Application of germline antibody features to vaccine development, antibody discovery, antibody optimization and disease diagnosis.

Although the efficacy and commercial success of vaccines and therapeutic antibodies have been tremendous, designing and discovering new drug candidates remains a labor-, time- and cost-intensive endeavor with high risks. The main challenges of vaccine development are inducing a strong immune response in broad populations and providing effective prevention against a group of highly variable pathogens. Meanwhile, antibody discovery faces several great obstacles, especially the blindness in antibody screening and the unpredictability of the developability and druggability of antibody drugs. These challenges are largely due to poorly understanding of germline antibodies and the antibody responses to pathogen invasions. Thanks to the recent developments in high-throughput sequencing and structural biology, we have gained insight into the germline immunoglobulin (Ig) genes and germline antibodies and then the germline antibody features associated with antigens and disease manifestation. In this review, we firstly outline the broad associations between germline antibodies and antigens. Moreover, we comprehensively review the recent applications of antigen-specific germline antibody features, physicochemical properties-associated germline antibody features, and disease manifestation-associated germline antibody features on vaccine development, antibody discovery, antibody optimization, and disease diagnosis. Lastly, we discuss the bottlenecks and perspectives of current and potential applications of germline antibody features in the biotechnology field.

A Robust Homogeneous Fluorescence Polarization Immunoassay for Rapid Determination of Erythromycin in Milk.

Erythromycin (ERY) is one of the most common macrolides applied in veterinary medicine to treat diseases or as a feed additive for animal growth promotion. Long-term irrational use of ERY could lead to residues in animal-derived food and the emergence of drug-resistant strains, posing potential threats to human health. In this study, a highly sensitive, specific, robust, and rapid fluorescence polarization immunoassay (FPIA) for the determination of ERY in milk has been described. Herein, to achieve high sensitivity, five tracers of ERY with different fluorescein structures were synthesized and paired with three monoclonal antibodies (mAbs). Under the optimized conditions, the combination of mAb 5B2 and tracer ERM-FITC achieved the lowest IC50 value in the FPIA with 7.39 µg/L for ERM. The established FPIA was used to detect ERY in milk, revealing a limit of detection (LOD) of 14.08 µg/L with recoveries of 96.08-107.77% and coefficients of variations (CVs) of 3.41-10.97%. The total detection time of the developed FPIA was less than 5 min from the addition of samples to the result readout. All the above results showed that the proposed FPIA in this study was a rapid, accurate, and simple method for the screening of ERY in milk samples.

Dual-Wavelength Fluorescence Polarization Immunoassay for Simultaneous Detection of Sulfonamides and Antibacterial Synergists in Milk.

Combinations of sulfonamides (SAs) and antibacterial synergists (ASGs) are frequently used for treating infectious diseases and promoting growth for animals, which cause potential hazards to food safety and human health. To realize the simultaneous detection of SAs and ASGs in food, a homogeneous and high-throughput screening dual-wavelength fluorescence polarization immunoassay (DWFPIA) was developed. In this study, three SAs tracers and three ASGs tracers were synthesized by fluoresceins with different linkers and paired with their corresponding monoclonal antibodies (mAbs), respectively. To achieve a high sensitivity and broad specificity, the combination of tracers SADMPM-HDF with the longest linker paring mAb 10E6 for SAs and tracer HaptenA-DSCA paring mAb 9C9 for ASGs were chosen for the development of DWFPIA, achieving surprising IC50 values for 23 SAs below 100 µg L-1 and 5 ASGs below 50 µg L-1. The accuracy of DWFPIA was applied in real milk samples by typical sulfamethazine (SMZ) and trimethoprim (TMP), with recoveries of 81.7-97.2% and 78.6-103.6%, and coefficient of variations (CVs) below 18.9%, which could be completed within 15 min, including sample pretreatment. We firstly developed a simultaneous screening DWFPIA, covering all of the SAs and ASGs used in clinic and providing a great application potential in food safety analysis.

Comparison of two fluorescence quantitative immunochromatographic assays for the detection of amantadine in chicken muscle.

The two sensitive fluorescence quantitative immunochromatographic assays (FQICAs), background fluorescence quenching immunochromatographic assay (bFQICA) and time-resolved fluorescent immunochromatographic assay (TRFICA), play an important role increasingly in rapid detection technology for food safety. Amantadine (AMD), used extensively in virus infections in livestock and poultry, has been prohibited due to hazard concerns over public human health. Therefore, AMD was used as a model molecule in the FQICAs establishment and comparison based on the same bioreagents. The outstanding performance in technical parameters of the two FQICAs indicated that they could provide rapid, precise, reliable technical support for large-scale on-site screening for AMD detection. What's more, the systematic and comprehensive comparison of the two FQICAs would give useful suggestions for scientists and users in monitoring the harmful compounds.