H7N9 Live Attenuated Influenza Vaccine Is Highly Immunogenic, Prevents Virus Replication, and Protects Against Severe Bronchopneumonia in Ferrets.

Avian influenza viruses continue to cross the species barrier, and if such viruses become transmissible among humans, it would pose a great threat to public health. Since its emergence in China in 2013, H7N9 has caused considerable morbidity and mortality. In the absence of a universal influenza vaccine, preparedness includes development of subtype-specific vaccines. In this study, we developed and evaluated in ferrets an intranasal live attenuated influenza vaccine (LAIV) against H7N9 based on the A/Leningrad/134/17/57 (H2N2) cold-adapted master donor virus. We demonstrate that the LAIV is attenuated and safe in ferrets and induces high hemagglutination- and neuraminidase-inhibiting and virus-neutralizing titers. The antibodies against hemagglutinin were also cross-reactive with divergent H7 strains. To assess efficacy, we used an intratracheal challenge ferret model in which an acute severe viral pneumonia is induced that closely resembles viral pneumonia observed in severe human cases. A single- and two-dose strategy provided complete protection against severe pneumonia and prevented virus replication. The protective effect of the two-dose strategy appeared better than the single dose only on the microscopic level in the lungs. We observed, however, an increased lymphocytic infiltration after challenge in single-vaccinated animals and hypothesize that this a side effect of the model.

Comparative therapeutic effect of steroidal and non-steroidal anti-inflammatory drugs on pro-inflammatory cytokine production in water buffalo calves (Bubalus bubalis) naturally infected with bronchopneumonia: a randomized clinical trial.

In the current study, we compared the therapeutic effects of a non-steroidal and a steroidal anti-inflammatory drug on the production of pro-inflammatory cytokines, interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-12p40 (IL-12p40), interferon gamma (IFNγ), and tumor necrosis factor alpha (TNF-α) in the blood of water buffalo (Bubalus bubalis) calves naturally infected by bronchopneumonia. Twenty-seven buffalo calves (7 ± 2-month-old, 163 ± 12 kg) reared in smallholder farms in El-Dakahlia province in Egypt were identified to have bronchopneumonia and randomly allocated into three equal groups. Ten clinically healthy buffalo calves with negative bronchoalveolar lavage results were served as negative control. Diseased calves were treated with tulathromycin alone, a combination of tulathromycin with dexamethasone (steroidal anti-inflammatory drug) or tulathromycin with flunixin meglumine (non-steroidal anti-inflammatory drug). The results revealed significant elevations (P < 0.05) in the production of selected cytokines in all diseased calves in comparison with healthy animals. Six days post-treatment, a significant inhibition (P < 0.05) in the production of all assessed cytokines was observed in the blood of all treated calves. Interestingly, the serum concentrations of IL-1ß and IL-12p40 were returned to the normal levels in pneumonic calves treated with the combination therapy of tulathromycin and flunixin meglumine. A strong significant positive correlation (P < 0.05) was detected between clinical sum scoring and IL-12p40 and TNF-α concentrations. The obtained results indicate the selectively potent anti-inflammatory effect of flunixin meglumine on the production of pro-inflammatory cytokines in pneumonic buffalo calves and highlight the efficacy of flunixin meglumine in the treatment of bronchopneumonia in buffalo calves when used in combination with tulathromycin.

[Changes in lymphocyte subsets in infants with common lower respiratory tract infectious diseases].

OBJECTIVE: To investigate the changes and clinical significance of lymphocyte subsets in infants with bronchitis, bronchopneumonia, and bronchiolitis. METHODS: A total of 111 children with bronchitis, 418 children with bronchopneumonia, and 83 children with bronchiolitis were enrolled as disease groups, and 235 healthy children were enrolled as control group. Flow cytometry was applied to measure lymphocyte subsets. RESULTS: The bronchitis group had significantly lower numbers of T cells and CD3+CD8+ T cells than the control group (P<0.05). The bronchopneumonia group had significantly lower numbers of T cells and CD3+CD8+ T cells, a significantly higher number of T helper (Th) cells, and a significantly higher CD4/CD8 ratio than the control group, as well as a significantly higher number of Th cells than the bronchitis group. Compared with the children with mild bronchopneumonia, those with severe bronchopneumonia showed a reduction in T cells and an increase in B cells (P<0.05). The bronchiolitis group had a significantly higher number of Th cells, a significantly higher CD4/CD8 ratio, and a significantly lower number of CD3+CD8+ T cells than the control group (P<0.01). The disease groups showed a significantly higher number of B cells and a significantly lower number of natural killer cells than the control group (P<0.05). CONCLUSIONS: A low, disturbed cellular immune function and a high humoral immune function are involved in the development and progression of lower respiratory tract infectious diseases. The changes in immune function are related to the type and severity of diseases.

