Establishment of a bead-based duplex assay for the simultaneous quantitative detection of Neuropilin-1 and Neuropilin-2 using xMAP technology and its clinical application.

BACKGROUND: Neuropilins (Nrps) are a new type of broad-spectrum tumor marker. Currently, a method for accurate simultaneous quantification of Nrps is not available. We aimed to develop a bead-based and duplexed flow cytometric assay that could be used for accurate and simultaneous quantification of Nrp1 and Nrp2 for scientific research or clinical diagnosis. METHODS: We coupled anti-human Nrp1-11# mAb and anti-human Nrp2-C3 mAb to magnetic beads 18# and 25#, respectively. Capturing antibodies and detecting antibodies were then combined to detect Nrps by a bead-based Luminex assay, which was subsequently applied to quantify Nrps in clinical serum samples. RESULTS: The results showed that the detection value of Nrps ranged from 10 to 100 000 pg/mL for Nrp1 and from 25 to 100 000 pg/mL for Nrp2. The detection sensitivity reached 10 pg/mL for Nrp1 and 24.8 pg/mL for Nrp2. Intra-assay variances ranged from 1.0% to 2.6% for Nrp1 and from 2.9% to 4.0% for Nrp2, and interassay variances ranged from 1.5% to 6.4% for Nrp1 and from 4.2% to 8.1% for Nrp2. The Nrp1 and Nrp2 recoveries were 96.6%-103.6% and 95.6%-102.3%, respectively. Irrelevant antigens had no interference in the paired-detection system, and the mean fluorescence intensity (MFI) values were stable for months. CONCLUSION: A bead-based, duplexed flow cytometric assay (xMAP® technology) was developed to detect Nrp1 and Nrp2. The assay provided rapid, high-throughput results and was much more sensitive, specific, reproducible, and stable than existing assays. In addition, this assay could be applied in early-stage cancer screening, tumor malignancy analysis, and prognosis assessment.

Preparation, Purification, and Identification of a Monoclonal Antibody Against the C-Terminal Domain of Semaphorin3F.

Class three semaphorins were originally identified as mediators of axon guidance, which repelled axons and collapsed growth cones. As a member of class three semaphorins, semaphorin3F (Sema3F) has been found to have similar effects on tumor cells and endothelial cells and also is implicated in the signaling of tumor metastasis by forming a complex with neuropilins and plexins. In this study, our laboratory produced a monoclonal antibody against the C-terminal domain of Sema3F (Sema3Fc mAb) using the hybridoma method, expecting to explore the potential role of the antibody and its application in the detection of Sema3F. The capture enzyme-linked immunosorbent assay (ELISA) method indicated that mAb belonged to the IgM subclass and purified Sema3Fc mAb had a titer of 5.12 × 105 against Sema3Fc by indirect ELISA. In addition, results showed that the Sema3Fc mAb could be applied in such experiments as Western blotting, flow cytometry, immunofluorescence, and immunocytochemical staining. It indicates the Sema3Fc mAb is available in the detection of Sema3F with specificity and will help further study the role and mechanism of Sema3F among tumor cells.

[An analysis of the relationship between HBV DNA and HBeAg expression and mortality in 799 severe hepatitis patients].

OBJECTIVE: To evaluate the relationship between mortality and HBVDNA and HBeAg expression of severe hepatitis B patients. METHODS: The mortality rates of different types of severe hepatitis patients in our hospital during the last five years were analysed. HBV DNA was detected using the fluorescence quantitative PCR method and the HBeAg expression of severe hepatitis B was studied using a microparticle method. RESULTS: (1) Hepatitis B morbidity was 83.5% in each type of severe hepatitis, and severe chronic hepatitis B morbidity was 96.77% in each type of severe chronic hepatitis. (2) The mortality rate of those with HBV DNA more than 1 x 10(5) copies/ml was 53.25% and the mortality of those with HBV DNA less than 1 x 10(5) copies/ml was 34.50% (P less than 0.01). The HBeAg expression had no influence on the death rate. (3) The death rate descended to 30.38% from 54.64% (HBV DNA more than 1 x 10(5) copies/ml) when treated with Lamivudine (P less than 0.01). CONCLUSION: In severe hepatitis the quantity of virus carried in the patient is one of the key factors of mortality; antivirus treatment can lower mortality.