Lung pathology and immediate hypersensitivity in a mouse model after vaccination with pertussis vaccines and challenge with Bordetella pertussis

Investigation of the Cellular Immune Response to Recombinant Fragments of Filamentous Hemagglutinin and Pertactin of Bordetella pertussis in BALB/c Mice

Vaccination with whole-cell or acellular (Ac) vaccines has been very effective for the control of pertussis. The immune response to Ac vaccines has been generally associated with a shift toward the Th2 profile. In the present study, overlapping recombinant fragments of filamentous hemagglutinin (FHA) and pertactin (PRN) were produced in Escherichia coli. BALB/c mice were immunized with recombinant FHA and PRN together with the native pertussis toxin and alum or CpG as adjuvant. Immunized mice were subsequently aerosol challenged with Bordetella pertussis. Bacterial growth was assessed in bronchoalveolar lavage samples and the levels of cytokines were quantitated in supernatants of stimulated splenocytes by enzyme-linked immunosorbent assay. Our results demonstrated that both PRN and FHA antigens were able to induce IFN-γ, IL-4, and to some extent IL-17 cytokines in challenged mice. The level of IFN-γ was higher in response to CpG formulated antigens. These findings indicate immunoprotective efficacy of our recombinant FHA and PRN antigens in mice.

Symptomatic treatment of the cough in whooping cough

BACKGROUND

Around 16 million cases of whooping cough (pertussis) occur worldwide each year, mostly in low-income countries. Much of the morbidity of whooping cough in children and adults is due to the effects of the paroxysmal cough. Cough treatments proposed include corticosteroids, beta2-adrenergic agonists, pertussis-specific immunoglobulin, antihistamines and possibly leukotriene receptor antagonists (LTRAs).

OBJECTIVES

To assess the effectiveness and safety of interventions to reduce the severity of paroxysmal cough in whooping cough in children and adults.

SEARCH METHODS

We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL, 2014, Issue 1), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, the Database of Abstracts of Reviews of Effects (DARE 2014, Issue 2), accessed from The Cochrane Library, MEDLINE (1950 to 30 January 2014), EMBASE (1980 to 30 January 2014), AMED (1985 to 30 January 2014), CINAHL (1980 to 30 January 2014) and LILACS (30 January 2014). We searched Current Controlled Trials to identify trials in progress.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) and quasi-RCTs of any intervention (excluding antibiotics and vaccines) to suppress the cough in whooping cough.

DATA COLLECTION AND ANALYSIS

Two review authors (SB, MT) independently selected trials, extracted data and assessed the quality of each trial for this review in 2009. Two review authors (SB, KW) independently reviewed additional studies identified by the updated searches in 2012 and 2014. The primary outcome was frequency of paroxysms of coughing. Secondary outcomes were frequency of vomiting, frequency of whoop, frequency of cyanosis (turning blue), development of serious complications, mortality from any cause, side effects due to medication, admission to hospital and duration of hospital stay. 

MAIN RESULTS

We included 12 trials of varying sample sizes (N = 9 to 135), mainly from high-income countries, including a total of 578 participants. Ten trials recruited children (N = 448 participants). Two trials recruited adolescents and adults (N = 130 participants). We considered only three trials to be of high methodological quality (one trial each of diphenhydramine, pertussis immunoglobulin and montelukast). Included studies did not show a statistically significant benefit for any of the interventions. Only six trials, including a total of 196 participants, reported data in sufficient detail for analysis. Diphenhydramine did not change coughing episodes; the mean difference (MD) of coughing spells per 24 hours was 1.9; 95% confidence interval (CI) -4.7 to 8.5 (N = 49 participants from one trial). One trial on pertussis immunoglobulin reported a possible mean reduction of -3.1 whoops per 24 hours (95% CI -6.2 to 0.02, N = 47 participants) but no change in hospital stay (MD -0.7 days; 95% CI -3.8 to 2.4, N = 46 participants). Dexamethasone did not show a clear decrease in length of hospital stay (MD -3.5 days; 95% CI -15.3 to 8.4, N = 11 participants from one trial) and salbutamol showed no change in coughing paroxysms per day (MD -0.2; 95% CI -4.1 to 3.7, N = 42 participants from two trials). Only one trial comparing pertussis immunoglobulin versus placebo (N = 47 participants) reported data on adverse events: 4.3% in the treatment group (rash) versus 5.3% in the placebo group (loose stools, pain and swelling at injection site).

