Monoclonal antibodies directed against the outer membrane protein of Bordetella avium

Development of ELISA and Lateral Flow Immunoassays for Ochratoxins (OTA and OTB) Detection Based on Monoclonal Antibody

Ochratoxins were important secondary metabolites secreted by fungi, and OTA and OTB are mainly significant mycotoxin, having toxic effects on humans and animals. Therefore, it is important to establish a rapid, sensitive, and precise method for ochratoxins detection and quantification in real samples. In this study, a stable monoclonal antibody (mAb) that recognizing both OTA and OTB toxins was employed for the establishment of indirect competitive ELISA (ic-ELISA), colloidal gold nanoparticles (CGNs), and nanoflowers gold strips (AuNFs) for detection of ochratoxins in real samples. A 6E5 hybridoma cell line stable secreting mAb against both OTA and OTB toxins was obtained by fusion of splenocytes with myeloma SP2/0 cells. The 6E5 mAb had a high affinity (3.7 × 10⁸ L/mol) to OTA, and also showed similar binding activity to OTB. The optimized ic-ELISA resulted in a linear range of 0.06–0.6 ng/mL for ochratoxins (OTA and OTB) detection. The IC50 was 0.2 ng/mL and the limit of detection (LOD) was 0.03 ng/mL. The mean recovery rate from the spiked samples was 89.315 ± 2.257%, with a coefficient variation of 2.182%. The result from lateral flow immunoassays indicated that the LOD of CGNs and AuNFs were 5 and 1 μg/mL, respectively. All these results indicated that the developed ic-ELISA, CGNs, and AuNFs in this study could be used for the analysis of the residual of ochratoxins (OTA and OTB) in food and agricultural products.

The Preparation and Identification of a Monoclonal Antibody against Domoic Acid and Establishment of Detection by Indirect Competitive ELISA

Domoic acid (DA) is a potent toxin, marine biotoxin, and primarily produced by Pseudo-nitzschia. The DA hapten was coupled with bovine serum albumin (BSA), and ovalbumin (OVA) as carrier proteins. DA-BSA conjugate was used as immunogen and DA-OVA as coating antigen. Cell fusion between spleen cells and sp2/0 myeloma cells developed 1C3 hybridoma clone producing 1C3 monoclonal antibody (mAb). Hybridoma was injected into the mice to produce ascites, and further purified by caprylic acid/ammonium sulfate method. The mAb was of IgG3 subclass, and was specific to DA with high affinity (2.5 × 10⁸ L/mol). Moreover, western blot exhibited significant specificity to the DA antigens. Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) showed DA working range of 0.006–0.2 ng/mL. The IC₅₀ was 0.03 ng/mL with low limit of detection (LOD) of 0.006 ng/mL. Average DA recovery from spiked shellfish extract was 100.56 ± 2.8% with the coefficient variation of 0.01–0.1%. Hence, mAb producing 1C3 hybridoma was successfully developed and could be used to detect DA in contaminated samples.

Biosensors of bacterial cells

Biosensors are devices which utilize both an electrical component (transducer) and a biological component to study an environment. They are typically used to examine biological structures, organisms and processes. The field of biosensors has now become so large and varied that the technology can often seem impenetrable. Yet the principles which underlie the technology are uncomplicated, even if the details of the mechanisms are elusive. In this review we confine our analysis to relatively current advancements in biosensors for the detection of whole bacterial cells. This includes biosensors which rely on an added labeled component and biosensors which do not have a labeled component and instead detect the binding event or bound structure on the transducer. Methods to concentrate the bacteria prior to biosensor analysis are also described. The variety of biosensor types and their actual and potential uses are described.

Highly sensitive detection of cancer antigen human epidermal growth factor receptor 2 using novel chicken egg yolk immunoglobulin

Human epidermal growth factor receptor 2 (HER2) is an important biomarker that plays a crucial role in therapeutic decision-making for breast cancer patients. Ensuring the accuracy and reproducibility of HER2 assays by enzyme-linked immunosorbent assay (ELISA), western blot and immunohistochemistry (IHC) requires high sensitive and specific antibodies. Immunoglobulin Y (IgY) is a kind of avian antibody usually isolated from chicken egg yolks. Generation and use of IgY is of increasing interest in a wide variety of applications within the life sciences. In this study, IgY antibodies against two different truncated proteins of the extracellular domain (ECD) of human HER2 were produced, their sensitivity and specificity were evaluated. Specific IgYs were produced by hens immunized with the ECD proteins of human HER2 in long-standing immunization response and were isolated from yolks with a purity of 90% by water dilution, salt precipitations and ultrafiltration. The anti-HER2 IgYs were analytically validated for specificity by ELISA, western blot, immunocytochemistry and IHC. The IgYs bound desired targets in cells and fixed tissues and showed high affinity to HER2. The results demonstrated the viability of detection of HER2 with IgYs and showed promise for the using of IgYs in strict clinical validation.