Phosphorylcholine (ChoP) is found on the surface of many of the potentially invasive pathogens that colonize the mucosal surface of the respiratory tract, including members of the genera Streptococcus, Haemophilus, and Neisseria. However, for each of these species the display of ChoP is phase-variable, suggesting that in some circumstances its expression maybe disadvantageous. During the prior period, we showed that ChoP expressing variants predominate during natural human carriage and are more persistent in animal models of colonization. We propose to examine ChoP-mediated effects that promote bacterial passage through the epithelial barrier as a mechanism that facilitates persistence through evasion of normal mucosal clearance functions and contributes to disease by invasion into tissues. Bacterial expression of ChoP allows for mimicry of host phospholipids such as phosphatidylcholine and platelet activating factor (PAF). For S. pneumoniae and H. influenzae, choline is obtained exclusively from host sources. Since choline is also a nutritional requirement for host cells, choline depletion by bacteria may be an unrecognized source of cytotoxicity.
Aim 1 will examine the effect of bacterial competition for choline with host cells and its contribution to cellular damage and bacterial penetration of epithelial barriers. Mimicry of PAF also allows for attachment to epithelial cells through binding to its receptor, rPAF. PAF has been shown to induce damage to the mucosa.
Aim 2 will examine whether bacterial interaction with rPAF leads to PAF agonist activity that compromises the epithelial barrier. We have shown that ChoP is the target of both innate (C-reactive protein) and adaptive (human ChoP-specific lgG2) immune responses. The effectiveness of antibody to ChoP suggests that ChoP could serve as a common target antigen for protection against pathogens originating in the respiratory tract.
Aim 3 will determine the effects of the immune response to ChoP on colonization, where our findings demonstrate that expression of ChoP is most important to pathogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI044231-06A1
Application #
6965848
Study Section
Host Interactions with Bacterial Pathogens Study Section (HIBP)
Program Officer
Lambert, Linda C
Project Start
1999-08-01
Project End
2010-02-28
Budget Start
2005-06-01
Budget End
2006-02-28
Support Year
6
Fiscal Year
2005
Total Cost
$230,960
Indirect Cost
Name
University of Pennsylvania
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Langereis, Jeroen D; Weiser, Jeffrey N (2014) Shielding of a lipooligosaccharide IgM epitope allows evasion of neutrophil-mediated killing of an invasive strain of nontypeable Haemophilus influenzae. MBio 5:e01478-14
Langereis, Jeroen D; de Jonge, Marien I; Weiser, Jeffrey N (2014) Binding of human factor H to outer membrane protein P5 of non-typeable Haemophilus influenzae contributes to complement resistance. Mol Microbiol 94:89-106
Clark, Sarah E; Snow, Julian; Li, Jianjun et al. (2012) Phosphorylcholine allows for evasion of bactericidal antibody by Haemophilus influenzae. PLoS Pathog 8:e1002521
Clarke, Thomas B; Francella, Nicholas; Huegel, Alyssa et al. (2011) Invasive bacterial pathogens exploit TLR-mediated downregulation of tight junction components to facilitate translocation across the epithelium. Cell Host Microbe 9:404-14
Nakamura, Shigeki; Davis, Kimberly M; Weiser, Jeffrey N (2011) Synergistic stimulation of type I interferons during influenza virus coinfection promotes Streptococcus pneumoniae colonization in mice. J Clin Invest 121:3657-65
Davis, Kimberly M; Weiser, Jeffrey N (2011) Modifications to the peptidoglycan backbone help bacteria to establish infection. Infect Immun 79:562-70
Nakamura, Shigeki; Shchepetov, Mikhail; Dalia, Ankur B et al. (2011) Molecular basis of increased serum resistance among pulmonary isolates of non-typeable Haemophilus influenzae. PLoS Pathog 7:e1001247
Dalia, Ankur B; Weiser, Jeffrey N (2011) Minimization of bacterial size allows for complement evasion and is overcome by the agglutinating effect of antibody. Cell Host Microbe 10:486-96
Davis, Kimberly M; Nakamura, Shigeki; Weiser, Jeffrey N (2011) Nod2 sensing of lysozyme-digested peptidoglycan promotes macrophage recruitment and clearance of S. pneumoniae colonization in mice. J Clin Invest 121:3666-76
Weiser, Jeffrey N (2010) The pneumococcus: why a commensal misbehaves. J Mol Med (Berl) 88:97-102

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