AUTHORS' CONCLUSIONS

There is insufficient evidence to draw conclusions about the effectiveness of interventions for the cough in whooping cough. More high-quality trials are needed to assess the effectiveness of potential antitussive treatments in patients with whooping cough.

Immunization with the recombinant Cholera toxin B fused to Fimbria 2 protein protects against Bordetella pertussis infection

This study examined the immunogenic properties of the fusion protein fimbria 2 of Bordetella pertussis (Fim2)—cholera toxin B subunit (CTB) in the intranasal murine model of infection. To this end B. pertussis Fim2 coding sequence was cloned downstream of the cholera toxin B subunit coding sequence. The expression and assembly of the fusion protein into pentameric structures (CTB-Fim2) were evaluated by SDS-PAGE and monosialotetrahexosylgaglioside (GM1-ganglioside) enzyme-linked immunosorbent assay (ELISA). To evaluate the protective capacity of CTB-Fim2, an intraperitoneal or intranasal mouse immunization schedule was performed with 50 μg of CTB-Fim2. Recombinant (rFim2) or purified (BpFim2) Fim2, CTB, and phosphate-buffered saline (PBS) were used as controls. The results showed that mice immunized with BpFim2 or CTB-Fim2 intraperitoneally or intranasally presented a significant reduction in bacterial lung counts compared to control groups (P < 0.01 or P < 0.001 , resp.). Moreover, intranasal immunization with CTB-Fim2 induced significant levels of Fim2-specific IgG in serum and bronchoalveolar lavage (BAL) and Fim2-specific IgA in BAL. Analysis of IgG isotypes and cytokines mRNA levels showed that CTB-Fim2 results in a mixed Th1/Th2 (T-helper) response. The data presented here provide support for CTB-Fim2 as a promising recombinant antigen against Bordetella pertussis infection.

Immunotoxicity of silver nanoparticles in an intravenous 28-day repeated-dose toxicity study in rats

Background

Nanosilver is used in a variety of medical and consumer products because of its antibacterial activity. This wide application results in an increased human exposure. Knowledge on the systemic toxicity of nanosilver is, however, relatively scarce. In a previous study, the systemic toxicity of 20 nm silver nanoparticles (Ag-NP) was studied in a 28-day repeated-dose toxicity study in rats. Ag-NP were intravenously administered with a maximum dose of 6 mg/kg body weight (bw)/day. Several immune parameters were affected: reduced thymus weight, increased spleen weight and spleen cell number, a strongly reduced NK cell activity, and reduced IFN-γ production were observed.

Methods

Prompted by these affected immune parameters, we wished to assess exposure effects on the functional immune system. Therefore, in the present study the T-cell dependent antibody response (TDAR) to keyhole limpet hemocyanin (KLH) was measured in a similar 28-day intravenous repeated-dose toxicity study. In addition, a range of immunological parameters was measured. Data obtained using the benchmark dose (BMD) approach were analyzed by fitting dose-response models to the parameters measured.

Results

A reduction in KLH-specific IgG was seen, with a lowest 5% lower confidence bound of the BMD (BMDL) of 0.40 mg/kg bw/day. This suggests that Ag-NP induce suppression of the functional immune system. Other parameters sensitive to Ag-NP exposure were in line with our previous study: a reduced thymus weight with a BMDL of 0.76 mg/kg bw/day, and an increased spleen weight, spleen cell number, and spleen cell subsets, with BMDLs between 0.36 and 1.11 mg/kg bw/day. Because the effects on the spleen are not reflected by increased KLH-specific IgG, they, however, do not suggest immune stimulation.

Conclusions

Intravenous Ag-NP administration in a 28-day repeated-dose toxicity study induces suppression of the functional immune system. This finding underscores the importance to study the TDAR to evaluate immunotoxicity and not to rely solely on measuring immune cell subsets.