Amphisomal route of MHC class I cross-presentation in bacteria-infected dendritic cells.

Dendritic cells (DCs) are among the first professional APCs encountered by the obligate intracellular bacterium Chlamydia during infection. Using an established mouse bone marrow-derived DC line, we show that DCs control chlamydial infection in multiple small inclusions characterized by restricted bacterial growth, impaired cytosolic export of the virulence factor chlamydial protease-like activity factor, and interaction with guanylate-binding protein 1, a host cell factor involved in the initiation of autophagy. During maturation of infected DCs, chlamydial inclusions disintegrate, likely because they lack chlamydial protease-like activity factor-mediated protection. Released cytosolic Chlamydia are taken up by autophagosomes and colocalize with cathepsin-positive amphisomal vacuoles, to which peptide transporter TAP and upregulated MHC class I (MHC I) are recruited. Chlamydial Ags are subsequently generated through routes involving preprocessing in amphisomes via cathepsins and entry into the cytosol for further processing by the proteasome. Finally, bacterial peptides are reimported into the endosomal pathway for loading onto recycling MHC I. Thus, we unravel a novel pathway of MHC I-mediated cross-presentation that is initiated with a host cellular attack physically disrupting the parasitophorous vacuole, involves autophagy to collect cytosolic organisms into autophagosomes, and concludes with complex multistep antigenic processing in separate cellular compartments.

Dysregulation of claudin-5 in HIV-induced interstitial pneumonitis and lung vascular injury. Protective role of peroxisome proliferator-activated receptor-γ.

RATIONALE: HIV-1-induced interstitial pneumonitis (IP) is a serious complication of HIV-1 infection, characterized by inflammation and cellular infiltration in lungs, often leading to respiratory failure and death. The barrier function of the pulmonary endothelium is caused in part by tight junction (TJ) proteins, such as claudin-5. Peroxisome proliferator-activated receptor (PPAR)-γ is expressed in lung tissues and regulates inflammation. We hypothesize that HIV-1 induces vascular lung injury, and HIV-1-mediated damage of the pulmonary endothelium and IP is associated with dysregulation of PPAR-γ. OBJECTIVES: Investigate the effects of HIV-1 infection on the pulmonary microvasculature and the modulatory effects of the PPAR-γ ligands. METHODS: Using human lung tissues, we demonstrated down-regulation of claudin-5 (marker of pulmonary barrier integrity), down-regulation of PPAR-γ transcription, and expression in lung tissues of HIV-1-infected humans with IP. MEASUREMENTS AND MAIN RESULTS: Human lung microvascular endothelial cells expressed the TJ proteins claudin-5, ZO-1, and ZO-2; HIV-1 decreased TJ proteins expression and induced nuclear factor-κB promoter activity, which was reversed by PPAR-γ agonist. Using two murine HIV/AIDS models, we demonstrated decreased claudin-5 expression and increased macrophage infiltration in the lungs of HIV-1-infected animals. Activation of PPAR-γ prevented HIV-1-induced claudin-5 down-regulation and significantly reduced viremia and pulmonary macrophage infiltration. CONCLUSIONS: HIV-induced IP is associated with injury to the lung vascular endothelium, with decreased TJ and PPAR-γ expression, and increased pulmonary macrophage infiltration. PPAR-γ ligands abrogated these effects. Thus, regulation of PPAR-γ can be a therapeutic approach against HIV-1-induced vascular damage and IP in infected humans. Removal of Expression of Concern: Issues leading to the previous expression of concern for this article have been resolved after further revisions and editorial review. No further concerns exist.

Long-term effects of carbon containing engineered nanomaterials and asbestos in the lung: one year postexposure comparisons.

