Moraxella catarrhalis is acknowledged as an important cause of otitis media in infants and very young children and can also cause exacerbations of chronic obstructive pulmonary disease in adults. Little is known about the gene products that allow M. catarrhalis to colonize the nasopharyngeal mucosa and then cause disease in the respiratory tract. The ability of this organism to colonize the mucosal surface of the nasopharynx is crucial to its ability to cause disease in other anatomic regions because this colonization event provides a foothold for M. catarrhalis in its human host. It has been shown that M. catarrhalis forms a biofilm in vivo. We have now identified two different surface proteins (UspA1 and Hag) that form projections on the surface of this bacterium and which are involved in biofilm development. In the first Specific Aim, we will perform structure-function analysis to identify the specific regions of the UspA1 and Hag proteins that are essential for biofilm development. In the second Specific Aim, we will identify those M. catarrhalis surface proteins that are induced or up-regulated when this organism attaches to human cells or when this organism grows in vivo. In the third Specific Aim, we will use mutant analysis together with a chinchilla model of nasopharyngeal colonization by M. catarrhalis to determine which of these surface-exposed proteins of this organism are essential for nasopharyngeal colonization. Finally, in the fourth Specific Aim, we will use this chinchilla model to determine which of these surface proteins can induce the synthesis of antibodies which inhibit or prevent nasopharyngeal colonization by M. catarrhalis. Information gained from this study will directly benefit efforts to develop an effective vaccine to prevent respiratory tract disease caused by M. catarrhalis

Public Health Relevance

Moraxella catarrhalis is a bacterial pathogen that is an important cause of ear infections in babies and serious respiratory tract disease in adults with certain preexisting problems (i.e., chronic obstructive pulmonary disease). Information obtained from this research will identify components of this bacterium that have the potential to be developed into a vaccine to protect against M. catarrhalis disease.

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National Institute of Allergy and Infectious Diseases (NIAID)
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Special Emphasis Panel (ZRG1-IDM-H (02))
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Taylor, Christopher E,
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University of Texas Sw Medical Center Dallas
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Wang, Wei; Joslin, Stephanie N; Pybus, Christine et al. (2014) Identification of an outer membrane lipoprotein involved in nasopharyngeal colonization by Moraxella catarrhalis in an animal model. Infect Immun 82:2287-99
Evans, Amanda S; Pybus, Christine; Hansen, Eric J (2013) Development of a LacZ-based transcriptional reporter system for use with Moraxella catarrhalis. Plasmid 69:180-5
Hoopman, Todd C; Liu, Wei; Joslin, Stephanie N et al. (2012) Use of the chinchilla model for nasopharyngeal colonization to study gene expression by Moraxella catarrhalis. Infect Immun 80:982-95
Hoopman, Todd C; Liu, Wei; Joslin, Stephanie N et al. (2011) Identification of gene products involved in the oxidative stress response of Moraxella catarrhalis. Infect Immun 79:745-55
Wang, Wei; Kinkel, Traci; Martens-Habbena, Willm et al. (2011) The Moraxella catarrhalis nitric oxide reductase is essential for nitric oxide detoxification. J Bacteriol 193:2804-13
Attia, Ahmed S; Sedillo, Jennifer L; Hoopman, Todd C et al. (2009) Identification of a bacteriocin and its cognate immunity factor expressed by Moraxella catarrhalis. BMC Microbiol 9:207
Wang, Wei; Richardson, Anthony R; Martens-Habbena, Willm et al. (2008) Identification of a repressor of a truncated denitrification pathway in Moraxella catarrhalis. J Bacteriol 190:7762-72
Brooks, Michael J; Sedillo, Jennifer L; Wagner, Nikki et al. (2008) Modular arrangement of allelic variants explains the divergence in Moraxella catarrhalis UspA protein function. Infect Immun 76:5330-40
Brooks, Michael J; Sedillo, Jennifer L; Wagner, Nikki et al. (2008) Moraxella catarrhalis binding to host cellular receptors is mediated by sequence-specific determinants not conserved among all UspA1 protein variants. Infect Immun 76:5322-9
Hoopman, Todd C; Wang, Wei; Brautigam, Chad A et al. (2008) Moraxella catarrhalis synthesizes an autotransporter that is an acid phosphatase. J Bacteriol 190:1459-72

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