Production and characterization of isotype-specific monoclonal antibodies to bovine brain Rab GDI

Production and Characterization of Monoclonal Antibodies Against Primo Vascular System of Rat

BACKGROUND

The primo vascular system (PVS) has been difficult to detect due to its small diameter and translucent features of the threadlike network. Thus, contrast-enhancing dyes including Alcian blue, Trypan blue and Janus green B had to be used for finding and taking out PVS from rat and mouse.

OBJECTIVE

Generation of monoclonal antibodies (mAbs) against PVS of rat was intended to use as a detector for PVS and a biological tool for functional study of PVS.

MATERIALS AND METHODS

Primo vessel (PV) and Primo node (PN) were isolated from organ surfaces of rat and then their proteins were isolated and injected into mouse as an immunogen. The classical traditional method was applied for production of mAbs against PVS. The various techniques, such as cell fusion, screening of hybridoma, ELISA, Western blotting (WB), immunofluorescence microscopy (IF), and limiting dilution, were used to generate mAbs against PVS.

RESULTS

Among 16 mAbs generated, 4 representative mAbs were characterized with their specificities in ELISA, WB, and IF. α-rPVS-m1-1 and α-rPVS-m4-6 had strong binding affinities to PVS in both ELISA and WB but did not show specificities in IF at all. On the contrary, α-rPVS-m3-2 and α-rPVS-m3-4 almost did not respond in WB but had strong binding affinities in ELISA and specificities in IF. Two mAbs stained predominantly at extra cellular matrix and cell membrane of PVS of rat in IF, and they were able to discriminate PVS from blood vessel (BV) and lymphatic vessel (LV).

CONCLUSIONS

4 representative mAbs against PVS of rat were characterized by ELISA, WB, and IF. α-rPVS-m3-2 and α-rPVS-m3-4, which had strong specificities in IF, can be used as a tool in discriminating PVS from other similar tissues and in elucidate biological function of PVS.

Common Salivary Protein 1 in Serum of Diabetes Patients

BACKGROUND

Recently, the human common salivary protein 1 (CSP1) was identified as an ortholog of the Demilune cell and parotid protein of mouse. However, its function remains to be determined. Here, we show that the serum CSP1 concentration of diabetes mellitus (DM) patients is much higher than that of healthy controls.

METHODS

Recombinant human CSP1 was expressed as a Glutathione-S-transferase (GST)-tagged protein, and the purified fusion protein was used as an immunogen to generate monoclonal antibody (mAb) to CSP1. The produced mAb was tested as a probe in Western blotting of human saliva and in immunohistochemistry of various human tissues. The serum CSP1 levels of 31 DM patients and 38 normal adults were quantified by a house-fabricated CSP1 sandwich enzyme-linked immunosorbent assay (ELISA) system.

RESULTS

Immunoblot analysis by mAb-hCSP1#4 showed that CSP1 in human saliva exists in a 27 kDa glycosylated form. Among the various human tissues tested, the salivary gland was the only tissue stained with mAb-hCSP1#4 by immunohistochemistry. Quantification of serum CSP1 concentration by CSP1 ELISA showed that the median values (25th-75th percentile) of DM patients and healthy adults were 22.2 (15.8-28.2) and 3.2 (0-11.4), respectively. Student's t-test results indicated that there was a statistically significant difference between the two groups (P < 0.01).

CONCLUSION

The significant difference between the CSP1 levels of the two groups indicated that CSP1 would be a potential biomarker for detection or screening of DM patients.

Rapid Analytical Detection of Microcystins Using Gold Colloidal Immunochromatographic Strip

Routine monitoring of microcystin in natural waters is difficult because the concentration of the toxin is low and the detection method is usually complicated. We developed a rapid analytical detection method of microcystins gold colloidal immunochromatogeraphic strip. The sensitivity of the strip is about 1 ng/mL for microcystin LR; it is able to distinguish visually among different concentrations of microcystin solutions. The developed gold colloidal strip can detect microcystins within 15 min and does not require either a complicated extraction system, or trained or qualified experts.

Enzyme-linked immunosorbent assay detection of microcystins using new monoclonal antibodies

New monoclonal antibodies (mAbs) against the microcystin-leucine-arginine variant (microcystin-LR), a cyclic peptide toxin of the freshwater cyanobacterium Microcystis aeruginosa, were prepared from cloned hybridoma cell lines. Using these mAbs, an enzyme-linked immunosorbent assay (ELISA) experiment was made for the detection of cyanobacterial hepatotoxins, microcystins in water sampled in Soyang Lake, Korea. The performance of the ELISA test with mAbs established in this study was evaluated. The ELISA detection was compared with HPLC detection. Since the detection limit of HPLC is several orders of magnitude higher than with ELISA, attention was also paid to concentration of samples with solid phase extraction cartridges.