The hallmark geometric feature of single-walled carbon nanotubes (SWCNT) and carbon nanofibers (CNF), high length to width ratio, makes them similar to a hazardous agent, asbestos. Very limited data are available concerning long-term effects of pulmonary exposure to SWCNT or CNF. Here, we compared inflammatory, fibrogenic, and genotoxic effects of CNF, SWCNT, or asbestos in mice 1 yr after pharyngeal aspiration. In addition, we compared pulmonary responses to SWCNT by bolus dosing through pharyngeal aspiration and inhalation 5 h/day for 4 days, to evaluate the effect of dose rate. The aspiration studies showed that these particles can be visualized in the lung at 1 yr postexposure, whereas some translocate to lymphatics. All these particles induced chronic bronchopneumonia and lymphadenitis, accompanied by pulmonary fibrosis. CNF and asbestos were found to promote the greatest degree of inflammation, followed by SWCNT, whereas SWCNT were the most fibrogenic of these three particles. Furthermore, SWCNT induced cytogenetic alterations seen as micronuclei formation and nuclear protrusions in vivo. Importantly, inhalation exposure to SWCNT showed significantly greater inflammatory, fibrotic, and genotoxic effects than bolus pharyngeal aspiration. Finally, SWCNT and CNF, but not asbestos exposures, increased the incidence of K-ras oncogene mutations in the lung. No increased lung tumor incidence occurred after 1 yr postexposure to SWCNT, CNF, and asbestos. Overall, our data suggest that long-term pulmonary toxicity of SWCNT, CNF, and asbestos is defined, not only by their chemical composition, but also by the specific surface area and type of exposure.

[Treatment approaches for bronchopulmonary infection in myasthenia gravis patients].

Nineteen patients with bronchopulmonary infection and myasthenia gravis were enrolled in the study. The microbiological analysis of the specimens of phlegm and bronchial secretion revealed both grampositive and gramnegative bacteria. All the isolates were susceptible to the antibiotic used (cefoperazone/sulbactam). Intravenous immunoglobulins (IvIgs) were used to increase the treatment efficacy, to opsonize the infection foci and to decrease the hospitalization terms. The antibiotic therapy and simultaneous use of intravenous immunoglobulins provided higher clinical efficacy in 16 out of 19 patients (84.2%).

A mouse model of Acinetobacter baumannii-associated pneumonia using a clinically isolated hypervirulent strain.

Acinetobacter baumannii is an important emerging pathogen in health care-acquired infections and is responsible for severe nosocomial and community-acquired pneumonia. Currently available mouse models of A. baumannii pneumonia show poor colonization with little to no extrapulmonary dissemination. Here, we describe a mouse model of A. baumannii pneumonia using a clinical isolate (LAC-4 strain) that reliably reproduces the most relevant features of human pulmonary A. baumannii infection and pathology. Using this model, we have shown that LAC-4 infection induced rapid bacterial replication in the lungs, significant extrapulmonary dissemination, and severe bacteremia by 24 h postintranasal inoculation. Infected mice showed severe bronchopneumonia and dilatation and inflammatory cell infiltration in the perivascular space. More significantly, 100% of C57BL/6 and BALB/c mice succumbed to 10(8) CFU of LAC-4 inoculation within 48 h. When this model was used to assess the efficacy of antimicrobials, all mice treated with imipenem and tigecycline survived a lethal intranasal challenge, with minimal clinical signs and body weight loss. Moreover, intranasal immunization of mice with formalin-fixed LAC-4 protected 40% of mice from a lethal (100× 100% lethal dose) intraperitoneal challenge. Thus, this model offers a reproducible acute course of A. baumannii pneumonia without requiring additional manipulation of host immune status, which will facilitate the development of therapeutic agents and vaccines against A. baumannii pneumonia in humans.

[Clinical analysis of immune function changes in children with bronchial pneumonia].

