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PMID:12933840

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Citation

Holm, MM, Vanlerberg, SL, Sledjeski, DD and Lafontaine, ER (2003) The Hag protein of Moraxella catarrhalis strain O35E is associated with adherence to human lung and middle ear cells. Infect. Immun. 71:4977-84

Abstract

Previous studies have demonstrated that the Moraxella catarrhalis surface antigen UspA1 is an adhesin for Chang human conjunctival cells. The present report demonstrates that lack of UspA1 expression does not affect the adherence of strain O35E to A549 human lung cells or primary cultures of human middle ear epithelial (HMEE) cells. These results imply that another molecule mediates the adherence of M. catarrhalis to these two cell lines. To identify this adhesin, strain O35E was mutagenized with a transposon and 1,000 mutants were screened in a microcolony formation assay using A549 cells. Nine independent isolates exhibited an 8- to 19-fold reduction in adherence and contained a transposon in the same locus. Nucleotide sequence data and PCR analysis indicated that the transposons were inserted in different locations in the gene encoding the surface protein Hag. Quantitative assays using one representative transposon mutant, O35E.TN2, showed considerably decreased binding to A549 as well as HMEE cells. However, this mutant adhered at wild-type levels to Chang conjunctival cells. These findings suggest that the M. catarrhalis Hag protein is an adhesin for cell lines derived from human lung and middle ear tissues.

Links

PubMed PMC187358

Keywords

Adhesins, Bacterial/genetics; Adhesins, Bacterial/physiology; Bacterial Adhesion/genetics; Bacterial Adhesion/physiology; Bacterial Proteins/genetics; Bacterial Proteins/physiology; Base Sequence; Cell Line; DNA, Bacterial/genetics; Ear, Middle/cytology; Ear, Middle/microbiology; Genes, Bacterial; Hemagglutinins/genetics; Hemagglutinins/physiology; Humans; Lung/cytology; Lung/microbiology; Moraxella (Branhamella) catarrhalis/genetics; Moraxella (Branhamella) catarrhalis/immunology; Moraxella (Branhamella) catarrhalis/pathogenicity; Moraxella (Branhamella) catarrhalis/physiology; Mutagenesis, Insertional; Mutation; Phenotype

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

MORCA:Q8KQM9

GO:0007157: heterophilic cell-cell adhesion

ECO:0000315:

P

Table 2 As determined by the western blot hag was not being expressed. Also, when hag wasn't expressed the adherence went down significantly.

complete


See also

References

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