A rapid, simple measurement of human albumin in whole blood using a fluorescence immunoassay (I)

BACKGROUND

Human serum albumin (HSA) is the most abundant plasma protein and plays key a role in metabolism. The variation in albumin concentration provides valuable information related to metabolic diseases and diagnostic application.

METHODS

We constructed two assay systems to quantify the albumin concentration. The immunoassay used a fluorescence (FL) dye to detect albumin in samples and employed the conventional chromatography as a separation system. The assay system consists of an anti-HSA-mAb or an HSA immobilized test strip in a disposable cartridge, a fluorescence-labeled detector buffer and a laser-fluorescence scanner. We mixed the sample with detector, loaded it onto a cartridge, incubated it for 10 min and measured the concentration of albumin in a laser-fluorescence scanner. We examined the comparability of assay with an automated BCG dye binding method using a Hitachi 747 biochemical analyzer.

RESULTS

The correlation of coefficient between AT/AC as converted from the relative fluorescence units (RFU) and albumin concentration displayed reasonable reliability in both the competition and the inhibition assay systems (r = 0.998). Using the Bland-Altman difference plot analysis, we observed an acceptable agreement between two methods, the fluorescence immunochromatography assay (FL-ICA) and the automated BCG dye-binding method of a Hitachi biochemical analyzer, over the clinical relevant range of HSA concentrations. The coefficient of variation (CV) of within- and between-run variation in the immunoassay system was < 8% and the recovery fell within 5% in each control sample. In addition to its reliable analytical performance, the assay with whole blood can be completed in 12 min using a one-step operation without any pretreatment.

CONCLUSION

The developed immunoassay system using fluorescence dye and lateral-flow chromatography is a simple, fast and reliable method for quantifying the albumin concentration in whole blood.

Development of an electrochemical immunosensor for alanine aminotransferase

Alanine aminotransferase (ALT) has been regarded as one of the most sensitive indicators of hepatocellular damage. While ALT is widely used in the practice of medicine, few attempts have been made to develop biosensors applicable to the on-site diagnosis of liver diseases. In the hope of developing an immunosensor for measurement of ALT activity, we have generated monoclonal antibodies to human recombinant ALT and fabricated them for use in a sensor. The ALT immunosensor was composed of the followings: (1) anti-ALT antibody-immobilized outer membrane; (2) pyruvate oxidase-absorbed inner membrane; (3) a self assembled monolayer mediator-coated gold working electrode and an Ag/AgCl reference electrode. The chronoamperometric measurement of the immunosensor was performed with 40 microl of PBS containing substrates and ALT without a washing step in less than 5 min. The dynamic range of ALT immunosensor was presented as five orders of magnitude, ranging between 10 pg/ml and 1 microg/ml. The detection limit and the sensitivity were 10 pg/ml and 26.3 nA/(ng/ml), respectively. In the meantime, the enzyme sensor fabricated without anti-ALT antibody showed much poorer analytical values. The dynamic range, the detection limit, and the sensitivity were 10 ng/ml-100 microg/ml, 10 ng/ml and 11.4 nA/(ng/ml), respectively. The presented results indicated that the immunosensor system provided much better technical performance in all of the aspects evaluated than did the enzyme sensor without the immobilized-antibody.

Development of a point-of-care assay system for high-sensitivity C-reactive protein in whole blood

BACKGROUND

C-reactive protein (CRP) is emerging as a potential risk predictor for future cardiovascular diseases (CVD). High sensitivity assays have been developed and applied for clinical purposes.

METHODS

The fluorescence immunochromatographic assay was employed to detect and quantify CRP in whole blood. It consisted of a fluorescence (FL) antibody detector buffer, a test strip housed in a disposable cartridge, and a laser fluorescence scanner. Whole blood sample was mixed with detector, loaded onto a cartridge, incubated for 10 min, and the concentration of CRP was measured in a laser fluorescence scanner. The linearity, limit of detection (LOD), and performance of new assay system was tested and evaluated. The comparability of assay was examined with an automated reference method.

RESULTS

With the new assay system, a reliable correlation of coefficient (r) was obtained between the ratio value (A(T)/A(C)) and a concentration of CRP in samples. The linearity fell in the range of 0-10 mg/l of CRP, and the analytical detection limit was 0.133 mg/l of CRP. The mean recovery of the control was 105.2% in a working range. The precision of the intra- and inter-assay in a range of 0.5-6 mg/l was CVs <6% and <8%, respectively. The new fluorescence immunochromatographic assay system correlated well with a traditional immunoturbidimetric assay for quantification of CRP concentration (r=0.955, N=90).

CONCLUSION

The fluorescence immunochromatographic assay is fast, reliable, and a reproducible platform for point-of-care testing (POCT) of high-sensitive (hs)-CRP in whole blood.