scholarly journals Characterization of degradation process of sucrase-isomaltase in rat jejunum with monoclonal-antibody-based enzyme-linked immunosorbent assay

1988 ◽  
Vol 250 (1) ◽  
pp. 41-46 ◽  
Author(s):  
T Goda ◽  
A Quaroni ◽  
O Koldovský

As shown previously, during degradation of sucrase-isomaltase in rat jejunum, degradation of the sucrase active site occurs before that of isomaltase active site [Goda & Koldovský (1985) Biochem. J. 229, 751-758]. To characterize further the process of sucrase-isomaltase degradation in jejunum, we determined the amounts of immunoreactive sucrase-isomaltase in rat jejunum by using a monoclonal-antibody-based enzyme-linked immunosorbent assay. By employing two alternative monoclonal antibodies (one reacting with the sucrase subunit and the other reacting with the isomaltase subunit), the amount of antigen-containing sucrase subunit and the amount of antigen-containing isomaltase subunit were separately quantified. In both upper and lower jejunum of rats, the amount of antigen-containing isomaltase subunit was always higher than the amount of antigen-containing sucrase subunit. This difference was attributable mainly to a degradation product of sucrase-isomaltase, which was identified as isomaltase monomer. Occlusion of pancreatic ducts for 18 h eliminated the difference between the amount of antigen-containing sucrase subunit and the amount of antigen-containing isomaltase subunit in both upper and lower jejunum. In jejunum of control animals, the molar ratio of sucrase subunit to isomaltase subunit was estimated to be 0.32-0.52, indicating that quite a large proportion of sucrase-isomaltase (48-68%) is present as degradation products (e.g. isomaltase monomer). These results support the model of degradation process of sucrase-isomaltase in brush-border membranes of rat jejunum, whereby degradation of sucrase subunit by the action of pancreatic proteinase(s) precedes degradation of isomaltase subunit.

Blood ◽  
1987 ◽  
Vol 69 (1) ◽  
pp. 284-289 ◽  
Author(s):  
P Holvoet ◽  
J Boes ◽  
D Collen

Abstract An enzyme-linked immunosorbent assay for free tissue-type plasminogen activator (t-PA) in human blood was developed based on a murine monoclonal antibody directed against the active site of t-PA. The lower limit of sensitivity of the assay applied to plasma is 2 ng/mL for one- chain t-PA but only 100 ng/mL for two-chain t-PA. Free t-PA in plasma taken at rest was found in 6 of 21 healthy subjects (4.5 +/- 0.8 ng/mL, mean +/- SD) and increased to 14 +/- 7.0 ng/mL after venous occlusion in 18 of these individuals. A linear correlation between total t-PA and free t-PA was observed with r = 0.92 (n = 18) and a slope of 1.08, indicating that t-PA released from the vessel wall circulates in the blood as the one-chain form. In 16 of 18 patients with deep vein thrombosis, the increase of total t-PA antigen after venous occlusion was comparable to that observed in controls, but the free t-PA was significantly lower or undetectable. The present assay for free t-PA may be useful for the investigation of the release and inhibition of t- PA under physiological, pharmacological, or pathological conditions in humans.


Blood ◽  
1987 ◽  
Vol 69 (1) ◽  
pp. 284-289
Author(s):  
P Holvoet ◽  
J Boes ◽  
D Collen

An enzyme-linked immunosorbent assay for free tissue-type plasminogen activator (t-PA) in human blood was developed based on a murine monoclonal antibody directed against the active site of t-PA. The lower limit of sensitivity of the assay applied to plasma is 2 ng/mL for one- chain t-PA but only 100 ng/mL for two-chain t-PA. Free t-PA in plasma taken at rest was found in 6 of 21 healthy subjects (4.5 +/- 0.8 ng/mL, mean +/- SD) and increased to 14 +/- 7.0 ng/mL after venous occlusion in 18 of these individuals. A linear correlation between total t-PA and free t-PA was observed with r = 0.92 (n = 18) and a slope of 1.08, indicating that t-PA released from the vessel wall circulates in the blood as the one-chain form. In 16 of 18 patients with deep vein thrombosis, the increase of total t-PA antigen after venous occlusion was comparable to that observed in controls, but the free t-PA was significantly lower or undetectable. The present assay for free t-PA may be useful for the investigation of the release and inhibition of t- PA under physiological, pharmacological, or pathological conditions in humans.


2006 ◽  
Vol 13 (3) ◽  
pp. 420-422 ◽  
Author(s):  
S. E. Burastero ◽  
C. Paolucci ◽  
D. Breda ◽  
G. Monasterolo ◽  
R. E. Rossi ◽  
...  

ABSTRACT The Bühlmann CAST 2000 enzyme-linked immunosorbent assay is a potentially useful assay for measuring sulfidoleukotrienes released in vitro by allergen-challenged basophils. However, we observed that the positive-control reagent yielded positive signals in cell-free systems. These false-positive results depended on using a mouse anti-FcεRI monoclonal antibody and were prevented by degranulation-inducing reagents other than mouse monoclonal antibodies.


2010 ◽  
Vol 120 (4) ◽  
pp. 1178-1184 ◽  
Author(s):  
Yuanyuan Xia ◽  
Qing X. Li ◽  
Shuangjun Gong ◽  
Yong Li ◽  
Yongsong Cao ◽  
...  

1987 ◽  
Vol 82 (1) ◽  
pp. 81-85 ◽  
Author(s):  
Mauro Schechter

Theoretically, serological assays with affinity purified marker antigens can allow strain-specific diagnosis even when parasites cannot be retrieved from and infected host. A Trypanosoma cruzi antigen was purified by affinity chromatography using a zymodeme (Z) 2 specific monoclonal antibody (2E2C11). An indirect enzyme-linked immunosorbent assay (ELISA) based on the purified antigen could discriminate between sera from rabbits immunized with T. cruzi zymodeme clones but could not discriminate between sera from mice infected with different zymodemes.


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