Montelukast for postinfectious cough in adults: a double-blind randomised placebo-controlled trial

BACKGROUND

Postinfectious cough is common in primary care, but has no proven effective treatments. Cysteinyl leukotrienes are involved in the pathogenesis of postinfectious cough and whooping cough (pertussis). We investigated the effectiveness of montelukast, a cysteinyl leukotriene receptor antagonist, in the treatment of postinfectious cough.

METHODS

In this randomised, placebo-controlled trial, non-smoking adults aged 16-49 years with postinfectious cough of 2-8 weeks' duration were recruited from 25 general practices in England. Patients were tested for pertussis (oral fluid anti-pertussis toxin IgG) and randomly assigned (1:1) to montelukast 10 mg daily or image-matched placebo for 2 weeks. Patients chose whether to continue study drug for another 2 weeks. The randomisation sequence was computer-generated and stratified by general practice. Patients, health-care professionals, and researchers were masked to treatment allocation. Effectiveness was assessed with the Leicester Cough Questionnaire to measure changes in cough-specific quality of life; the primary outcomes were changes in total score between baseline and two follow-up stages (2 weeks and 4 weeks). The primary analysis was by intention to treat with imputation by last observation carried forward. Recruitment closed on Sept 21, 2012, and follow-up has been completed. This trial is registered with EudraCT (2010-019647-19), UKCRN Portfolio (ID 8360), and ClinicalTrials.gov (NCT01279668).

FINDINGS

From April 13, 2011, to Sept 21, 2012, we randomly assigned 276 patients to montelukast (n=137) or placebo (n=139). 70 (25%) patients had laboratory-confirmed pertussis. Improvements in cough-specific quality of life occurred in both groups after 2 weeks (montelukast: mean 2·7, 95% CI 2·2-3·3; placebo: 3·6, 2·9-4·3), but the difference between groups did not meet the minimum clinically important difference of 1·3 (mean difference -0·9, -1·7 to -0·04, p=0·04). This difference was not statistically significant in any sensitivity analyses. After 2 weeks, 192 of 259 participants from whom data were available elected to continue study drug (99 [77%] of 129 participants on montelukast; 93 [72%] of 130 on placebo). After 4 weeks, there were no significant between-group differences in cough-specific quality of life improvement (montelukast: 5·2, 4·5-5·9; placebo: 5·9, 5·1-6·7; mean difference -0·5, -1·5 to 0·6, p=0·38) or adverse event rates (21 (15%) of 137 patients on montelukast reported one or more adverse events; 31 (22%) of 139 on placebo; p=0·14). The most common adverse events reported were increased mucus production (montelukast, n=6; placebo, n=2), gastrointestinal disturbance (montelukast, n=3; placebo, n=5), and headache (montelukast, n=2; placebo, n=6). One serious adverse event was reported (placebo, n=1), which was unrelated to study drug (shortness of breath and throat tightness after severe coughing bouts).

INTERPRETATION

Montelukast is not an effective treatment for postinfectious cough. However, the burden of postinfectious cough in primary care is high, making it an ideal setting for future antitussive treatment trials.

FUNDING

National Institute for Health Research School for Primary Care Research, UK.

Statins accelerate the onset of collagen type II-induced arthritis in mice

INTRODUCTION

Statins (hydroxymethylglutaryl coenzyme A reductase inhibitors) are effective in reducing the risk of cardiovascular morbidity and mortality in patients with hyperlipidemia, hypertension, or type II diabetes. Next to their cholesterol-lowering activity, statins have immunomodulatory properties. Based on these properties, we hypothesized that statin use may eventually lead to dysregulation of immune responses, possibly resulting in autoimmunity. We have recently shown in an observational study that statin use was associated with an increased risk of developing rheumatoid arthritis. Our objective was to investigate whether a causal relationship could be established for this finding.

