Evaluation of the feasibility and efficacy of point-of-care antibody tests for biomarker guided management of COVID-19.

BACKGROUND: Biomarker guided therapy could improve management of COVID-19 inpatients. Although some results indicate that antibody tests are prognostic, little is known about patient management using point-of-care (POC) antibody tests. METHODS: COVID-19 inpatients were recruited to evaluate 2 POC tests: LumiraDX and RightSign. Ease of use data was collected. Blood was also collected for centralized testing using established antibody assays (GenScript cPass). A nested case-control study assessed if POC tests conducted on stored specimens were predictive of time to sustained recovery, mortality, and a composite safety outcome. RESULTS: While both POC tests exhibited moderate agreement with the GenScript assay (both agreeing with 89% of antibody determinations), they were significantly different from the GenScript assay. Treating the GenScript assay as the gold standard, the LumiraDX assay had 99.5% sensitivity and 58.1% specificity while the RightSign assay had 89.5% sensitivity and 84.0% specificity. The LumiraDX assay frequently gave indeterminant results. Both tests were significantly associated with clinical outcomes. CONCLUSIONS: Although both POC tests deviated moderately from the GenScript assay, they predicted outcomes of interest. The RightSign test was easier to use and was more likely to detect those lacking antibody compared to the LumiraDX test treating GenScript as the gold standard.

Screening and isolation of quorum sensing inhibitors of Pseudomonas aeruginosa from Phellodendron amurense extracts using bio-affinity chromatography.

Drug-resistant bacterial infections pose a significant challenge in the field of bacterial disease treatment. Finding new antibacterial pathways and targets to combat drug-resistant bacteria is crucial. The bacterial quorum sensing (QS) system regulates the expression of bacterial virulence factors. Inhibiting bacterial QS and reducing bacterial virulence can achieve antibacterial therapeutic effects, making QS inhibition an effective strategy to control bacterial pathogenicity. This article mainly focused on the PqsA protein in the QS system of Pseudomonas aeruginosa. An affinity chromatography medium was developed using the SpyTag/SpyCatcher heteropeptide bond system. Berberine, which can interact with the PqsA target, was screened from Phellodendron amurense by affinity chromatography. We characterized its structure, verified its inhibitory activity on P. aeruginosa, and preliminarily analyzed its mechanism using molecular docking technology. This method can also be widely applied to the immobilization of various protein targets and the effective screening of active substances.

Precision engineering of antibodies: A review of modification and design in the Fab region.

The binding of functional groups to antibodies is crucial for disease treatment, diagnosis, and basic scientific research. Traditionally, antibody modifications have focused on the Fc region to maintain antigen-antibody binding activity. However, such modifications may impact critical antibody functions, including immune cell surface receptor activation, cytokine release, and other immune responses. In recent years, modifications targeting the antigen-binding fragment (Fab) region have garnered increasing attention. Precise modifications of the Fab region not only maximize the retention of antigen-antibody binding capacity but also enhance numerous physicochemical properties of antibodies. This paper reviews the chemical, biological, biochemical, and computer-assisted methods for modifying the Fab region of antibodies, discussing their advantages, limitations, recent advances, and future trends.

Isolation of antibody by polymer microspheres embedded with E. coli displaying IgG-binding domain.

Antibody purification is an important aspect of quality and cost control in the production process of antibody drugs. In this study, modified E. coli was embedded into polymer microspheres (polyvinyl alcohol/alginate) for antibody separation and the IgG binding domain was displayed on the surface of E. coli. The results showed that ZZ protein (Fc binding domain of the antibody) was successfully displayed on the surface of E. coli and was embedded in polyvinyl alcohol/alginate microspheres. In addition, it has excellent specific adsorption capacity for antibodies, with a maximum adsorption capacity of 35.74 mg/g (wet microspheres). Through the adsorption isotherm and adsorption kinetics simulation, the adsorption of IgG on the microsphere matrix conforms to the Langmuir model and follows the pseudo-first-order kinetic equation. The microsphere matrix can undergo saturation adsorption at pH 7.2 and desorption at around pH 3.0. Desorption characteristics are consistent with those of rProtein A Sepharose FF®. After five cycles of the adsorption-desorption processes, the IgG adsorption capacity remains above 80%. Using polymer microspheres to separate antibodies from mouse ascites, the antibody purity reached 86.7% and the yield was 83.5%. These results provide an alternative to protein A matrix with low-cost, fast preparation and moderate efficiency.