Cross-reactive carbohydrates

Mari, A., Iacovacci, P., Afferni, C. et al. 1999. Specific IgE to cross-reactive carbohydrate determinants strongly affect the in vitro diagnosis of allergic diseases. J Allergy Clin Immunol 103 1005-1011. 

Adedoyin J, Gronlund H, Oman H, Johansson SG, van Hage M Cat IgA, representative of new carbohydrate cross-reactive allergens. J Allergy Chn Immunol 2007 119 640-645. 26... 

One limitation of serum-specific IgE is that given the cross-reactivity between different Hymenoptera venoms, and also due to the presence of anti-carbohydrate antibodies, it is frequent to find several simultaneous positive results in patients with non-identified insect stings, a situation which makes diagnosis of the same difficult. In these cases, RAST inhibition and the release of histamine occasionally provide data on the venom involved and when this is not the case, it is advisable to administer immunotherapy against both [44]. 

Taken together, these results suggest that molecular recognition of the dodecapeptide by antibodies differs from its recognition by concanavahn A, and that the immunological cross-reactivity observed in some studies does not reflect structural mimicry. That molecular recognition by concanavalin A of carbohydrates and peptides differs has also been shown in structural studies. Here, the functional molecular mimicry observed with respect to different receptors should not be assumed to imply structural mimicry—the inter-molecular interactions may differ in each case. 

Wang, D., Liu, S., Trummer, B.J., Deng, C., and Wang, A., Carbohydrate microarrays for the recognition of cross-reactive molecular markers of microbes and host cells, Nat. Biotechnol20, 275-281, 2002. 

Studies on the white clover -Rhizobium trifolii interaction are the most advanced. Trifoliin A, a lectin present in clover-seedling roots, binds hapten reversibly to carbohydrate antigens cross-reactive on the capsular polysaccharide of R. trifolii and clover epidermal-cells.244 A specific hapten that inhibits binding of trifoliin A to both surfaces is 2-deoxy-D-arabino-hexose.245 It has also been shown that levels of trifoliin A on root hairs decline with increasing concentrations of nitrate, in parallel to root-nodule development,246 and that lectin receptors are transient on R. trifolii, in a way coinciding with its capacity to be adsorbed to clover roots.247... 

A large-scale enzymic synthesis of the trisaccharide a-D-Neu5Ac-(2—>3)-j8-D-Gal-( 1 — 3)-d-G1cNAc (65), the tumor-associated carbohydrate antigen CA 50, has been achieved.113 This is a further illustration of the cross reactivity and efficiency of STB, This sialyltransferase, like STA, was partially purified from porcine liver, according to a modification of Conradt s procedure. 114 The initial rate measured for j8-d-Gal-( 1 - 3)-d-G1cNAc at saturating concentration was 18% of the one measured for the real substrate / -d-... 

An example of a CILA using optical fibers has been described by Wang et al. [114] for the analysis of 6-mercaptopurine (6-MP). The template, 6-MP, was oxidized to a strong fluorescent compound by H202 in alkaline solution. Upon optimization of the H202 and NaOH concentrations and of the assay temperature, the sensor showed a linear response in the 1.0 x 10 s to 6.0 x 10 6 g mL-1 range with a detection limit of 3.0 x 10-9 g mL-1. Cross reactivity to metal ions, amino acids, and carbohydrates was tested and the sensor was applied to the analysis of 6-MP in spiked serum. 

Hayrinen I, Pelkonen S, Finne J. Structural similarity of the type-specific group B streptococcal polysaccharides and the carbohydrate units of tissue glycoproteins evaluation of possible cross-reactivity. Vaccine 1989 7 217-24. 

Perhaps the most interesting difference between the subunits is their carbohydrate-binding specificity.621,828 BS I(A4) agglutinated type A erythrocytes (specific titer, 170) but not type B cells, and precipitated A substance, indicating an affinity for a-D-linked 2-acetamido-2-deoxy-D-galactosyl residues. Cross-reactivity with a-D-galactosyl res-... 

B27, the HLA allele proposed to be involved in alkylosing spondylitis, shares an epitope with an enzyme from Klebsiella pneumoniae, a common intestinal Gram negative bacterium. Molecular mimicry is thought to result in cross-reactive antibody formation, joint inflammation and spinal damage. Along with many of the immunotherapies described for other similar arthritic autoimmune disorders, alkylosing spondylitis is treated with anti-inflammatory medications and a low carbohydrate diet to reduce intestinal K. pneumoniae levels. 

Nevertheless, the potential for autoimmune disease would clearly exist if one considers the polyspecificity of immune recognition molecules such as B cell receptors, antibodies, T cell receptors and MHC molecules. Further, the polyspecificity of immune receptors is also able to transcend the biochemically defined classes of biomolecules. For instance, the monoclonal antibody SYA/J6 has been demonstrated to have a dual specificity, binding a specific carbohydrate or a specific peptide with comparable affinity.68 Detailed analysis of the interatomic interactions between the antibody combining site and either the carbohydrate or the peptide antigens demonstrated that functional mimicry is possible without exact structural mimicry. This example underlines the case that it is not possible to predict with certainty whether the molecular surfaces of all potentially cross-reactive epitopes, whether of foreign or self molecules, will, or will not, be able to bind to a specific antibody. 

---