OBJECTIVE: To investigate changes in serum complement, immunoglobulins and lymphocyte subsets in children with common and severe bronchial pneumonia, and the role of immune function testing in bronchial pneumonia. METHODS: Twenty children with common bronchial pneumonia, 20 with severe bronchial pneumonia and 20 healthy children (as controls) were enrolled in this study. Immunization rate scattering turbidimetry and six-color flow cytometry were used to detect changes in serum levels of IgA, IgG and IgM, complement C3 and C4 and CD3(+), CD4(+), CD8(+), CD16(+), CD56(+) and CD19(+) cells. RESULTS: The IgA levels of children with common and severe pneumonia were significantly lower than in the control group (P<0.05). The IgG level of children with severe pneumonia was significantly lower than in the control group (P<0.05). There were no significant differences in the levels of IgM and complement C3 and C4 between the two pneumonia groups and the control group (P>0.05). Compared with the controls, the children with severe pneumonia showed significantly lower CD4(+) and CD3(+) counts (P<0.05) and a significantly higher CD19(+) count (P<0.05), and the CD16(+) and CD56(+) counts of children with severe pneumonia were significantly lower than in the controls and in children with common pneumonia (P<0.05). There were no differences in CD8(+) count and CD4(+)/CD8(+) ratio between the two pneumonia groups and the control group (P>0.05). CONCLUSIONS: Immune dysfunction exists in children with bronchial pneumonia, especially those with severe pneumonia. Changes in immune function are correlated with the severity of pneumonia. Immune function testing in children with pneumonia has important clinical significance.

Interleukin-23-mediated inflammation in Pseudomonas aeruginosa pulmonary infection.

Pseudomonas aeruginosa is an opportunistic pathogen that is capable of causing acute and chronic pulmonary infection in the immunocompromised host. In the case of cystic fibrosis (CF), chronic P. aeruginosa infection causes increased mortality by promoting overly exuberant airway inflammation and cumulative lung damage. Identifying the key regulators of this inflammation may lead to the development of new therapies that improve P. aeruginosa-related mortality. We report here that interleukin-23 (IL-23), the cytokine most clearly tied to IL-17-mediated inflammation, also promotes IL-17-independent inflammation during P. aeruginosa pulmonary infection. During the early innate immune response, prior to IL-17 induction, IL-23 acts synergistically with IL-1ß to promote early neutrophil (polymorphonuclear leukocyte [PMN]) recruitment. However, at later time points, IL-23 also promoted IL-17 production by lung γδ T cells, which was greatly augmented in the presence of IL-1ß. These studies show that IL-23 controls two independent phases of neutrophil recruitment in response to P. aeruginosa infection: early PMN emigration that is IL-17 independent and later PMN emigration regulated by IL-17.

LncRNA NEAT1 activates MyD88/NF-κB pathway in bronchopneumonia through targeting miR-155-5p.

BACKGROUND: Bronchopneumonia is a disease of the respiratory tract. It leads to other complications and endangers life and health. Long non-coding RNA (lncRNA) participates in the occurrence and development of bronchopneumonia. Nuclear paraspeckle assembly transcript 1 (NEAT1) plays a key role in inflammatory diseases, but the function of NEAT1 in bronchopneumonia remains unclear. METHODS: RT-qPCR and Western blotting were performed to determine genes and proteins expressions. MTT was applied to test cell viability. Cell apoptosis was detected by flow cytometry. RIP was used to investigate the correlation between NEAT1 and miR-155-5p. The interaction between miR-155-5p and NEAT1 or MyD88 was evaluated by the dual-luciferase reporter gene. RESULTS: NEAT1 and MyD88 were upregulated in BEAS-2B cells by LPS, while miR-155-5p was downregulated. Knockdown of NEAT1 inhibited LPS-induced BEAS-2B cells growth inhibition by inhibiting the apoptosis. In addition, NEAT1 silencing suppressed LPS-induced inflammatory responses in BEAS-2B cells via suppression of TNF-α, IL-1ß, IL-6, and IL-18. Meanwhile, NEAT1 is directly bound to miR-155-5p to regulate MyD88/NF-κB axis, and overexpression of miR-155-5p increased cell proliferation and suppressed inflammatory factors expression levels and cell apoptosis. Furthermore, sh-NEAT1-induced inhibition of BEAS-2B cells injury was partially reversed by miR-155-5p inhibitor or MyD88 overexpression. CONCLUSION: NEAT1 silencing suppressed LPS-induced BEAS-2B cells injury and inflammation by the mediation of miR-155-5p/MyD88/NF-κB axis. Thus, our study might shed new light on exploring the new strategies for the treatment of bronchopneumonia.

Phenotypic characterization of chronic inflammation in a rare case of endobronchial carcinoma.

