Immune-assays

Technically, the addition of carbon-centered radicals to C-N double bonds is as yet of little if any importance. In the free-radical chemistry of DNA it plays, however, a considerable role in the formation of the C(5 )-C(8) linkage between the sugar moiety and the purines (Chap. 10.5). Because of its importance, even an immune assay has been developed for the sensitive detection of this kind of damage in DNA (Chap. 13.2). The addition of the C(5 ) radical to the C(8) position of a purine is obviously facilitated for steric reasons (formation of a six-membered ring), but the same kind of reaction also occurs as an intermolecular reaction. Since alkyl radicals are nucleophilic, the rate of this reaction is noticeably increased upon protonation of the purine (Aravindakumar et al. 1994 for rate constants see Chap. 10.5). 

Protein Expression Specific protein expression Antibody based assays (e.g. western blots, immunohistochemistry, immunofluorescence, enzyme immune assays, protein microarrays)... 

Effects on immune function, as indicated by altered responses in humoral and cell-mediated immunity assays and host resistance tests, were also induced by intermediate-duration oral exposure to commercial mixtures. Studies in nonprimate species showed reduced antibody responses to tetanus toxoid in guinea pigs exposed to Clopen A-60 (4 mg/kg/day for 3-5 weeks), keyhole limpet hemocyanin in rats exposed to Aroclor 1254 (4.3 mg/kg/day for 10 weeks), and SRBC in mice exposed to Aroclor 1242 (22 mg/kg/day... 

Another major problem that has plagued the field of thymic hormone research is that specific bioassays for thymic hormones are not available. Indeed, the thymic hormones have been aptly termed hormones in search of a bioassay (Bach and Carnaud, 1976). It is quite simple to add a thymic factor to a routine immune assay and look for a positive or negative influence. However, unless the target cell population for such studies is well defined, the results are likely to be difficult to interpret in terms of normal physiological mechanisms. This latter point no doubt explains many of the inconsistencies reported in the thymic hormone field. 

RDX in feed). During the 90-d feeding study, four females (three at 420 and one at 187 ppm) and one male (exposed to 420 ppm) died within 56 d of exposure. It is likely the exposures to 420 ppm are of consequence, and that the moribund individual at 187 ppm was an anomaly, particularly since there were no statistical differences in organ weights, body mass, egg production, hematology, histopathology, and various functional and descriptive immune assays that were also conducted as part of the 90-d study [44], The feed consumption rates and mean body masses resulted in calculated RDX intakes of 0,6.0, 8.7,10.6,12.4, and 18.4 mg RDX kg-1 bw d 1 for both sexes for the 0, 83,125,187, 280, and 420 ppm feed treatments, respectively. 

What could be done to better assess immunomodulatory effects in NHP that will be predictive of the outcome in humans One important consideration is the relevance of the animal species and the appropriateness and relevance of the immune assays being utilized. 

Fig. 8 Illustration of process involved in ECL immune assays based on magnetic microbeads as solid support. Reprinted with permission from Ref 19. Copyright (2008) Spinger.

Fig. 9 Three test modes for immune assays based on the Ru(bpy)3 /TPrA system adopted by commercial instrument, (a) competitive principle, (b) sandwich principle (c) bridging principle.

Benjamini E, Coico R, and Sunshine G (2000) Antigen-antibody interactions, immune assays, and experimental systems. In Immunology A Short Course, pp. 98-100. New York Wiley-Liss. 

Figure 8.11 Fabrication of a boronic acid based immune-assay sensor on a screen printed electrode platform. (Reproduced from ref. 83 with the permission of Elsevier.)...

Bioluminescent Enzyme Immune Assay (BLEIA), where the enzyme is the marker for the antigen of the immune reaction, which results in light emission. Markers are enzymes that are conjugated to bacterial luciferase, such as peroxidases, acid phosphatases and dehydrogenases. 

Bioluminescent Co-factor Immune Assay (BLCIA), in which ATP and NAD(P)H are very strongly linked to the marker molecules of the antigen. 

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