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Chronic Kidney Disease (CKD) is becoming one of the major causes of morbidity and mortalities in 21st century. We have developed a bioengineered cellulosic paper device for the quantification of albumin (ALB) in physiological samples. The paper surface was activated and antibodies specific to target biomarker was immobilized on engineered paper surface. Every step after modification was characterized by FTIR, XPS, SPM and optical analysis. Further, the device model was designed using CAD file, and a 3-D cascade device was fabricated with in-built constant light source to provide proper and controlled environment for in-situ image analysis. After adding the sample on the bioengineered paper, the antigen-antibody reaction takes place, after that addition of dye results in change of color from yellow to blueish-green within 40 s. An optical method was employed for the analysis of the images by recognizing the specific area and the color intensity. Additionally, the immunosensor specificity was evaluated on number of molecules that are usually found in the serum sample. The linear dynamic range of the developed immunosensor has been reported to be 1–60 mg/mL, covering the normal as well as clinical range of ALB in physiological samples with a detection limit of 0.049(±0.002) mg/mL. With good precision and recovery, the device was able to successfully determine the ALB concentrations in serum sample. The developed device has simple and user-friendly interface and it may also help diagnosing CKD in personalized settings. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) is an extensively used technique to characterize antigen-antibody interactions. Affinity measurements by SPR typically involve testing the binding of antigen in solution to monoclonal antibodies (mAbs) immobilized on a chip and fitting the kinetics data using 1:1 Langmuir binding model to derive rate constants. However, when it is necessary to immobilize antigens instead of the mAbs, a bivalent analyte (1:2) binding model is required for kinetics analysis. This model is lacking in data analysis packages associated with high throughput SPR instruments and the packages containing this model do not explore multiple local minima and parameter identifiability issues that are common in non-linear optimization. Therefore, we developed a method to use a system of ordinary differential equations for analyzing 1:2 binding kinetics data. Salient features of this method include a grid search on parameter initialization and a profile likelihood approach to determine parameter identifiability. Using this method we found a non-identifiable parameter in data set collected under the standard experimental design. A simulation-guided improved experimental design led to reliable estimation of all rate constants. The method and approach developed here for analyzing 1:2 binding kinetics data will be valuable for expeditious therapeutic antibody discovery research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. https://www.elsevier.com/declaration-of-competing-interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Phenanthrene (PHE), as a structurally simple, tricyclic, polycyclic aromatic hydrocarbon (PAHs), is widely present in marine environments and organisms, with serious ecological and health impacts. It is crucial to study fast and simple high-sensitivity detection methods for phenanthrene in seawater for the environment and the human body. In this paper, a immunosensor was prepared by using a multi-wall carbon nanotube (MWCNTs)-chitosan oligosaccharide (COS) nanocomposite membrane loaded with phenanthrene antibody. The principle was based on the antibody–antigen reaction in the immune reaction, using the strong electron transfer ability of multi-walled carbon nanotubes, coupled with chitosan oligosaccharides with an excellent film formation and biocompatibility, to amplify the detection signal. The content of the phenanthrene in seawater was studied via differential pulse voltammetry (DPV) using a potassium ferricyanide system as a redox probe. The antibody concentration, pH value, and probe concentration were optimized. Under the optimal experimental conditions, the response peak current of the phenanthrene was inversely proportional to the concentration of phenanthrene, in the range from 0.5 ng·mL−1 to 80 ng·mL−1, and the detection limit was 0.30 ng·mL−1. The immune sensor was successfully applied to the detection of phenanthrene in marine water, with a recovery rate of 96.1~101.5%, and provided a stable, sensitive, and accurate method for the real-time monitoring of marine environments. [ABSTRACT FROM AUTHOR]

Immunoassays, which use antigen–antibody reactions, are the primary techniques used to selectively quantify specific disease markers in blood. Conventional immunoassays, such as the microplate-based enzyme-linked immunosorbent assay (ELISA) and paper-based immunochromatography, are widely used, but they have advantages and disadvantages in terms of sensitivity and operating time. Therefore, in recent years, microfluidic-chip-based immunoassay devices with high sensitivity, rapidity and simplicity, which are compatible with whole blood assays and multiplex assays, have been actively investigated. In this study, we developed a microfluidic device using gelatin methacryloyl (GelMA) hydrogel to form a wall-like structure in a microfluidic channel and perform immunoassays inside the wall-like structure, which can be used for rapid and highly sensitive multiplex assays with extremely small sample amounts of ~1 μL. The characteristics of GelMA hydrogel, such as swelling rate, optical absorption and fluorescence spectra, and morphology, were carefully studied to adapt the iImmunowall device and immunoassay. Using this device, a quantitative analysis of interleukin-4 (IL-4), a biomarker of chronic inflammatory diseases, was performed and a limit of detection (LOD) of 0.98 ng/mL was achieved with only 1 μL sample and 25 min incubation time. The superior optical transparency over a wide range of wavelengths and lack of autofluorescence will help to expand the application field of the iImmunowall device, such as to a simultaneous multiple assay in a single microfluidic channel, and provide a fast and cost-effective immunoassay method. [ABSTRACT FROM AUTHOR]

