Detection of Haemophilus ducreyi lipooligosaccharide by means of an immunolimulus assay

Hansen, Eric J.; Lumbley, Sheryl R.; Saxén, Harri; Kern, Kevin; Cope, Leslie D.; Radolf, Justin D.

doi:10.1016/0022-1759(95)00118-t

Cited by 9 publications

(7 citation statements)

References 43 publications

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“…It should be noted, however, that the tandem repeats of the nucleotide tetramer CAAT which are present in the 5Ј region of the H. influenzae type b lex-1/lic2A gene (12,27) and which are involved in LOS phase variation in H. influenzae (27) are not present in lbgA. While the absence of these nucleotide repeats in lbgA does not preclude phase variation by H. ducreyi LOS epitopes, studies from this laboratory suggest that at least the LOS epitope defined by its reactivity with MAb 3E6 does not exhibit phase variation in H. ducreyi 35000 (26). Similarly, structural analyses of purified H. ducreyi LOS indicate that phase variation of H. ducreyi LOS epitopes is minimal (37,61,62).…”

Section: Discussionmentioning

confidence: 83%

Identification of tandem genes involved in lipooligosaccharide expression by Haemophilus ducreyi

et al. 1997

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Section: Discussionmentioning

confidence: 83%

Identification of tandem genes involved in lipooligosaccharide expression by Haemophilus ducreyi

et al. 1997

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“…No differences were observed. A Western blot probed with anti-LOS monoclonal antibody 3E6 (22,69) revealed that there were no major differences in reactivity between the LOS moieties of parent and mutant strains (data not shown). There were also no differences in growth in rich broth between parent (35000HP and FX517) and mutant (FX533 and FX534) strains (data not shown).…”

Section: Resultsmentioning

confidence: 98%

“…2 ϫ 10 8 CFU) were suspended in Laemmli sample buffer (10% glycerol, 5% ␤ME, SDS, 0.0025% bromophenol blue) and incubated with proteinase K (50 g/ml final concentration) for 1 h at 56°C (27), boiled for 1 min, and stored at 4°C. Approximately 5 l of this preparation was subjected to SDS-PAGE and silver stained according to the method of Tsai and Frasch (76) or subjected to Western blotting with monoclonal antibody 3E6 that reacts with purified LOS from H. ducreyi strain 35000HP (22,69).…”

Section: Strains and Mediamentioning

confidence: 99%

A Novel Lectin, DltA, Is Required for Expression of a Full Serum Resistance Phenotype inHaemophilus ducreyi

Leduc¹,

Richards

Davis

et al. 2004

Infect Immun

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Haemophilus ducreyi, the causative agent of chancroid, is highly resistant to the complement-mediated bactericidal activity of normal human serum (NHS). Previously, we identified DsrA (for ducreyi serum resistance A), a major factor required for expression of the serum resistance phenotype in H. ducreyi. We describe here a second outer membrane protein, DltA (for ducreyi lectin A), which also contributes to serum resistance in H. ducreyi. Isogenic dltA mutants, constructed in 35000HP wild-type and FX517 dsrA backgrounds, were more susceptible to the bactericidal effects of NHS than each respective parent, demonstrating the additive effect of the mutations. Furthermore, expression of dltA in H. influenzae strain Rd rendered this highly susceptible strain partially resistant to 5% NHS compared to a vector-control strain. Although primary basic local alignment search tool analysis of the dltA open reading frame revealed no close bacterial homologue, similarity to the ␤-chain of the eukaryotic lectin ricin was noted. DltA shares highly conserved structural motifs with the ricin ␤ chain, such as cysteines and lectin-binding domains. To determine whether dltA was a lectin, ligand blots and affinity chromatography experiments were performed. DltA was affinity purified on immobilized lactose and N-acetylgalactosamine, and N-glycosylated but not glycosidase-treated model glycoproteins bound DltA. These data indicate that DltA is a lectin with specificity for lactose-related carbohydrates (CHO) and is important for H. ducreyi serum resistance.

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“…Direct immunofluorescent testing of ulcer material using an H ducreyi-specific monoclonal antibody appears to be useful (8,9). Hansen et al (10) developed an antigen detection assay to detect H ducreyi lipooligosaccharide (LOS) using an LOSspecific monoclonal antibody and an adaptation of the limulus amoebocyte assay. The sensitivity and specificity of these antigen detection methods are 89% to 100%, and 63% to 81%, respectively (8).…”

Section: Antigen Detectionmentioning

confidence: 99%

The Laboratory Diagnosis of Haemophilus ducreyi

Alfa¹

2005

Canadian Journal of Infectious Diseases and Medical Microbiolog

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Chancroid is a sexually transmitted infection caused by Haemophilus ducreyi. This fastidious, Gram-negative coccobacilli dies rapidly outside the human host, making diagnostic testing using culture methods difficult. This genital ulcer infection is not common in Canada and, therefore, can often be misdiagnosed. The objective of the present paper is to provide practical approaches for the diagnosis of chancroid in Canadian patients where the prevalence of this infection is low. Issues related to sample collection, sample transport and available diagnostic tests are reviewed, and several alternative approaches are outlined. Although antigen detection, serology and genetic amplification methods have all been reported for H ducreyi, none are commercially available. Culture is still the primary method available to most laboratories. However, the special media necessary for direct bedside inoculation is often not available; therefore, communication with the diagnostic laboratory and rapid specimen transport are essential when chancroid is suspected.

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Detection of Haemophilus ducreyi lipooligosaccharide by means of an immunolimulus assay

Cited by 9 publications

References 43 publications

Identification of tandem genes involved in lipooligosaccharide expression by Haemophilus ducreyi

Identification of tandem genes involved in lipooligosaccharide expression by Haemophilus ducreyi

A Novel Lectin, DltA, Is Required for Expression of a Full Serum Resistance Phenotype inHaemophilus ducreyi

The Laboratory Diagnosis of Haemophilus ducreyi

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