Article

A Haemophilus influenzae strain associated with Fisher syndrome expresses a novel disialylated ganglioside mimic.

Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada.
Biochemistry (impact factor: 3.42). 08/2007; 46(27):8164-71. DOI:10.1021/bi700685s pp.8164-71
Source: PubMed

ABSTRACT The non-typeable Haemophilus influenzae strain DH1 was isolated from a 25 year old male patient with Fisher syndrome, a postinfectious autoimmune condition characterized by the presence of anti-GQ1b IgG antibodies that target and initiate damage to peripheral nerves. DH1 was found to display an alphaNeuAc(2-8)alphaNeuAc(2-3)betaGal branch bound to the tetraheptosyl backbone core of its lipooligosaccharide (LOS). The novel sialylation pattern was found to be dependent on the activity of a bifunctional sialyltransferase, Lic3B, which catalyzes the addition of both the terminal and subterminal sialic acid residues. Patient serum IgGs bind to DH1 LOS, and the reactivity is significantly influenced by the presence of sialylated glycoforms. The display by DH1, of a surface glycan that mimics the terminal trisaccharide portion of disialosyl-containing gangliosides, provides strong evidence for its involvement in the development of Fisher syndrome.

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Keywords

25 year old male patient
 
alphaNeuAc(2-8)alphaNeuAc(2-3)betaGal branch
 
anti-GQ1b IgG antibodies
 
bifunctional sialyltransferase
 
disialosyl-containing gangliosides
 
Fisher syndrome
 
lipooligosaccharide
 
non-typeable Haemophilus influenzae strain DH1
 
peripheral nerves
 
postinfectious autoimmune condition
 
sialylated glycoforms
 
strong evidence
 
subterminal sialic acid residues
 
surface glycan
 

R Scott Houliston