METHODS

The mouse collagen type II (CII)-induced arthritis (CIA) model was used, with immunization, challenge, and euthanasia at days 0, 21, and 42, respectively. Statins were given orally before (day -28 until day 21) or after (day 21 until day 42) CIA induction. Atorvastatin (0.2 mg/day) or pravastatin (0.8 mg/day) was administered. Arthritis was recorded three times a week. Serum anti-CII autoantibodies and cytokines in supernatants from Concanavalin-A-stimulated lymph node cells and CII-stimulated spleen cells were measured.

RESULTS

Statin administration accelerated arthritis onset and resulted in 100% arthritic animals, whereas only seven out of 12 nonstatin control animals developed arthritis. Atorvastatin administration after CIA induction resulted in earlier onset than atorvastatin administration before induction, or than pravastatin administration before or after induction. The arthritic score of animals given pravastatin before CIA induction was similar to that of the nonstatin controls, whereas the other groups that received statins showed higher arthritic scores. Atorvastatin administration, especially before CIA induction, increased anti-CII autoantibody production. IL-2 and IL-17 production by lymph node and spleen cells was higher in CIA animals than in PBS controls, but was not affected by statin administration. While IFNγ production was not affected by CIA induction, atorvastatin administration before CIA induction increased the production of this cytokine.

CONCLUSION

These data support previous results from our observational studies, indicating a role for statins in the induction of autoimmunity.

The role of Toll-like receptor-4 in pertussis vaccine-induced immunity

Background

The gram-negative bacterium Bordetella pertussis is an important causative agent of pertussis, an infectious disease of the respiratory tract. After introduction of whole-cell vaccines (wP) in the 1950's, pertussis incidence has decreased significantly. Because wP were found to be reactogenic, in most developed countries they have been replaced by acellular vaccines (aP). We have previously shown a role for Toll-like receptor 4 (Tlr4) in pertussis-infected mice and the pertussis toxin (Ptx)-IgG response in wP-vaccinated children, raising the issue of the relative importance of Tlr4 in wP vaccination of mice. Here we analyze the effects of wP and aP vaccination and B. pertussis challenge, in Tlr4-deficient C3H/HeJ and wild-type C3H/HeOuJ mice. aP consists of Ptx, filamentous hemagglutinin (FHA), and pertactin (Prn).

Results

We show an important role of Tlr4 in wP and (to a lesser extent) aP vaccination, induction of Th1 and Th17 cells by wP but not aP vaccination, and induction of Th17 cells by infection, confirming data by Higgins et al. (J Immunol 2006, 177:7980–9). Furthermore, in Tlr4-deficient mice, compared to wild-type controls (i) after vaccination only, Ptx-IgG (that was induced by aP but not wP vaccination), FHA-IgG, and Prn-IgG levels were similar, (ii) after infection (only), lung IL-1α and IL-1β expression were lower, (iii) after wP vaccination and challenge, Prn-IgG level and lung IL-5 expression were higher, while lung IL-1β, TNF-α, IFN-γ, IL-17, and IL-23 expression were lower, and lung pathology was absent, and (iv) after aP vaccination and challenge, Prn-IgG level and lung IL-5 expression were higher, while Ptx-IgG level was lower.

Conclusion

Tlr4 does not influence the humoral response to vaccination (without challenge), plays an important role in natural immunity, wP and aP efficacy, and induction of Th1 and Th17 responses, is critical for lung pathology and enhances pro-inflammatory cytokine production after wP vaccination and challenge, and diminishes Th2 responses after both wP and aP vaccination and challenge. wP vaccination does not induce Ptx-IgG. A role for LPS in the efficacy of wP underlines the usefulness of LPS analogs to improve bacterial subunit vaccines such as aP.

Reported pertussis infection and risk of atopy in 8- to 12-yr-old vaccinated and non-vaccinated children