This report presents a phenotypical characterization of the immune cell infiltrate in a rare case of endobronchial carcinoma. A patient initially treated for an adenocarcinoma of the esophagus developed an endobronchial carcinoma surrounded by gastric metaplasia distal to a suspected gastrobronchial fistula, 11 years after esophagectomy. Our hypothesis is that the sustained exposure of the bronchial mucosa to a mixed acid and pancreatobiliary refluxate led to chronic inflammation and promoted malignant transformation. We performed an immunohistochemical study of the tumor microenvironment evaluating the density of CD3(+), CD8(+) T lymphocytes, CD20(+) B lymphocytes, CD68(+) macrophages and FoxP3(+) regulatory T cells. Quantification of immune cell density was completed using a novel software-based analysis method. Our results suggest that, within all the tissues analyzed, FoxP3(+) regulatory T cells were present at their highest density in the malignant and metaplastic tissues. The endobronchial metaplasia biopsied several years prior to the detection of the endobronchial adenocarcinoma was already densely infiltrated by B cells and macrophages, when compared to the immune cell infiltrate of the endobronchial carcinoma. Altogether, these observations support the current understanding of carcinogenesis promoted by chronic inflammation.

Structural characteristics of circulating immune complexes in calves with bronchopneumonia: Impact on the quiescent leukocytes.

Calf bronchopneumonia is accompanied by increased level of circulating immune complexes (CIC), and we analysed size, and protein and lipid constituents of these CIC with an attempt to elucidate the connection between the CIC structural properties and their capacity to modulate leukocyte function. CIC of heathy calves (CICH) and calves with naturally occurring bronchopneumonia (CICD) were isolated by PEG precipitation and analysed by electrophoresis and chromatography. The predominant CIC proteins were IgG, albumin, and transferrin. Affinity isolated serum and CIC IgG coprecipitated several proteins, but only 75 and 80 kDa proteins bound CIC IgG, exclusively. 60 and 65 kDa proteins co-precipitated with CICD IgG, unlike CICH IgG. In both CICH and CICD, oleic acid-containing phospholipids predominated. In CICD, the content of oleic and vaccenic acid was higher than in CICH, while myristic, palmitic, stearic, linoleic and arachidonic acid showed lower content. Dynamic light scattering displayed difference in particle size distribution between CICH and CICD; 1280 nm large particles were present only in CICD. The effect of CICH and CICD on mononuclear cells (MNC) and granulocytes was analysed in vitro. CICH and CICD, with slight difference in intensity, stimulate MNC apoptosis, promote cell cycle arrest of unstimulated MNC, and cell cycle progression of PHA stimulated MNC. Both CIC reduced granulocyte apoptosis after 24 h while after 48 h this effect was detected for CICD only. These results indicate that structural differences of CICH and CICD might interfere with the CIC functional capacity, which we consider important for evaluation of CIC immunoregulatory function.

Activation of pro- and anti-inflammatory responses in lung tissue injury during the acute phase of PRRSV-1 infection with the virulent strain Lena.

Porcine reproductive and respiratory syndrome virus (PRRSV) plays a key role in porcine respiratory disease complex modulating the host immune response and favouring secondary bacterial infections. Pulmonary alveolar macrophages (PAMs) are the main cells supporting PRRSV replication, with CD163 as the essential receptor for viral infection. Although interstitial pneumonia is by far the representative lung lesion, suppurative bronchopneumonia is described for PRRSV virulent strains. This research explores the role of several immune markers potentially involved in the regulation of the inflammatory response and sensitisation of lung to secondary bacterial infections by PRRSV-1 strains of different virulence. Conventional pigs were intranasally inoculated with the virulent subtype 3 Lena strain or the low virulent subtype 1 3249 strain and euthanised at 1, 3, 6 and 8 dpi. Lena-infected pigs exhibited more severe clinical signs, macroscopic lung score and viraemia associated with an increase of IL-6 and IFN-γ in sera compared to 3249-infected pigs. Extensive areas of lung consolidation corresponding with suppurative bronchopneumonia were observed in Lena-infected pigs. Lung viral load and PRRSV-N-protein+ cells were always higher in Lena-infected animals. PRRSV-N-protein+ cells were linked to a marked drop of CD163+ macrophages. The number of CD14+ and iNOS+ cells gradually increased along PRRSV-1 infection, being more evident in Lena-infected pigs. The frequency of CD200R1+ and FoxP3+ cells peaked late in both PRRSV-1 strains, with a strong correlation between CD200R1+ cells and lung injury in Lena-infected pigs. These results highlight the role of molecules involved in the earlier and higher extent of lung lesions in piglets infected with the virulent Lena strain, pointing out the activation of routes potentially involved in the restraint of the local inflammatory response.

