Chimeric Protein Switch Biosensors.

Rapid detection of protein and small-molecule analytes is a valuable technique across multiple disciplines, but most in vitro testing of biological or environmental samples requires long, laborious processes and trained personnel in laboratory settings, leading to long wait times for results and high expenses. Fusion of recognition with reporter elements has been introduced to detection methods such as enzyme-linked immunoassays (ELISA), with enzyme-conjugated secondary antibodies removing one of the many incubation and wash steps. Chimeric protein switch biosensors go further and provide a platform for homogenous mix-and-read assays where long wash and incubation steps are eradicated from the process. Chimeric protein switch biosensors consist of an enzyme switch (the reporter) coupled to a recognition element, where binding of the analyte results in switching the activity of the reporter enzyme on or off. Several chimeric protein switch biosensors have successfully been developed for analytes ranging from small molecule drugs to large protein biomarkers. There are two main formats of chimeric protein switch biosensor developed, one-component and multi-component, and these formats exhibit unique advantages and disadvantages. Genetically fusing a recognition protein to the enzyme switch has many advantages in the production and performance of the biosensor. A range of immune and synthetic binding proteins have been developed as alternatives to antibodies, including antibody mimetics or antibody fragments. These are mainly small, easily manipulated proteins and can be genetically fused to a reporter for recombinant expression or manipulated to allow chemical fusion. Here, aspects of chimeric protein switch biosensors will be reviewed with a comparison of different classes of recognition elements and switching mechanisms.

Enzyme - Switch sensors for therapeutic drug monitoring of immunotherapies.

Therapeutic monoclonal antibodies (TmAb) have emerged as effective treatments for a number of cancers and autoimmune diseases. However, large interpatient disparities in the pharmacokinetics of TmAb treatment requires close therapeutic drug monitoring (TDM) to optimise dosage for individual patients. Here we demonstrate an approach for achieving rapid, sensitive quantification of two monoclonal antibody therapies using a previously described enzyme switch sensor platform. The enzyme switch sensor consists of a ß-lactamase - ß-lactamase inhibitor protein (BLA-BLIP) complex with two anti-idiotype binding proteins (Affimer proteins) as recognition elements. The BLA-BLIP sensor was engineered to detect two TmAbs (trastuzumab and ipilimumab) by developing constructs incorporating novel synthetic binding reagents to each of these mAbs. Trastuzumab and ipilimumab were successfully monitored with sub nM sensitivity in up to 1% serum, thus covering the relevant therapeutic range. Despite the modular design, the BLA-BLIP sensor was unsuccessful in detecting two further TmAbs (rituximab and adalimumab), an explanation for which was explored. In conclusion, the BLA-BLIP sensors provide a rapid biosensor for TDM of trastuzumab and ipilimumab with the potential to improve therapy. The sensitivity of this platform alongside its rapid action would be suitable for bedside monitoring in a point-of-care (PoC) setting.

The effectiveness of interventions that support penicillin allergy assessment and delabeling of adult and pediatric patients by nonallergy specialists: a systematic review and meta-analysis.

OBJECTIVES: Penicillin allergy records are often incorrect and may result in harm. We aimed to systematically review the effectiveness and safety of nonallergist health care worker delivery of penicillin allergy delabeling. METHODS: We searched EMBASE/MEDLINE/CINAHL (Ovid), PsycInfo, Web of Science, and Cochrane CENTRAL from inception to January 21, 2022 and unpublished studies and gray literature. The proportion of patients allergic to penicillin delabeled and harmed was calculated using random-effects models. RESULTS: Overall, 5019 patients were delabeled. Using allergy history alone, 14% (95% confidence interval [CI], 9-21%) of 4350 assessed patients were delabeled without reported harm. Direct drug provocation testing resulted in delabeling in 27% (95% CI, 18-37%) of 4207 assessed patients. Of the 1373 patients tested, 98% were delabeled (95% CI, 97-99%), and nonserious harm was reported in 1% (95% CI, 0-2%). Using skin testing, followed by drug provocation testing, 41% (95% CI, 24-59%) of 2890 assessed patients were delabeled. Of the 1294 tested patients, 95.0% (95% CI, 90-99%) were delabeled, and the reported harm was low (0%; (95% CI 0-1%). CONCLUSION: Penicillin allergy delabeling by nonallergists is efficacious and safe. The proportion of assessed patients who can be delabeled increases with the complexity of testing method, but substantial numbers can be delabeled without skin testing.

Effectiveness of interventions that support penicillin allergy assessment and de-labeling of patients by non-allergy specialists: a systematic review protocol.

OBJECTIVE: This review will systematically examine and synthesize the evidence evaluating the effectiveness and safety of interventions that enable non-allergy specialist health care workers to assess allergy risk in patients with reported penicillin allergies and subsequently remove erroneous allergy records. INTRODUCTION: The potential benefits of removing erroneous penicillin allergy labels (de-labeling) are wide-ranging. Penicillin allergy assessment and de-labeling is an antibiotic stewardship priority. Delivery of such assessment and de-labeling by non-allergy specialists has been reported in several studies, but the effectiveness and safety have not been formally synthesized. This is a necessary step in the upscaling of penicillin allergy assessment services. INCLUSION CRITERIA: This review will consider quantitative studies using appropriate designs. The studies will include adults and pediatric patients who have undergone penicillin allergy assessment and de-labeling by non-allergy specialists in any health care setting. METHODS: A range of databases will be searched to identify studies published in English, with no date limit applied. Unpublished studies and gray literature will also be searched. Title and abstract screening, and assessment of selected full texts against the inclusion criteria will be conducted by at least two independent reviewers. Identified studies will be assessed for methodological quality using standardized critical appraisal instruments. Data will be extracted and categorized using the EPOC taxonomy, and the effectiveness and safety of the intervention will be determined. Where possible, data will be pooled to facilitate meta-analysis. Data from heterogeneous studies will be reported narratively. The GRADE approach for grading the certainty of evidence will be followed. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42020219044.