a higher sickness severity score and bacterial (P. aeruginosa) loads in the lungs. The phagocytic capacity of monocytes and neutrophils from spleen and lungs was not affected. Although regular moderate exercise has many health benefits, healthy mice showed increased bacterial (P. aeruginosa) load and symptoms, after regular voluntary exercise, with perseverance of the phagocytic capacity of monocytes and neutrophils. Whether patients, suffering from bacterial infectious diseases, should be encouraged to engage in exercise and physical activities with caution requires further research.     

Control of cystic echinococcosis in the Middle Atlas,Morocco: Field evaluation of the EG95 vaccine in sheep and cesticide treatment in dogs

BackgroundCystic echinococcosis (CE) is an important cause of human morbidity and mortality worldwide, particularly in Morocco and other North African countries.Methodology/Principal findingsWe investigated the potential of three strategies to reduce Echinococcus granulosus transmission: (1) 4-monthly treatment of dogs with praziquantel, (2) vaccination of sheep with the EG95 vaccine and (3) a combination of both measures. These measures were implemented during four consecutive years in different areas of the Middle Atlas Mountains in Morocco. The outcome of the interventions was assessed through hydatid cyst (viable and non-viable) counts in liver and lungs using necropsy or in vivo ultrasound examination of the liver. A total of 402 lambs were recruited for annual vaccination with the EG95 anti-E. granulosus vaccine and 395 similar lambs were selected as non-vaccinated controls.At approximately four years of age the relative risk (estimated as odds ratio) for vaccinated sheep to have viable hydatid cysts compared with non-vaccinated controls was 3% (9.37% of the vaccinated sheep were found infected while 72.82% of the controls were infected; p = 0.002). The number of viable cysts in vaccinated animals was reduced by approximately 97% (mean counts were 0.28 and 9.18 respectively; p<0.001). An average of 595 owned dogs received 4-monthly treatment during the 44 months trial, corresponding to 91% of the owned dog population. Approximately, 5% of them were examined for E. granulosus adult worms by arecoline purge or eggs in feces (confirmed by PCR). The proportion of infected dogs significantly decreased after treatment (12% versus 35%; p<0.001). Post-treatment incidence of re-infestation corresponded to a monthly risk of 4% (95% CI: 3–6%). Treatment of owned dogs on a 4-monthly basis did not reduce the level of transmission of E. granulosus to sheep, nor did it enhance the level of control generated by vaccination of sheep with EG95, possibly because of unowned dogs and wild canids were not treated.Conclusions/SignificanceThese data suggest that vaccination of sheep with EG95 has the potential to reduce the level of CE in Morocco and in other parts of the world with similar transmission dynamics. Under the epidemiological circumstances existing in the trial area, 4-monthly treatment of owned dogs with praziquantel was insufficient to have a major impact of E. granulosus transmission to sheep.     

Intrapulmonary BCG cell wall vaccination in mice

Mice of two inbred strains, Balb/c and C3H/He, were given three dosages of mycobacterium bovis BCG (5 X 10(4), 5 X 10(2) and 5 colony forming units) by either the intravenous route or by a direct intratracheal (non-aerosol) route. The magnitude of the infectivity of these inoculae given by these routes was assessed by measurement of weight changes and mycobacterial multiplication in the spleen and lung. As expected, the Balb/c strain was more susceptible to infection than the C3H/He strain. However, for both strains, infection by the intratracheal route resulted in mycobacterial counts in the lungs which were more than seven-fold higher than mycobacterial counts after intravenous challenge. Naive Balb/c mice were immunized with BCG cell wall vaccine by the intratracheal route, by the intravenous route or by subcutaneous immunization. Four weeks later mice were challenged with live BCG by the intratracheal route. Following challenge, mycobacterial counts in the lungs of mice immunized by the intratracheal route, but not in the lungs of the mice immunized by the intravenous and subcutaneous routes, were significantly lower compared to controls. These results suggest that immunization with killed BCG by the intratracheal route imparts more effective mycobacterial intrapulmonary immunity than immunization by systemic routes.     

