Competitive Binding Enzyme Immunoassay Research Articles

Blood Corticosterone Concentration Reaches Critical Illness Levels Early During Acute Malnutrition in the Weanling Mouse

Acute (i.e., wasting) pediatric malnutrition consistently elevates blood glucocorticoid levels, but neither the magnitude of the rise in concentration nor its kinetics is clear. Male and female C57BL/6J mice, initially 19 days old, and CBA/J mice, initially 23 days old, consumed a complete purified diet either ad libitum (age-matched control) or in restricted daily quantities (mimicking marasmus), or they consumed a purified isocaloric low-protein diet ad libitum (mimicking incipient kwashiorkor). Serum levels of corticosterone were assessed by double antibody radioimmunoassay after 3, 6, and 14 days (C57BL/6J strain) or after 6 and 14 days in the genetically distant CBA/J strain. Age-matched control groups of both strains exhibited mean corticosterone levels of 5-30 ng/ml, whereas the acutely malnourished groups exhibited mean levels of this hormone that were elevated by more than an order of magnitude as early as 3 days after initiation of weight loss. This outcome was confirmed in a second experiment in which the serum corticosterone level of C57BL/6J weanlings was examined by competitive binding enzyme immunoassay 3 and 14 days after initiation of the dietary protocols. Therefore, deficits of protein and/or energy in weanling murine systems relevant to acute pediatric malnutrition elicit early elevations in blood glucocorticoid levels to a magnitude reminiscent of critical illness and multiple trauma. The key to this novel finding was an exsanguination method that permitted accurate assessment of the blood corticosterone level of the healthy, quiescent mouse. Overall, the results of this investigation provide a new perspective on the glucocorticoids as part of the early hormonal response to acute weanling malnutrition coincident with the shift toward catabolic metabolism and the initiation of depression in cellular immune competence.

Evaluation of a Commercial Anti-Delta EIA Kit for Detection of Antibodies to Hepatitis Delta Virus

Anti-hepatitis delta virus (anti-HDV) antibodies were measured by solid phase IgG and IgM capture radioimmunoassays (RIA) as well as by a competitive binding enzyme immunoassay (EIA) in both acute and chronic HDV infections. EIA anti-delta test measures total delta antibody without discriminating IgM from IgG anti-delta. Low titer IgG antibodies were detected by both techniques with equal sensitivity. High titer IgG antibodies reached the end point sooner with EIA than with RIA (10(-3) versus greater than 10(-6)). When IgM anti-HDV was present without accompanying IgG anti-HDV, EIA failed to identify the antibody. Presence of high titer rheumatoid factor in the serum and lipemic samples produced false-positive results by EIA. Usage of undiluted serum samples for EIA probably exaggerates the factors contributing to false-positive reaction.

Competitive binding enzyme immunoassay for zonisamide, a new antiepileptic drug, with selected paired-enzyme labeled antigen and antibody

We assessed the competitive binding between zonisamide (ZNS) in serum samples and beta-galactosidase-labeled ZNS derivatives, using competing antibodies to ZNS derivatives, and selected the best enzyme-labeled antigen and antibody for accurate enzyme immunoassay (EIA) of ZNS in serum without interference from its metabolites or from other antiepileptic drugs. This EIA, based on use of antibody linked to bacterial cell walls, has advantages over HPLC in simplicity, speed (50 samples per hour), and lack of requirement for special equipment. The concentrations of ZNS in serum as measured by the EIA correlated well with those by HPLC (n = 33, r = 0.977).

Application of two monoclonal antibodies to either an immunosorbent enzyme assay or a competitive binding enzyme immunoassay for human serum pancreatic lipase

Application of two monoclonal antibodies to either an immunosorbent enzyme assay or a competitive binding enzyme immunoassay for human serum pancreatic lipase

Monoclonal Antibodies to the E1 and E2 Glycoproteins of Sindbis Virus: Definition of Epitopes and Efficiency of Protection from Fatal Encephalitis

Protection of mice from fatal neuroadapted Sindbis virus encephalitis can be accomplished by passive transfer of monoclonal antibodies (MAbs) to either the E1 or E2 glycoprotein of Sindbis virus. Both neutralizing and non-neutralizing MAbs can be protective. To define further the characteristics of MAbs that provide protection from fatal disease, antigenic epitopes on the E1 and E2 glycoproteins were identified using a competitive binding enzyme immunoassay. Four distinct epitopes on E1 and three on E2 were defined. MAbs to all E1 epitopes, both neutralizing (three) and non-neutralizing (one) protected mice from fatal encephalitis. MAbs to the E2 neutralizing epitopes (two) protected mice from fatal encephalitis while those to the non-neutralizing epitope did not. The efficiency of protection from fatal Sindbis virus encephalitis of four neutralizing and non-neutralizing protective anti-E1 and anti-E2 MAbs representing different epitopes was compared. The neutralizing MAbs (against epitopes E2-ab, E2-c and E1-c) gave 50% protection at lower doses (2 to 20 micrograms) than the non-neutralizing MAb representing epitope E1-e (150 micrograms) when given before virus challenge. When given after virus challenge, MAbs to E2-ab and E2-c protected at lower doses (0.03 to 0.3 micrograms) than did either MAbs to E1-c (greater than 100 micrograms) or E1-e (10 micrograms). The MAbs to E1-e, E2-ab and E2-c were required in larger amounts to afford protection before than after challenge, while the opposite was true for MAb to E1-c.

