Antigens, cross-reaction with

Antigens, cross-reaction with cotton antibodies, 49 Avenalumins, 31f Azadirachtin... 

Figure 6.31 The basis of type I hypersensitivity reactions. The antigens cross-link with IgE antibodies, which are attached to mast cells.

Vojdani, A., Campbell, A.W., Anyanwu, E., Kashanian, A., Bock, K., Vojdani, E. 2002. Antibodies to neuron-specific antigens in children with autism possible cross-reaction with encephalitogenic proteins from milk, Chlamydia pneumoniae and Streptococcus group A.. / Neuroimmunol. 129, 168-177. 

The occurrence of cross-reactions with lysozymes of various species may contribute substantially to the precise delineation of the antigenic determinants. Turkey and bobwhite quail lysozymes differ from that of chicken in that Arg replaces Lys at positions 73 and 68, respectively. Turkey lysozyme reacted identically but quail lysozyme was weaker, thus indicating that Arg-68 makes a greater contribution to the interaction with the antibody combining site. 

Wide and his colleagues (W5, W7) were the first to apply the technique of hemagglutination-inhibition to the estimation of urinary LH. They found that some antisera raised against HCG were incapable of distinguishing between HCG and LH, and, accordingly, they were able to establish an assay system for LH using an antiserum raised to HCG and HCG-coated red blood cells. Taymor (T2) used a similar system to assay human urinary LH. He also employed an HCG antiserum and latex particles coated with this hormone the system was specific in that a cross reaction with ovine LH was not observed however, its specificity with respect to FSH was not reported. Taymor (T2) found it necessary to extract LH from urine prior to immunoassay. For this purpose he preferred precipitation with acetone to treatment with alcohol, since trace amounts of the latter interfered with the antigen-antibody reaction. 

To study the in vivo stability and immunoreactivity of the diabody, as well as to check for possible cross-reactions with the NCA-95 antigen expressed in granulocytes (an earlier study, outlined in Ref. [4.22], was carried out using scFv as the variant), a study of the biodistribution of d-ior-CEAl-(scFv)2 in healthy MNRI mice and in nude mice bearing LS174T human CEA positive tumours was carried out. 

The problem of cross reaction with other antigens is a complex one and must be considered separately for each type of antigen being measured. Special purification techniques may be required. 

This example shows that immunochemical methods are not neccessarily highly specific. Cross reactions with immunoprecipitable material or solubilization of antigen complexes can falsify the assay to a considerable extent. Currently more sophisticated techniques bearing a higher specifity than the older methods are employed They are used in many laboratories for routine purposes The most reliable... 

By use of different extraction procedures, two types of lipopolysaccharides have been isolated from a slightly virulent strain of Yersinia pestis Some structural information was obtained from methylation and periodate oxidation studies. The immunodominant moiety of lipid A has been shown to consist of a residue of 2-amino-2-deoxy-D-glucose, A-acylated with 3-hydroxytetradecanoic acid. ° A lipopolysaccharide isolated from Y. enterolitica exhibits serological cross-reactions with lipopolysaccharides from Brucella abortus and Vibrio cholerae Common antigenic relationships between the lipopolysaccharides of Escherichia coli, Kloechera africana, and Salmonella aberdeen have been demonstrated. 

Relatively stable proteins isolated from human heart and from human and rhesus monkey skeletal muscles, are capable of binding to /3-D-galactosides. Gel precipitation and radioimmunoassay studies with rabbit antiserum to calf heart lectin revealed antigenic cross-reactions between the primate and bovine muscle lectins. The lectin from calf heart shows a greater specificity towards the terminal disaccharide (lactosamine) units of blood-group antigen precursor chains than does the Ricinus communis lectin. 

The large spectrum of cross-reactions with different denatured DNAs is readily explained by the fact that the number of different bases involved in deoxynucleic acids is extremely limited and that the four major bases are composed of only two main classes, the purines and the pyrimidines. The absence of cross-reactions with native DNA has been attributed to the non-accessibihty of the antigenic sites, the bases lying in the interior of the doublehelical structure. 

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