Cross-reactivity of antibodies

Other potential problems include high background, nonspecific or weak cross-reactivity of antibodies, poor protein transfer or membrane binding efficiency, and insufficient sensitivity. For an extensive survey and discussion of immunoblotting problems and artifacts, see Bjer-rum et al. (1988). 

Cross-reactivity of antibodies to human antigens with identical or similar antigens of other species, or cross-species cross-reactivity, can be of interest to the researcher and veterinarian because of the scarcity of animal-specific antibodies. To overcome this, two publications reported the results of cross-species reactivity studies using commercially available antihuman polyclonal and monoclonal antibodies (10, 11). It was demonstrated that the majority of animal... 

Utility in a variety of species - activity as opposed to antigen mass is measured, so cross-reactivity of antibodies or probes across species is not a consideration... 

Figure 3. Cross-reactivity of antibodies toward chloroacetanilide herbicides and analogues of alachlor.

Tissue Biochain www.biochain.com Arrays or frozen tissne from 15 different species for determination of species cross-reactivity of antibodies. 

Radioimmunoassay. Antibodies can be produced against bile acid-protein complexes - usually bile acid-bovine serum albumin complex - and used for radioimmunoassay of that bile acid in usual manner (cf. 1). Each bile acid should have its own antibody so that the method is suitable for the quantitation of individual bile acids provided the antibodies are specific enough. One of the major problems actually is the cross-reactivity of antibodies and difficulties in the determination of total bile acids in biological materials. Thus, for the fec il bile acids with mainly bacterial transformation products (see Fig. 1) and to some extent for the urinary bile acids, especially under diseased conditions, this is quite Impossible. 

Specificity of the assay depends on the specificity (cross-reactivity) of the antibodies. Of the known cyanobacterial toxins, only hepatotoxins are detected and are, therefore, able to be screened for by protein phosphatase inhibition. 

Table 2 Cross-reactivity of racemic ractopamine and ractopamine glucuronide metabolites to a monoclonal antibody developed against racemic ractopamine...

The affinity and cross-reactivity of the whole serum and Fab fragments were determined using equilibrium dialysis for the affinity determination and RIA for the cross-reactivity studies. The average intrinsic affinity constant (Ko) of the antibody (Nisonoff and Pressman 1958) changed very little throughout the... 

Figure 4. DDC (A), serotonin (B), and tyrosine hydroxylase (C) immunore-activity in the posterior region of a wild-type Drosophila ventral ganglion. Tyrosine hydroxylase (TH) encodes the rate-limiting step in dopamine biosynthesis and is a marker for dopamine cells. B and C are the same CNS assayed for both serotonin and TH. M, medial dopamine neurons VL, ventrolateral serotonin neurons DL, dorsolateral dopamine neurons. Short unmarked arrows in C show vacuolated cells that do not contain DDC immunoreactivity. The immunoreactivity in these cells may represent a nonspecific cross-reactivity of the rat TH antibody. The length bar in A is 50 pM. The images are confocal projections generated on a Molecular Dynamics-2000 confocal laser scanning microscope.

A special nonspecific sensor response might be due to the cross-reactivity of immobilized antibodies. Besides the analyte, an antibody can bind also other entities bearing a similar antigenic epitope, e.g. the detection of some pathogenic bacteria can be interfered by the binding of non-pathogenic bacteria with the same surface antigen. 

Donohue-Rolfe, Arthur, David W.K. Acheson, Anne V. Kane, and Gerald T. Keusch. "Purification of Shiga Toxin and Shiga-Like Toxins I and II by Receptor Analog Affinity Chromatography with Immobilized PI Glycoprotein and Production of Cross-Reactive Monoclonal Antibodies." Infection and Immunity 57 (December 1989) 3888-893. 

Lymphocytes, the effector cells of the acquired immune system, include morphologically indistinguishable T and B cells, the former divided into CD4+ T helper cells and CD8+ cytotoxic T cells. Since the functions of those cell subsets differ so drastically, it became important to develop tools to distinguish them from each other. Efforts to identify cell subsets according to their expression of different surface antigens have been successful, including various Cluster of Determination (CD) markers (Table 23.1). In addition, cross-reactive monoclonal antibodies, and subsequently developed species-specific polyclonal and monoclonal antibodies towards the major histocompatibility complex (MHC) have been used to label cells in circulation and in tissue sections (Table 23.1). 

Jaber, J.R. et al., Cross-reactivity of human and bovine antibodies in striped dolphin paraffin wax-embedded tissues, Vet. Immunol. Immunopathol., 96, 65, 2003. 

Recently, a novel immunoassay has been developed for the quantitative determination of polybrominated biphenyls using indirect competitive format. The new method was optimized concenung the coating conjugate and antibody concentration, incubation time and temperature, the tolerance to organic solvents and so on. Under optimized conditions, PBB15 can be determined in the concentration range of 0.01-100 pg/L with a detection hmit of 0.02 pg/L. The cross-reactivities of the assays were below 8%. While water samples could be analyzed directly [94]. 

Koshte, V. L., Kagan, S. L., and Aalberse, R. C. (1989). Cross-reactivity of IgE antibodies to caddis fly with arthropoda and mollusca. /. Allergy Clin. Immunol. 84,174 183. 

The principal limitation of these data is the lack of definition of the individual forms for the CYP2C subfamily. Analysis of this subfamily has remained problematic due to high cross-reactivities of all of the distinct forms with most antibody preparations. In addition, Western blot analysis does not distinguish between active and inactive forms of the protein. Furthermore, distinct enzymes may have different affinities for coenzymes necessary for catalytic activity, which will serve to unlink abundance of the protein and its catalytic activity. Therefore the assumptions must be made that the ratios of active to inactive protein are similar for all forms and that all forms have similar affinities for coenzymes. These assumptions may not be justified. However, even with these limitations, the study of Shimada et al. (1994) contributes greatly to our understanding of relative enzyme abundance in human liver. In addition, the relative abundance data, coupled with the absolute P450 content (per unit protein) and the turnover numbers for enzyme-specific substrates (per unit protein), can provide an estimate of the turnover number for individual enzymes in the human liver membrane environment. This provides an important benchmark for evaluation of turnover number data from cDNA-expressed enzymes. 

The linear polysaccharides have been used in a number of immunological reactions. The linear D-mannan was found to confer cutaneous activity in guinea pigs to a dermatophyte polysaccharide.136 It was, however, found to be non-cross-reactive with antibodies to yeast D-mannan,137-138 and antibodies to linear D-mannan were not cross-reactive to yeast D-mannan.138 Anti-linear-D-mannan antibodies have been... 

---