Prolonged acquired neutropenia in children.

BACKGROUND: Acquired neutropenia is not uncommon in childhood. This study investigated the risk factors associated with developing prolonged acquired neutropenia. PROCEDURE: We reviewed 66,062 hospital admission medical records from the 5-year period January 1, 2002 to December 31, 2006 to identify neutropenic patients, with and without follow-up of their neutropenic course until December 31, 2007. After excluding patients with malignancy, collagen disease, bone marrow failure, prematurity, hereditary disease, congenital neutropenia, immunodeficiency, or status post-liver transplantation, 735 admissions with acquired neutropenia were included in our study. RESULTS: A total of 474 patients with 735 admissions had moderate or severe neutropenia during the 5-year period. Among the 252 acquired neutropenia patients who had follow-up for at least 1 month, 226 patients recovered within 3 months, while 26 patients remained neutropenic after 3 months. Of these 26 patients, 14 recovered after 1 year. An absolute neutrophil count of <500/mm(3) (odds ratio [OR]: 13.66, 95% confidence interval [CI]: 2.90-64.41), thrombocytosis (OR: 5.76, 95% CI: 1.78-18.58), and age <1 year (OR: 4.93, 95% CI: 1.03-23.54) were associated with prolonged acquired neutropenia, as shown by multivariate logistic regression. Kaplan-Meier analysis showed that neutropenia associated with cytomegalovirus (CMV) was more prolonged than neutropenia associated with influenza or Epstein-Barr virus infection. CONCLUSIONS: Prolonged acquired neutropenia was associated with younger age, thrombocytosis, and CMV infection. Neutropenic infants with CMV infection may require antiviral therapy to prevent prolonged acquired neutropenia.

Severe course of community-acquired pneumonia in an adult patient who is heterozygous for Q481P in the perforin gene: are carriers of the mutation free of risk?

Most cases of autosomal recessive hemophagocytic lymphohistiocytosis (HLH) are associated with over 50 mutations in the perforin gene. Some of these mutations have no clear functional association. Only homozygous patients display a full-blown syndrome, whereas no severe disease has been described in heterozygous carriers of these mutations despite the presence of functional and phenotypic alterations in cytotoxic cells. We study the family of a child who died from HLH at 6 months of age due to a Q481P mutation in the perforin gene. The study is particularly interesting because the patient's heterozygous father experienced severe community-acquired pneumonia that could be attributed to deficient in vitro NK cell activity despite normal perforin expression. This case report suggests that impaired NK cell activity in a heterozygote can result in poorer initial control of infections with severe clinical expression.

Comparative immunosecretome analysis of prevalent Streptococcus suis serotypes.

Streptococcus suis is a major Gram-positive swine pathogen associated with a wide variety of diseases in pigs. The efforts made to develop vaccines against this pathogen have failed because of lack of common cross-reactive antigens against different serotypes. Nowadays the interest has moved to surface and secreted proteins, as they have the highest chances to raise an effective immune response because they are in direct contact with host cells and are really exposed and accessible to antibodies. In this work, we have performed a comparative immunosecretomic approach to identify a set of immunoreactive secreted proteins common to the most prevalent serotypes of S. suis. Among the 67 proteins identified, three (SSU0020, SSU0934, and SSU0215) were those predicted extracellular proteins most widely found within the studied serotypes. These immunoreactive proteins may be interesting targets for future vaccine development as they could provide possible cross-reactivity among different serotypes of this pathogen.

Active immunization with lipopolysaccharide Pseudomonas antigen for chronic Pseudomonas bronchopneumonia in guinea pigs.

