Immunological assays

The best human data available on immune response involve small numbers of subjects and lack of adequate controls. Additional studies on immune function parameters in both children and adults are needed to verify or refute the lack of immunotoxicify seen in humans to date. These studies should include a well defined set of immunologic assays in order to facilitate comparisons between studies. 

In the future, it is likely that many labor-intensive functional immunological assays performed in vivo or ex vivo will be replaced by high throughput multiparameter cytometric-based assays. The challenges faced both today and in the future have been recently described.56 For example, translational aspects of the nonclinical data to the clinical setting are difficult because despite much similarity, there are still species differences in some of the very basic aspects of the immune system. Additionally, reagents... 

The main features of the immunological assays for Lp(a) quantification are summarized in Table 5. RIA and ELISA assays are among the most sensitive, while RID and EIA are less sensitive and less suited to the measurement of low Lp(a) levels. The reference values reported for Lp(a) are lowest with the EIA techniques and highest with the turbidimetric assays (R15). 

In addition to peroxidase-mediated immunologic assays, there are also alkaline phosphatase-anti alkaline phosphatase (APAAP) reagents available (12). The general overall principle governing these immunologic assays remains the same. 

The classical microbial assay approaches to measuring antibiotic residues, diffusion, turbidimetric and acid production were described and the advantages and limitations reviewed. Other systems so discussed and reviewed were the affinity or receptor methods and the immunological approach using ELISA or EMIT assay techniques. The classical systems, in general, could measure antibiotic residues at the fractional ppm to the ppb levels. The potentials of the receptor and immunological assay system were discussed. 

Microbiologically based assay systems invariably measure the active antibiotic(s) or forms of the antibiotic that can be inhibitory to microorganisms. Immunological assays can measure both the active antibiotic as well as microbiologically inactive species. 

Immunological assays measure those moieties that can cause an antigenic response. For the most part, immunological assays should not be interfered with by antibiotics from the other antibiotic families, the specificity of the antibodies being vaguely similar to the specificity of enzyme systems. 

Several successful attempts were done to transfer classical CEIA to a microchip-based format. This kind of miniaturization is a trend that can overcome the limitations of CE in high-throughput systems. On-chip CE offers both parallel analysis of samples and short separation times. Koutny et al. showed the use of an immunoassay on-chip (32). In this competitive approach fluorescein-labeled cortisol was used to detect unlabeled cortisol spiked to serum (Fig. 8). The system showed good reproducibility and robustness even in this problematic kind of sample matrix. Using serum cortisol standards calibration and quantification is possible in a working range of clinical interest. This example demonstrated that microchip electrophoretic systems are analytical devices suitable for immunological assays that can compete with common techniques. 

Because of the requirement to use radioactive substances, RIAs are frequently being replaced by other immunologic assays, such as ELISA and fluorescence polarization immunoassays (FPIA) (Niemann et al. 1985). These have similar degrees of sensitivity. FPIAs are highly quantitative, as are RIAs, and ELISAs can be designed to be quantitative. 

Among the many immunological assay methods, the enzyme-linked immunosorbent assay methods (ELISA) are the most popular methods. ELISA can detect both antigen molecules and antibody molecules with only a slight modification of the procedure. The direct-binding and sandwich methods that are used for the... 

Because of the increase in the number of samples and the need for high-sensitivity detection, high-throughput, and high-sensitivity immunological assay... 

The multivalency of peptide dendrimers has also been used to increase the binding avidity of antigens to antibodies in various immunological assays and diagnostic tests. 27,43,47,48,55-59 Examples in the literature have been reported where the MAP format increases the binding avidity and sensitivity, in some cases >100000 fold. In addition to immunology, MAP types of dendrimers have found applications in areas such as inhibitors, 44,45,51,60,61 artificial proteins, 62 affinity purification, 63 and intracellular transportation, 41 as well as in drug discovery. 53 ... 

Methods for Biomarkers of Exposure. No methods were located for measuring any biomarkers of exposure to BCME. Although covalent adducts of BCME with cellular proteins or DNA have not yet been reported, development of sensitive and specific immunological assays for such adducts would provide a valuable means of detecting and perhaps quantifying human exposure levels. 

In these cases, a competitive immunological assay was used. Briefly, the three-step experimental procedure consists of (i) immobilization... 

In the previous pages we have described, in principle, an immunological assay for the quantification of limonin and naringin in citrus mples. In these assays we have employed radioactive tracers ( I and H) and have found that both are useable in a... 

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