Modeling Adenovirus Type 1-Induced Otitis Media in the Chinchilla: Effect on Ciliary Activity and Fluid Transport Function of Eustachian Tube Mucosal Epithelium

Daniels, Robert L.; Lim, David J.

doi:10.1093/infdis/168.4.865

Cited by 56 publications

(53 citation statements)

References 23 publications

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“…challenge with any of the three NTHI isolates selected, although there were similar group-specific differences noted in the ability to totally eradicate NTHI from the NP among cohorts receiving either anti-LB1 or anti-LPD-LB1(f) 2,1,3 . While a group 1-specific clearance response in the NP could have perhaps been anticipated in animals that received anti-LB1, the immunogen LPD-LB1(f) 2,1,3 was designed to overcome this limitation.…”

Section: Discussionmentioning

confidence: 83%

See 1 more Smart Citation

Passive Transfer of Antiserum Specific for Immunogens Derived from a Nontypeable Haemophilus influenzae Adhesin and Lipoprotein D Prevents Otitis Media after Heterologous Challenge

et al. 2000

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We recently determined that passive transfer of serum directed against a synthetic peptide called LB1 or a recombinant fusion protein immunogen [LPD-LB1(f) 2,1,3 ] could prevent otitis media after challenge with a homologous nontypeable Haemophilus influenzae (NTHI) isolate. NTHI residing in the nasopharynx was rapidly cleared from this site, thus preventing it from ascending the eustachian tube and inducing otitis media in chinchillas compromised by an ongoing viral upper respiratory tract infection. While LB1 is based solely on one NTHI adhesin, the latter immunogen, LPD-LB1(f) 2,1,3 , was designed to incorporate two NTHI antigens shown to play a role in the pathogenesis of otitis media; lipoprotein D (LPD) and the P5-homologous fimbrin adhesin. The design of LPD-LB1(f) 2,1,3 also accommodated for the recently demonstrated existence of three major groupings, based on amino acid sequence diversity, in the third surface-exposed region of P5-fimbrin. LPD-LB1(f) 2,1,3 was thus designed to potentially confer broader protection against challenge by diverse strains of NTHI. Chinchillas were passively immunized here with serum specific for either LB1 or for LPD-LB1(f) 2,1,3 prior to challenge with a member of all three groups of NTHI relative to diversity in region 3. The transferred serum pools were also analyzed for titer, specificity, and several functional activities. We found that both serum pools had equivalent ability to mediate C-dependent killing and to inhibit adherence of NTHI strains to human oropharyngeal cells. When passively transferred, both serum pools significantly inhibited the signs and incidence of otitis media (P < 0.01) induced by any of the three challenge isolates. Despite providing protection against disease, the ability of these antisera to induce total eradication of NTHI from the nasopharynx was not equivalent among NTHI groups. These data thus suggested that while early, complete eradication of NTHI from the nasopharynx was highly protective, reduction of the bacterial load to below a critical threshold level appeared to be similarly effective.Our laboratory has focused on a specific 19-mer portion of the outer membrane protein (OMP) P5-homologous fimbrin adhesin (P5-fimbrin) of nontypeable Haemophilus influenzae (NTHI) as a potential protective antigen. This region of the adhesin protein resides in the third of four predicted surface exposed areas of the mature 36.4-kDa protein and served as the basis for the design of a synthetic chimeric 40-mer peptide immunogen known as LB1 (5). LB1 proved to be highly efficacious as an immunogen in chinchilla models, inducing antibody that (i) significantly augmented the clearance of NTHI from the colonized nasopharynx (NP), (ii) significantly augmented the clearance of NTHI from a directly challenged middle ear, and (iii) (when passively transferred) also protected against ascension of the eustachian tube and development of otitis media (OM) by a homologous challenge isolate in adenovirus-compromised chinchillas (4). Despite the demonstrated efficac...

