Natural antibodies to nematode biotinyl-enzymes in human sera

Abstract

Biotinyl-enzymes are conservative molecules present in helminths, as well as in other animals, bacteria and plants. They have recently been found to be antigenic in mice, and a potential source of cross-reactivity among helminths. This study investigated the presence in human sera of antibodies reactive with biotinyl-enzymes from the nematodes Anisakis simplex, Toxocara canis and Ascaris suum. Biotinyl-enzymes from all these nematodes were recognized by IgG1 antibodies in sera from healthy subjects and from Anisakis-free patients infected with other parasites. Interestingly, IgE antibodies reactive with Anisakis simplex biotinyl-enzymes were present in about one third of the sera from Anisakis-free patients infected with other parasites. Our results also demonstrate that the anti-BE IgG1 and IgE antibodies present in the sera of Anisakis-free subjects are cross-reactive among helminths. We conclude that biotinyl-enzymes from nematodes are recognized by natural human antibodies, although Anisakis biotinyl-enzymes do not seem to be the cause of sensitization. Since sera from the Anisakis-free population also present these antibodies, as-yet unidentified factors (dietary components, intestinal inflammation and/or the presence of parasites) may contribute to the induction of anti-BE antibody background.

Immunoglobulin E-Mediated Autoimmunity

“…Most of these natural antibodies belong to the isotypes IgM, IgG 3 , and IgA, and these unspecific antibodies, even if they can bind to self-antigens, are thought to be protective, rather than harmful ( 119 , 120 ). There is also some published evidence for the existence of natural IgE antibodies against pancreatic cancer cells ( 121 ) and conserved biotinylated-enzyme molecules present in many organisms, such as Anisakis simplex, Toxocara canis, Ascaris suum , and Culex quinquefasciatus ( 122 , 123 ). While there are currently no data available on the role and relevance of natural IgE antibodies and how they could affect disease activity, there is some published evidence for a role of antigen-specific IgE against self in different diseases.…”

Common Symptoms from an Uncommon Infection: Gastrointestinal Anisakiasis

“…Therefore it is hypothesized that the live larva secretes proteins that induce allergic type reactions in subjects and induce significant clinical symptoms. In addition, it is difficult to interpret since Anisakis proteins demonstrate considerable immunological cross-reactivity to proteins of related nematodes [ 3 , 66 , 69 , 70 ]. Routine laboratory examination including leukocytosis, C-reactive protein, and peripheral eosinophilia may be helpful but these are not specific to this disease [ 38 , 71 ].…”

Seroreactivity to Anisakis spp. in the perinatal period

“…Another issue was the risk of cross-reactivity with some antigens. [16][17][18] After exhaustive repetition of the methods, careful work with the antigens, fine plate preparation, and assessment of the sensitivity and specificity of the antibody, we reached a consensus that reactivity on ELISA would be attributable to contact with Anisakis spp.…”