Protein D, the glycerophosphodiester phosphodiesterase from Haemophilus influenzae with affinity for human immunoglobulin D, influences virulence in a rat otitis model
1994 (English)In: Infection and Immunity, ISSN 0019-9567, Vol. 62, no 11, 4848-4854 p.Article in journal (Refereed) Published
A mutant lacking the ability to express the surface-exposed lipoprotein protein D was constructed by linker insertion and deletion mutagenesis of a cloned DNA insert containing the protein D structural gene from a nontypeable Haemophilus influenzae strain (NTHi). An isogenic NTHi mutant was isolated after transformation of genetically competent bacteria. The transformant was unreactive to a protein D-specific monoclonal antibody in a colony immunoassay. In addition, the mutant lacked the ability to synthesize detectable levels of protein D by protein staining, immunoblot methods, glycerophosphodiester phosphodiesterase activity, and binding studies of radiolabelled immunoglobulin D. The isogenic protein D-deficient mutant was compared with its parental strain for its ability to induce experimental otitis media in rats challenged with bacteria. An approximately 100-times-higher concentration of the mutant compared with that of the wild-type strain was required in order to cause otitis among all rats challenged with that given dose. The protein D mutant exhibited a generation time that was equal to that of the wild-type strain in complex broth medium. No difference in lipopolysaccharide expression was found between the mutant and the parental strain. These results suggest that protein D may influence the pathogenesis of NTHi in the upper respiratory tract.
Place, publisher, year, edition, pages
1994. Vol. 62, no 11, 4848-4854 p.
Animals, Bacterial Proteins, Base Sequence, Carrier Proteins/*physiology, DNA Primers, Genes; Bacterial, Haemophilus Infections/*microbiology, Haemophilus influenzae/enzymology/genetics/*pathogenicity, Immunoglobulin D/*immunology, Lipoproteins/*physiology, Male, Molecular Sequence Data, Mutagenesis; Insertional, Otitis Media/*microbiology, Phosphoric Diester Hydrolases/*physiology, Rats, Rats; Sprague-Dawley, Research Support; Non-U.S. Gov't, Sequence Deletion
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-83432PubMedID: 7927765OAI: oai:DiVA.org:uu-83432DiVA: diva2:111340