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Section: Discussionmentioning

confidence: 83%

“…Both strains 86-028L and 266NP share identical LB1(f) amino acid sequences with the strains they are replacing (4). Adenovirus serotype 1 was also recovered from a pediatric patient at Columbus Children's Hospital and has been used in chinchilla models (2,3,6,22).…”

Section: Animalsmentioning

confidence: 99%

Passive Transfer of Antiserum Specific for Immunogens Derived from a Nontypeable Haemophilus influenzae Adhesin and Lipoprotein D Prevents Otitis Media after Heterologous Challenge

et al. 2000

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“…Nasopharyngeal lavage was performed on days 1, 4, 7, 10, 14, and 18 postchallenge to determine the relative abilities of these isolates to colonize the nasopharynx (NP) of this host. Nasopharyngeal lavage was performed by passive inhalation of 500 l sterile saline followed by recovery of the lavage fluid as described previously (4,27). To evaluate the adherent population of bacteria, the chinchillas were sacrificed on day 18 postinoculation, and the nasopharyngeal tissues were harvested, weighed, and homogenized.…”

Section: Methodsmentioning

confidence: 99%

Contribution of Moraxella catarrhalis Type IV Pili to Nasopharyngeal Colonization and Biofilm Formation

et al. 2007

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Moraxella catarrhalis is a gram-negative mucosal pathogen of the human respiratory tract. Although little information is available regarding the initial steps of M. catarrhalis pathogenesis, this organism must be able to colonize the human mucosal surface in order to initiate an infection. Type IV pili (TFP), filamentous surface appendages primarily comprised of a single protein subunit termed pilin, play a crucial role in the initiation of disease by a wide range of bacteria. We previously identified the genes that encode the major proteins involved in the biosynthesis of M. catarrhalis TFP and determined that the TFP expressed by this organism are highly conserved and essential for natural transformation. We extended this initial study by investigating the contribution of TFP to the early stages of M. catarrhalis colonization. TFP-deficient M. catarrhalis bacteria exhibit diminished adherence to eukaryotic cells in vitro. Additionally, our studies demonstrate that M. catarrhalis cells form a mature biofilm in continuous-flow chambers and that biofilm formation is enhanced by TFP expression. The potential role of TFP in colonization by M. catarrhalis was further investigated using in vivo studies comparing the abilities of wild-type M. catarrhalis and an isogenic TFP mutant to colonize the nasopharynx of the chinchilla. These results suggest that the expression of TFP contributes to mucosal airway colonization. Furthermore, these data indicate that the chinchilla model of nasopharyngeal colonization provides an effective animal system for studying the early steps of M. catarrhalis pathogenesis.Moraxella catarrhalis, a gram-negative mucosal pathogen of the human respiratory tract, can also reside as a nasopharyngeal commensal. M. catarrhalis is capable of causing multiple diseases of the upper respiratory tract, including sinusitis, laryngitis, and acute and chronic otitis media, predominantly in pediatric populations, as well as recurrent exacerbations of chronic obstructive pulmonary disease in adults with underlying lung disease (31, 41). As with many other pathogenic bacteria, adherence to host tissues and subsequent colonization of the respiratory tract mucosa are believed to be essential prior to the development of M. catarrhalis infections.M. catarrhalis expresses a number of cell surface components that have been postulated to be involved in bacterial virulence (reviewed in references 29 and 41). However, in vivo studies of M. catarrhalis pathogenesis have been limited by the lack of an effective animal model to investigate bacterial colonization of the upper respiratory tract epithelium. Even with the most prevalently used model system, the mouse pulmonary clearance model, M. catarrhalis is markedly cleared from the site within 6 h and the organism is almost completely eradicated by 24 h (40). Although little information is available regarding the actual steps involved in the pathogenesis of M. catarrhalis infections in vivo, it is clear that this organism must attach to the mucosal surface in order to ...

