Otitis media and other illnesses caused by nontypable Haemophilus influenzae (NTHI) remain significant health problems for children in this country and elsewhere in the world. Efforts to develop vaccines for the prevention of disease are being made by a number of investigators. We have identified a family of high molecular weight outer membrane proteins nontypable Haemophilus influenzae which are major targets of host antibody both in children convalescing from nontypable Haemophilus acute otitis media and in normal adults who are naturally immune to disease. In an effort to further characterize these proteins, we have cloned, expressed, and sequenced two genes from a prototype NTHI strain which encode high molecular weight proteins identical to those recognized by the human sera. The nucleotide sequence data from these two cloned genes and additional immunologic and morphologic data suggest that the NTHI high, molecular weight proteins are structural and possibly functional analogues of the filamentous hemagglutinin protein of Bordetella Pertussis. Filamentous hemagglutinin is an important adherence factor and protective antigen of Bordetella pertussis. Our hypothesis is that the high molecular weight serve a similar functional role for NTHI. We will use several in vitro and in vivo techniques to further characterize these high molecular weight proteins and define their role in bacterial adhesion and the role of antibody directed against them in host protection. Specifically, we will perform absorption experiments to determine the contribution of antibody directed against the high molecular weight proteins to the bactericidal activity present in human sera. We will prepare antisera against purified high molecular weight proteins and assay the resulting antisera in functional assays which include bactericidal assays in vitro and animal protection experiments in the chinchilla otitis media in vivo. Active immunization experiments with purified proteins will also be performed in the animal model. We will assess the contribution of these high molecular weight proteins to the adherence of NTHI using an adenoidal organ culture model. Finally, we will further examine the relationship between the NTHI high molecular weight proteins and the filamentous hemagglutinin protein of Bordetella pertussis using several Bordetella pertussis specific adherence assays. The resulting information should be of value not only for enhancing our understanding of the biology of NTHI and but also may be of importance in efforts to develop vaccines protective against infection caused by these organisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI021707-04A2
Application #
3131980
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Project Start
1986-09-01
Project End
1995-03-31
Budget Start
1992-04-01
Budget End
1993-03-31
Support Year
4
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Saint Louis University
Department
Type
Schools of Medicine
DUNS #
City
Saint Louis
State
MO
Country
United States
Zip Code
63103
St Geme 3rd, J W; Cutter, D; Barenkamp, S J (1996) Characterization of the genetic locus encoding Haemophilus influenzae type b surface fibrils. J Bacteriol 178:6281-7
Barenkamp, S J (1996) Immunization with high-molecular-weight adhesion proteins of nontypeable Haemophilus influenzae modifies experimental otitis media in chinchillas. Infect Immun 64:1246-51
Barenkam, S J; St Geme 3rd, J W (1996) Identification of surface-exposed B-cell epitopes on high molecular-weight adhesion proteins of nontypeable Haemophilus influenzae. Infect Immun 64:3032-7
Barenkamp, S J; St Geme 3rd, J W (1996) Identification of a second family of high-molecular-weight adhesion proteins expressed by non-typable Haemophilus influenzae. Mol Microbiol 19:1215-23
Barenkamp, S J; St Geme 3rd, J W (1994) Genes encoding high-molecular-weight adhesion proteins of nontypeable Haemophilus influenzae are part of gene clusters. Infect Immun 62:3320-8
Bakaletz, L O; Barenkamp, S J (1994) Localization of high-molecular-weight adhesion proteins of nontypeable Haemophilus influenzae by immunoelectron microscopy. Infect Immun 62:4460-8
St Geme 3rd, J W; Falkow, S; Barenkamp, S J (1993) High-molecular-weight proteins of nontypable Haemophilus influenzae mediate attachment to human epithelial cells. Proc Natl Acad Sci U S A 90:2875-9
Barenkamp, S J (1992) Outer membrane proteins and lipopolysaccharides of nontypeable Haemophilus influenzae. J Infect Dis 165 Suppl 1:S181-4
Barenkamp, S J; Leininger, E (1992) Cloning, expression, and DNA sequence analysis of genes encoding nontypeable Haemophilus influenzae high-molecular-weight surface-exposed proteins related to filamentous hemagglutinin of Bordetella pertussis. Infect Immun 60:1302-13
Barenkamp, S J; Bodor, F F (1990) Development of serum bactericidal activity following nontypable Haemophilus influenzae acute otitis media. Pediatr Infect Dis J 9:333-9

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