Chronic respiratory infection with Pseudomonas aeruginosa is a leading clinical problem among patients with cystic fibrosis. Because antimicrobial agents are usually ineffective in eradicating these infections, additional therapeutic or prophylactic measures should be considered. In this study, an experimental guinea pig model of chronic Pseudomonas aeruginosa bronchopneumonia was utilized to determine whether active immunization with lipopolysaccharide (LPS) P. aeruginosa antigen may favorably influence the course of this infection. Experimental pneumonia was established by tracheobronchial instillation of suspensions of microscopic agar beads, which were impregnated with viable P. aeruginosa. After 4 wk of infection, the geometric mean (reciprocal) passive hemagglutinating Pseudomonas antibody titer was 185+/-1.3, and lungs contained 16.8+/-4 x 10(3) colony-forming units Pseudomonas/ml of lung homogenate. Pseudomonas immunization, given prior to a 4-wk infection, resulted in significantly higher passive hemagglutinating titers (474+/-1.4; P < 0.05), lower numbers of viable Pseudomonas in lung tissues (2.4+/-0.6 x 10(3); P < 0.01), and reduced histopathology in lungs. In contrast, providing Pseudomonas immunization to animals 2 wk after pulmonary infection was established, offered no apparent benefit. Likewise, no protection was afforded by prophylactic immunization with a non-Pseudomonas LPS antigen (Escherichia coli J5 vaccine). Using a Raji cell assay, modified to detect circulating immune complexes in vaccinated and infected guinea pig sera, there was no evidence that active immunization increased the frequency of circulating immune complexes in infected guinea pigs. It is concluded that prophylactic immunization with Pseudomonas LPS antigen may confer protection from subsequent Pseudomonas bronchopneumonia, but that immunization during established infection is not beneficial.

Deoxynivalenol exacerbates viral bronchopneumonia induced by respiratory reovirus infection.

The trichothecene mycotoxin deoxynivalenol (DON), a frequent contaminant of cereal grains, is known to dysregulate mucosal and systemic immunity. In this study, we tested the hypothesis that DON interferes with the murine immune response to viral respiratory infection. Female Balb/c mice (5 weeks old) were orally gavaged with DON (10 mg/kg body weight [bw]) or saline vehicle and then intranasally instilled with 10(7) plaque-forming units of reovirus serotype 1, strain Lang (T1/L). At 10-day postinstillation (PI), both viral titers and reovirus L(2) gene expression were 10-fold higher in lungs of DON-treated mice than in saline controls. The lowest observed effective DON dose that impaired viral clearance was 2 mg/kg bw. Although DON amplified reovirus-induced interferon (IFN)-beta and IFN-gamma mRNA responses in lung, the toxin suppressed mRNA expression for IFN-alpha, IFN-alphabeta receptor (IFNAR), and IFN-gamma receptor (IFNGR). DON also impaired induction of two type 1 IFN-dependent antiviral genes, double-stranded RNA activated protein kinase R (PKR) and oligoadenylate synthase 2 (OAS2). Respiratory reovirus infection caused a mild bronchopneumonia in mice which was markedly exacerbated by DON as evidenced by severe inflammatory cell infiltration, marked alveolar damage, and a higher volume density of intraepithelial mucosubstances in pulmonary airways. At 3- and 7-day PI, elevations in total protein, MCP-1, TNF-alpha, total cells, macrophages, neutrophils, and lymphocytes were observed in bronchoalveolar lavage fluid (BALF) of control mice infected with reovirus. DON markedly enhanced viral-induced elevations of protein, MCP-1, TNF-alpha, and inflammatory cells in the BALF at 3-day PI. DON exposure also upregulated induction of reovirus-specific immunoglobulin A (IgA) in BALF, fecal pellets, and serum. DON's effect on BALF IgA was preceded by elevated IL-6 expression and secretion in the lung. Taken together, the results suggest that DON compromised resistance to respiratory viral infection. Reduced expression of IFNAR and type 1 IFN-mediated genes in the lung might contribute to DON impairment of pulmonary reovirus clearance, whereas exacerbation of bronchopneumonia and IgA responses corresponded to increased MCP-1, TNF-alpha, and IL-6 expression.

Canine eosinophilic bronchopneumopathy.

Eosinophilic bronchopneumopathy (EBP) is a disease characterized by eosinophilic infiltration of the lung and bronchial mucosa, as demonstrated by examination of bronchoalveolar lavage fluid cytologic preparations or histologic examination of the bronchial mucosa. Although the precise cause of EBP is unknown, a hypersensitivity to aeroallergens is suspected. The diagnosis relies on typical history and clinical signs, demonstration of bronchopulmonary eosinophilia by cytology or histopathologic examination, and exclusion of known causes of lower airway eosinophilia. Most dogs display an excellent response to oral corticosteroid therapy; however, side effects of this treatment can be limiting. New therapeutic approaches are being studied, including the use of aerosol therapy, cyclosporine, or drugs interfering with T helper 2 immune response.