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“…Healthy adult chinchillas (Chinchilla lanigera) with no evidence of middle ear infection by either otoscopy or tympanometry were used to screen the library for promoter activity in vivo. This chinchilla model of NTHI-induced OM has been well characterized (3,4,42) and has been used to determine the protective efficacy of several NTHI outer membrane proteins, combinations of outer membrane proteins, chimeric synthetic peptide vaccine components, and adjuvant formulations as vaccinogens against OM (5,6,26). Two pools of the NTHI/pRSM2169 library (1,000 clones each) were grown overnight on chocolate agar containing kanamycin.…”

Section: Methodsmentioning

confidence: 99%

Nontypeable Haemophilus influenzae Gene Expression Induced In Vivo in a Chinchilla Model of Otitis Media

2003

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The gram-negative bacterium nontypeable Haemophilus influenzae (NTHI) is the predominant pathogen in chronic otitis media with effusion and, with Streptococcus pneumoniae and Moraxella catarrhalis, is a causative agent of acute otitis media. To identify potential virulence determinants, bacterial gene expression was monitored by differential fluorescence induction during early disease progression in one specific anatomical niche of a chinchilla model of NTHI-induced otitis media. Genomic DNA fragments from NTHI strain 86-028NP were cloned upstream of the promoterless gfpmut3 gene. NTHI strain 86-028NP served as the host for the promoter trap library. Pools of 2,000 transformants were inoculated into the left and right middle ear cavities of chinchillas. Middle ear effusions were recovered by epitympanic tap at 24 and 48 h, and clones containing promoter elements that were induced in vivo and producing green fluorescent protein were isolated by two-color fluorescence-activated cell sorting. Insert DNA was sequenced and compared to the complete genome sequence of H. influenzae strain Rd. In a screen of 16,000 clones, we have isolated 44 clones that contain unique gene fragments encoding biosynthetic enzymes, metabolic and regulatory proteins, and hypothetical proteins of unknown function. An additional eight clones contain gene fragments unique to our NTHI isolate. Using quantitative reverse transcription-PCR, we have confirmed that 26 clones demonstrated increased gene expression in vivo relative to expression in vitro. These data provide insight into the response of NTHI bacteria as they sense and respond to the middle ear microenvironment during early events of otitis media.Otitis media (OM) is a highly prevalent pediatric disease worldwide and is the primary cause for emergency room visits by children (24). While it is rarely associated with mortality any longer, the morbidity associated with OM is significant. Hearing loss is a common problem associated with this disease, often affecting a child's behavior, education, and development of language skills (7,23,43). The socioeconomic impact of OM is also great, with direct and indirect costs of diagnosing and managing OM exceeding $5 billion annually in the United States alone (25).Whereas antibiotic therapy is common and the surgical placement of tympanostomy tubes has been successful in terms of draining effusions, clearing infection, and relieving pain associated with the accumulation of fluids in the middle ear, the emergence of multiple antibiotic-resistant bacteria and the invasiveness of tube placement have revealed the need for more effective and accepted approaches to the management and, preferably, the prevention of OM. Progress in vaccine development is most advanced for Streptococcus pneumoniae, the primary causative agent of acute OM (AOM), as evidenced by the recent approval and release of a heptavalent pneumococcal conjugate vaccine (19). While this vaccine has been highly efficacious for invasive pneumococcal disease and pneumococcal AOM, reports...

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Modeling Adenovirus Type 1-Induced Otitis Media in the Chinchilla: Effect on Ciliary Activity and Fluid Transport Function of Eustachian Tube Mucosal Epithelium

Cited by 56 publications

References 23 publications

Passive Transfer of Antiserum Specific for Immunogens Derived from a Nontypeable Haemophilus influenzae Adhesin and Lipoprotein D Prevents Otitis Media after Heterologous Challenge

Passive Transfer of Antiserum Specific for Immunogens Derived from a Nontypeable Haemophilus influenzae Adhesin and Lipoprotein D Prevents Otitis Media after Heterologous Challenge

Contribution of Moraxella catarrhalis Type IV Pili to Nasopharyngeal Colonization and Biofilm Formation

Nontypeable Haemophilus influenzae Gene Expression Induced In Vivo in a Chinchilla Model of Otitis Media

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