OvGalBP, a filarial antigen with homology to vertebrate galactoside-binding proteins.

Abstract

The increased incidence of "allergic" symptomatology and clinical complications seen in non-endemic individuals with loiasis, as compared to natives of endemic areas, is thought to reflect a heightened immune response to filarial antigens. To identify antigens involved in this hyperresponsiveness, a cDNA library constructed from adult female RNA from the related filarial parasite, Onchocerca volvulus, was screened with serum from a North American who acquired loiasis in West Africa. Sequence analysis of one of the identified clones, OvGalBP, revealed significant homology to the vertebrate S-type lectins, a family of thiol-dependent, metal-independent galactoside binding lectins, which includes an IgE-binding protein thought to be involved in IgE regulation. The 1100-bp insert of OvGalBP contains the entire protein coding region and has a 3' poly(A) tail. The two amino acid consensus sequences (WGxExR and HFNPRF) found in all of the S-type lectins are present. Purified recombinant protein expressed as a fusion with glutathione-S-transferase (OvGalBP-GST) was recognized by sera from a majority of filaria-infected patients but not by putatively immune individuals from an endemic area or by unexposed endemic and non-endemic controls. Interestingly, OvGalBP-GST specifically bound IgE (and not IgG) in a lactose-inhibitable manner, suggesting a potential role for this protein in the pathophysiology of human filarial infection.

• Authors: A D Klion, J E Donelson
• Journal: Molecular and biochemical parasitology (Mol Biochem Parasitol) Vol. 65 Issue 2 Pg. 305-15 (Jun 1994) ISSN: 0166-6851 [Print] Netherlands
• PMID: 7969271 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Helminth
• Antigens, Helminth
• Calcium-Binding Proteins
• Carrier Proteins
• Monosaccharide Transport Proteins
• Periplasmic Binding Proteins
• Recombinant Fusion Proteins
• galactose-binding protein
• Immunoglobulin E
• Galactose

Topics

• Amino Acid Sequence
• Animals
• Antibodies, Helminth (isolation & purification)
• Antigens, Helminth (chemistry, genetics)
• Base Sequence
• Calcium-Binding Proteins
• Carrier Proteins (chemistry, genetics, immunology)
• Female
• Galactose (chemistry, genetics, immunology)
• Gene Expression Regulation
• Humans
• Immunoglobulin E (isolation & purification)
• Loiasis (immunology)
• Molecular Sequence Data
• Monosaccharide Transport Proteins
• Onchocerca volvulus (immunology)
• Onchocerciasis (immunology)
• Periplasmic Binding Proteins
• Recombinant Fusion Proteins (chemistry, genetics, immunology)
• Sequence Homology, Amino Acid