Early IL-17A production helps establish Mycobacterium intracellulare infection in mice

Nontuberculous mycobacteria (NTM) infection is common in patients with structural lung damage. To address how NTM infection is established and causes lung damage, we established an NTM mouse model by intranasal inoculation of clinical isolates of M. intracellulare. During the 39-week course of infection, the bacteria persistently grew in the lung and caused progressive granulomatous and fibrotic lung damage with mortality exceeding 50%. Lung neutrophils were significantly increased at 1 week postinfection, reduced at 2 weeks postinfection and increased again at 39 weeks postinfection. IL-17A was increased in the lungs at 1–2 weeks of infection and reduced at 3 weeks postinfection. Depletion of neutrophils during early (0–2 weeks) and late (32–34 weeks) infection had no effect on mortality or lung damage in chronically infected mice. However, neutralization of IL-17A during early infection significantly reduced bacterial burden, fibrotic lung damage, and mortality in chronically infected mice. Since it is known that IL-17A regulates matrix metalloproteinases (MMPs) and that MMPs contribute to the pathogenesis of pulmonary fibrosis, we determined the levels of MMPs in the lungs of M. intracellulare-infected mice. Interestingly, MMP-3 was significantly reduced by anti-IL-17A neutralizing antibody. Moreover, in vitro data showed that exogenous IL-17A exaggerated the production of MMP-3 by lung epithelial cells upon M. intracellulare infection. Collectively, our findings suggest that early IL-17A production precedes and promotes organized pulmonary M. intracellulare infection in mice, at least in part through MMP-3 production.     

Protective and Anti-Pathology Effects of Sm Fructose-1,6-Bisphosphate Aldolase-Based DNA Vaccine against Schistosoma mansoni by Changing Route of Injection

This study aimed to evaluate the efficacy of fructose-1,6-bis phosphate aldolase (SMALDO) DNA vaccination against Schistosoma mansoni infection using different routes of injection. The SMALDO has been cloned into the eukaryotic expression vector pcDNA3.1/V5-His TOPO-TA and was used in injecting Swiss albino mice intramuscularly (IM), subcutaneously (SC), or intraperitoneally (IP) (50 µg/mouse). Mice vaccinated with non-recombinant pcDNA3.1 served as controls. Each group was immunized 4 times at weeks 0, 2, 4, and 6. Two weeks after the last booster dose, all mice groups were infected with 80 S. mansoni cercariae via tail immersion. At week 8 post-infection, animals were sacrificed for assessment of parasitological and histopathological parameters. High anti-SMALDO IgG antibody titers were detected in sera of all vaccinated groups (P<0.01) compared to the control group. Both the IP and SC vaccination routes resulted in a significant reduction in worm burden (46.2% and 28.9%, respectively, P<0.01). This was accompanied by a significant reduction in hepatic and intestinal egg counts (41.7% and 40.2%, respectively, P<0.01) in the IP group only. The number of dead eggs was significantly increased in both IP and IM groups (P<0.01). IP vaccination recorded the highest significant reduction in granuloma number and diameter (54.7% and 29.2%, respectively, P<0.01) and significant increase in dead miracidia (P<0.01). In conclusion, changing the injection route of SMALDO DNA vaccination significantly influenced the efficacy of vaccination. SMALDO DNA vaccination via IP route could be a promising protective and anti-pathology vaccine candidate against S. mansoni infection.     

The receptor for advanced glycation end products promotes bacterial growth at distant body sites in Staphylococcus aureus skin infection

The receptor for advanced glycation endproducts (RAGE) has been implicated in the regulation of skin inflammation. We here sought to study the role of RAGE in host defense during skin infection caused by Staphylococcus (S.) aureus, the most common pathogen in this condition. Wild-type (Wt) and RAGE deficient (rage^−/−) mice were infected subcutaneously with S. aureus and bacterial loads and local inflammation were quantified at regular intervals up to 8 days after infection. While bacterial burdens were similar in both mouse strains at the primary site of infection, rage^−/− mice had lower bacterial counts in lungs and liver. Skin cytokine and chemokine levels did not differ between groups. In accordance with the skin model, direct intravenous infection with S. aureus was associated with lower bacterial loads in lungs and liver of rage^−/− mice. Together these data suggest that RAGE does not impact local host defense during S. aureus skin infection, but facilitates bacterial growth at distant body sites.