Cross-reacting determinant

Zhao Z, Baldo BA, Rimmer J beta-Lactam allergenic determinants fine structural recognition of a cross-reacting determinant on benzylpenicillin and cephalothin. 

Cross reacting determinant (CRD) activity in the phosphoinositolglycan liberated by PI-PLC... 

CRD cross-reacting determinant IPG inositol phosphate glycan... 

Bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) (reviewed in ref. [51]) or trypanosomal GPI-specific phospholipase C (GPI-PLC) [52-54] releases GPI-anchored proteins from the cell surface leaving behind diacylglycerol. This cleavage not only solubilizes the protein, but also exposes a phosphoinositol-containing cryptic epitope termed cross-reacting determinant [55]. Reactivity of polyclonal antibodies derived against the cross-reacting determinant (CRD) provide additional evidence for the presence of a GPI anchor. 

Data to be summarized here suggest that there are two kinds of idiotypic determinants in myeloma proteins. The first type cannot be detected in nonspecific immunoglobulin, even with extremely sensitive techniques. The second is apparently present in the nonspecific population however, it is not certain whether the cross-reacting determinants are identical or only related in structure. 

Moller, M., Kayma, M., Vieluf, D., Paschke, A., and Steinhart, H. (1998). Determination and characterization of cross-reacting allergens in latex, avocado, banana, and kiwi fruit. Allergy 53,289-296. 

Structurally related compounds may cross-react with the antibody, yielding inaccurate results. In screening for the herbicide alachlor in well water by immunoassay, a number of false positives were reported when compared with gas chromatography (GC) analysis. A metabolite of alachlor was found to be present in the samples and it was subsequently determined that the cross-reactivity by this metabolite accounted for the false-positive results. On the other hand, cross-reactivity by certain structural analogs may not be an issue. For example, in an assay for the herbicide atrazine, cross-reactivity by propazine is 196% because of atrazine and propazine field use... 

Shelver and Smittf confirmed fhaf commercial clenbuterol immunoassays cross-react with some, but not all, clenbuterol metabolites. As a result, quantitative clenbuterol immunoassays may differ from determinative methods if substantial concentrations of metabolites are present. For clenbuterol, the parent clenbuterol level is... 

Kennedy et al. developed a lasalocid immunoassay for application to residues in chicken meat and liver samples. The antibody was specific and did not cross-react with salinomycin, maduramicin, or monensin. Sample preparation consisted of homogenization in aqueous acetonitrile, removal of fat from an aliquot of the aqueous acetonitrile by hexane extraction, and evaporation of acetonitrile. The sample was then reconstituted with assay buffer. Liver required an additional solid phase extraction step. The LOQ was 0.02 xgkg for muscle and 0.15 agkg for liver. These workers were able to use the system to determine the half-life of lasalocid in the tissues. 

While invertebrate tropomyosins are likely pan-allergens, vertebrate tropomyosins appear to be nonallergenic (Reese et ah, 1999). Using bioinformatics approaches to compare the sequences of tropomyosins from various species, Goodman et ah (2002) determined that tropomyosins from vertebrate species — rabbit, pig, chicken, and human — share 53-57% amino acid sequence identity to the known shrimp tropomyosin allergen. Met e 1. This comparison likely explains why vertebrate tropomyosins are not allergenic and do not cross-react with IgE antibodies specific to invertebrate tropomyosins. 

The degree of specificity of the MAB may also present other disadvantages in assay development for some antigens. For instance, MABs to viral strains may be so specific that they do not cross-react with other minor strains of the same virus. The mixed response of polyclonal antibodies is likely to be directed to several antigenic determinants, one or more being present on each strain. 

This section considers the cross section for reactive collisions ar. Bimolecular reactions will be treated explicitly. The rate (frequency) of collisions depends on the collision cross section. The larger the cross section, the more often molecules run into one another. In a similar way the reactive cross section determines how often molecules run into one another and react. This section introduces the simple line-of-centers model for scaling of the reactive cross section with energy. 

The first step in developing an ELISA to detect the stem peptide product of the coupled enzyme reaction was to determine if antibodies to the stem peptide could be raised in animals. Only small quantities of stem peptide could be isolated or prepared enzymatically, so we used the commercially available pentapeptide portion of the stem peptide as the hapten in the hopes of generating high-affinity antibodies that would cross-react with the stem peptide. 

---