Antigens detection

Rapid antigen detection test 80% to 90% sensitivity results within minutes... 

FIGURE 69-5. Treatment algorithm for management of pharyngitis in children and adults.45,46 aRapid antigen detection tests (RADTs) are preferred if the test sensitivity exceeds 80%. 

Diagnostic tests for amebiasis include stool for ova, antigen detection, or polymerase chain reaction (PCR) testing. 

Sensitive techniques are available to detect E. histolytica in stool antigen detection, antibody test (ELISA) and PCR. 

Laboratory confirmation is vital to effective treatment of HSV, especially in individuals in whom a clinical diagnosis cannot be obtained. There are several methods by which a definitive diagnosis may be acquired, and these include virologic typing, serologic diagnosis, rapid point-of-care antigen detection, enzyme-linked immunosorbent assay (ELISA), immunoblot, and DNA polymerase chain reaction.27... 

Clinical correlation studies between CA 27.29 levels and CA 15-3 levels typically yield correlation coefficients of >0.95. It has been suggested that the epitope mapping studies reflect that the CA 27.29 antigen is essentially the same breast cancer-associated mucinous antigen detected by the two methods. 

La Scolea, L. Diagnosis of paediatric infections using bacterial antigen detection systems. Clin. Microbiol. Newsletter 1998,10,21-23. 

Most immunodiagnostic tests used today for parasitic infections detect antibody. In recent years, the sensitivity and specificity of many such tests have improved. A number of antigen detection tests have recently been described and show promise, but none of these tests are currently available commercially. 

Stichocyte development p43 synthesis Nuclear antigen detection... 

A common application for (strept)avidin-biotin chemistry is in immunoassays. The specificity of antibody molecules provides the targeting capability to recognize and bind particular antigen molecules. If there are biotin labels on the antibody, it creates multiple sites for the binding of (strept)avidin. If (strept)avidin is in turn labeled with an enzyme, fluorophore, etc., then a very sensitive antigen detection system is created. The potential for more than one labeled (strept)avidin to become attached to each antibody through its multiple biotinylation sites is the key to dramatic increases in assay sensitivity over that obtained through the use of antibodies directly labeled with a detectable tag. 

Throat swab and culture or rapid antigen detection testing. 

The majority of rapid antigen-detection tests available have a specificity >95% (minimizes ATI... 

Antigen Detection on Tissues Using Primary Antibody... 

If possible, your primary antibody should not be raised in the same species as the tissue under study, since antigen detection with the use of antibodies on... 

Avidin-biotin complex (ABC) is based on the high affinity that streptavidin (from Streptomyces avidinii) and avidin (from chicken egg) have for biotin. Biotin is a naturally occurring vitamin. One mole avidin will bind four moles biotin. ABC method affords a several-fold higher antigen detectability than those achieved in the standard indirect method. 

Maximal levels of IL-1 /3 mRNA are detected within 1 h exposure to GM-CSF levels then decline to about 50% of maximal by 2 h and then fall to near base-line levels by 8 h (Fig. 7.10). Similarly, levels of IL-1 j8 protein are transiently expressed, broadly following the changes in mRNA levels. Thus, levels of antigenically-detectable protein are maximal by 2-4 h (in cell extracts) and are detected extracellularly in the culture medium by 4 h. Whilst IL-1 (IL-1 a and IL-1/) at 1 ng/ml) and TNF (at 5 ng/ml) are capable of stimulating an increase in IL-1/) mRNA levels, they can synergise with... 

After electrophoresis, protein bands are transferred onto a solid support. Many aspects of a transfer can affect antigen detection. Some of these factors are specific to the transfer method and choice of membrane, whereas others apply to the entire blotting procedure. For example, the transfer efficiency may be affected by the presence of SDS in the gel and whether the gel was stained prior to transfer. 

All detection systems can be employed following HER and noticeable improvement of most antigen detection will be observed. However, we recommend using sensitive detection systems, such as streptavidin-biotin-peroxidase methods when antigen density is low. 

Overview of Antigen Detection Through Enzymatic Activity ... 

The above represent the past and present of the most common enzyme-mediated methods of antigen detection. There are alternate procedures available, involving such methods as antibiotin antibody steps that combine the avidin-biotin systems with a further antibiotin/antienzyme sandwich for still greater sensitivity. Also, there are methods that follow a PAP procedure with a biotinylated antibody to the PAP immunoglobulin followed by ABC detection (15). The obvious problem created with this approach is the tremendous... 

The second strategy uses combinations of different antibodies coupled to fluorochromes with distinct emission maxima (5,9). The most relevant fluoro-chromes for combined antigen detection are fluorescein isothiocyanate (FITC abs. max. 494 nm, emiss. max. 517 nm), rhodamine isothiocyanate (TRITC ... 

The wide range of chromogenic-substrate systems available allows one to obtain excellent color contrast for double/multiple antigen detection. Chromo-genie reactions resulting in black (IGSS), yellow-brown (IPO/DAB), red-brown (IPO/AEC), blue (lAP/Fast Blue, or 5-bromo-4-chloro-3-indolyl phosphate/ nitroblue tetrazolium [BCIP-NBT]), and purple (lAP/Fast Red or New Fuchsin) can be used in different combinations (see Chapter 23). For development of these products, the following protocols are provided (see Note 16). 

Double labeling with IGSS and IPO may be followed by the detection of a third antigen consecntively with an indirect lAP method as detailed above. Recommended combinations for seqnential triple antigen detection are ... 

Dill, K., Montgomery, D.D., Wang, W., and Tsai, J.D., Antigen detection using microelectrode array microchips, Clin. Chim. Acta, 444, 66-78, 2001. 

Schweitzer, B., Wiltshire, S., Lamber, J., O Malley, S., Kukanskis, K., Zhu, Z., Kingsmore, S.E, Lizardi, F.M., and Ward, D.C., Immunoassays with rolling circle DNA amplification a versatile platform for ultrasensitive antigen detection, Proc. Natl. Acad. Sci. USA, 97, 10113-10119, 2000. 

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