Simple enzyme immunoassay methods for recombinant human tumor necrosis factor α and its antibodies using a bacterial cell wall carrier

We have developed simple methods for measuring recombinant human tumor necrosis factor α (rHu-TNFα) and antibodies to rHu-TNFα in the sera of animals intravenously injected with rHu-TNFα. rHu-TNFα was measured by a competitive binding enzyme immunoassay (C-EIA) using standard rHu-TNFα, β-galactosidase labeled rHu-TNFα as enzyme-labeled antigen (E-Ag) and anti-rabbit IgG goat immunoglobulins coupled to bacterial cell walls (insolubilized second antibody). In contrast, anti-rHu-TNFα antibodies were measured by a sandwich EIA (S-EIA) using purified anti-rHu-TNFα rabbit IgG as standard, β-galactosidase labeled rHu-TNFα as E-Ag, and rHu-TNFα coupled to bacterial cell walls as insolubilized antigen. C-EIA permits the determination of serum rHu-TNFα within the range of 2–150 U/ml (about 0.7–52 ng/ml) with a CV of below 7.6% and 99% recovery. S-EIA permits the determination of anti-rHu-TNFα antibodies within the range of 70–1000 ng/ml with a CV of less than 4% and 94.8–106.9% recovery.

Standardization of antigen E in ragweed pollen extracts using a monoclonal antibody-based enzyme immunoassay

A hybridoma-derived monoclonal IgG antibody specific for ragweed AgE was used to develop a competitive binding enzyme immunoassay suitable for quantitation of antigen E levels in ragweed pollen extracts. The assay was capable of detecting as little as 30 ng/ml AgE in crude pollen extracts. The monoclonal antibody was shown to react with AgE present in commercial pooled pollen extracts from a number of ragweed species as well as a laboratory extract from a single species. In contrast to previous conventional xenoantisera, it could distinguish true ragweed ( Ambrosia sp) from false ragweed ( Franseria sp). The use of monoclonal antibodies in assay systems such as this offers a reproducible and widely applicable method for allergen standardization.

Determination of Lower Levels of Digoxin by Competitive Binding Enzyme Immunoassay (a Modified MARKIT® Method)

Optimal digoxin therapy has been facilitated by the development of an enzyme immunoassay (EIA) kit for digoxin by monitoring its blood concentrations. Clinically, there were some cases responsive to digoxin at the serum level of 0.3 ng/ml or less. However, at present, no EIA kit can determine such concentrations accurately and precisely. Thus, we conducted astudy on the determination of the lower levels of digoxin by a modified MARKIT method (one of the competitive binding EIA) by using a dilution method of antibody. The results showed that the modified MARKIT method can be clinically used for an accurate and precise (CV 10%) determination of the serum digoxin levels of 0.1 to 2.0ng/ml.

Determination of Antiepileptic Drugs in Body Fluid by a Competitive Binding Enzyme Immunoassay and Clinical Application

A competitive binding enzyme immunoassay (MARKIT) procedure for determination of the concentration of antiepileptic drugs was assessed and compared with gas-liquid chromatographic (GLC) procedures. Furthermore the Possibility of antiepileptic drugs determination in serum ultrafiltrate and mixed saliva was investigated with MARKIT. The two methods of MARKIT and GLC gave essentially the same results in determination of the serum levels of phenobarbital. The correlation coefficient of MARKIT between GLC was as high as 0.922. The recovery of the phenytoin in serum, serum ultrafiltrate and saliva were 98.1±1.9, 97.5±2.9 and 72.5±3.6%, respectively. The correlation coefficients between serum and serum ultrafiltrate and serum and saliva were 0.926 and 0.654, respectively. These data suggest that MARKIT is a reliable method for the determination of the concentration of antiepileptic drugs in serum, serum ultrafiltrate and saliva.

Competitive Blinding Enzyme-lmmunoassay に基づくヒト血清Phenobarbitalの定量法

Competitive Blinding Enzyme-lmmunoassay に基づくヒト血清Phenobarbitalの定量法