Pertussis infection has been suspected to be a potential causal factor in the development of atopic disease because of the effect of pertussis immunization on specific IgE antibodies. Although several studies found a positive association between pertussis infection and atopic disorders, this relationship has not yet been studied in a population stratified by vaccination status. To assess the association between pertussis infection and atopic disorders in pertussis-unvaccinated children and in pertussis-vaccinated children. Using data from a previously conducted study on the relationship between the diphtheria-tetanus-pertussis-(inactivated) poliomyelitis vaccination in the first year of life and atopic disorders, the study population of 1872 8-12 yr old was divided into children pertussis-unvaccinated and children pertussis-vaccinated in the first year of life. Within each group, the association between pertussis infection and atopic disorders (both as reported by the parents) was assessed. In the unvaccinated group, there were no significant associations between pertussis infection and atopic disorders. In the vaccinated group, all associations between pertussis infection and atopic disorders were positive, the associations with asthma [odds ratio (OR) = 2.24, 95% confidence interval (CI(95%)): 1.36-3.70], hay fever (OR = 2.35, CI(95%): 1.46-3.77) and food allergy (OR = 2.68, CI(95%): 1.48-4.85) being significant. There was a positive association between pertussis infection and atopic disorders in the pertussis vaccinated group only. From the present study, it cannot be concluded whether this association is causal or due to reverse causation.

Lipopolysaccharide analogs improve efficacy of acellular pertussis vaccine and reduce type I hypersensitivity in mice

Pertussis is an infectious disease of the respiratory tract that is caused by the gram-negative bacterium Bordetella pertussis. Although acellular pertussis (aP) vaccines are safe, they are not fully effective and thus require improvement. In contrast to whole-cell pertussis (wP) vaccines, aP vaccines do not contain lipopolysaccharide (LPS). Monophosphoryl lipid A (MPL) and Neisseria meningitidis LpxL2 LPS have been shown to display immune-stimulating activity while exerting little endotoxin activity. Therefore, we evaluated whether these LPS analogs could increase the efficacy of the aP vaccine. Mice were vaccinated with diphtheria-tetanus-aP vaccine with aluminum, MPL, or LpxL2 LPS adjuvant before intranasal challenge with B. pertussis. Compared to vaccination with the aluminum adjuvant, vaccination with either LPS analog resulted in lower colonization and a higher pertussis toxin-specific serum immunoglobulin G level, indicating increased efficacy. Vaccination with either LPS analog resulted in reduced lung eosinophilia, reduced eosinophil numbers in the bronchoalveolar lavage fluid, and the ex vivo production of interleukin-4 (IL-4) by bronchial lymph node cells and IL-5 by spleen cells, suggesting reduced type I hypersensitivity. Vaccination with either LPS analog increased serum IL-6 levels, although these levels remained well below the level induced by wP, suggesting that supplementation with LPS analogs may induce some reactogenicity but reactogenicity considerably less than that induced by the wP vaccine. In conclusion, these results indicate that supplementation with LPS analogs forms a promising strategy that can be used to improve aP vaccines.

Effects of a diphtheria-tetanus-acellular pertussis vaccine on immune responses in murine local lymph node and lung allergy models

We have previously shown that in mice, diphtheria-tetanus-acellular pertussis (DTaP) vaccination before Bordetella pertussis infection resulted in, besides effective clearance, immediate hypersensitivity (lung eosinophilia, increased total serum immunoglobulin E [IgE], and increased ex vivo Th2 cytokine production by cells from the bronchial lymph nodes). To better appreciate the extent of these findings, we measured DTaP vaccination effects in the local lymph node assay (LLNA) and an ovalbumin (OVA) lung allergy model. In the LLNA, mice were vaccinated or adjuvant treated before being sensitized with trimellitic anhydride (TMA; inducing a Th2-directed response) and dinitrochlorobenzene (DNCB; inducing a Th1-directed response). Compared to the adjuvant-treated controls, the vaccinated mice showed a decreased response to TMA and (to a much lesser extent) an increased response to DNCB. The decreased response to TMA coincided with increased transforming growth factor beta levels. With the exception of filamentous hemagglutinin, all vaccine constituents contributed to the decreased response to TMA. In the lung allergy model, sensitization induced OVA-specific IgE, lung pathology (peribronchiolitis, perivasculitis, and hypertrophy of the bronchiolar mucus cells) and increased the number of eosinophils, lymphocytes, and neutrophils in the bronchoalveolar lavage fluid. Vaccination failed to modulate these parameters. In conclusion, although DTaP vaccination may affect the LLNA response, we found no evidence of an effect on lung allergy.