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Creatinine and albumin are crucial biomarkers for health monitoring and their ratio in urine is an effective approach for albuminuria assessment. Herein, to address the challenges of point-of-care and efficient analysis of the biomarkers simultaneously, we developed a fully integrated handheld smartphone-based photoelectrochemical biosensing system. A miniaturized printed circuit board included a potentiostat for photocurrent measurements and single-wavelength light-emitting diodes (LEDs) for photo-excitation, which was controlled with a Bluetooth-enabled smartphone. Graphitic carbon nitride (g-C3N4)/chitosan nanocomposites were modified on a transparent indium tin oxide (ITO) electrode as photoactive materials. Creatinine was detected through chelate formation with copper ion probes, while albumin was recognized specifically by an antigen–antibody reaction based on immunoassay. The biosensing system demonstrated good linearity and high sensitivity, with detection ranges of 100 μg mL−1 to 1500 μg mL−1 for creatinine, and 9.9 μg mL−1 to 500 μg mL−1 for albumin. Spiked artificial urine samples with different concentrations were tested to confirm the practical validity of the biosensing system, where an acceptable recovery rate ranged from 98.7% to 105.3%. This portable photoelectrochemical biosensing platform provides a convenient and cost-effective method for biofluid analysis, which has an extensive prospect in point-of-care testing (POCT) for mobile health. [ABSTRACT FROM AUTHOR]

We designed a simple, inexpensive, and user-friendly assay using mesoporous silica nanoparticles to detect analytes. Highly stable and uniform palladium nanoparticles covered with mesoporous silica (Pd@mSiO2) were generated and characterized extensively using physical methods. Human Serum Albumin (HSA) protein or ssDNA specific to the HIV gag region was capped onto the Pd@mSiO2 electrostatically. This "cap" prevented the Pd(0) inside the mesoporous silica nanoparticles from catalyzing the conversion of non-fluorescent molecules to fluorescent molecules. In the presence of target anti-HSA antibodies or complementary sequence (HIV gag), HSA protein or DNA cap dissociated from the surface of Pd@mSiO2-NH2 through the specific antigen–antibody reaction or DNA hybridization, allowing Pd(0) to convert the non-fluorescent molecules to fluorescent molecules. The limit and range of detection of anti-HSA antibodies were 3.8 nM and 3.8 nM to 133.3 nM, respectively. The limit and range of detection of HIV gag were 1.6 nM and 1.6 nM to 15 nM, respectively. This simple, inexpensive, "add sample and measure" diagnostic assay could potentially be incorporated into point of care diagnostics for low-resource settings. [ABSTRACT FROM AUTHOR]

Portable glucose meter (PGM) has played vital roles in the field of medicine, with advantages of accurate and quantitative results, portability, easy operation, and low cost. Recently, more and more researchers have extended the application of PGM in detecting foods contaminations. In this paper, a review of the application of PGM based on target recognition elements, such as antibody–antigen reaction, molecularly imprinted polymer, nucleic acid hybridization, enzyme recognition, and click chemistry, and amplification strategies in food safety and contaminant analysis are described in detail. The future development of the application of glucose meters in food safety supervision is also discussed. [ABSTRACT FROM AUTHOR]

Small extracellular vesicles (sEVs) have attracted wide attention as a promising tumor biomarker. However, sensitive and selective detection of sEVs is challenging due to the low levels of sEVs in the early stage of cancers. Herein, a novel fluorescent sensor was developed for the detection of sEVs with high sensitivity and selectivity based on nonlinear hybridization chain reaction (nHCR) signal amplification and immunomagnetic separation. Firstly, sEVs were captured and enriched by CD63 antibody conjugated magnetic beads via antibody–antigen reactions. Then, cholesterol-modified DNA probes were anchored spontaneously on lipid membranes of sEVs through efficient hydrophobic interactions between the cholesterol moiety and the phospholipid bilayer of sEVs. The simultaneous recognition of the transmembrane protein and the phospholipid bilayer structure of the sEVs could effectively eliminate interferences from free proteins. The sticky ends of the cholesterol-modified DNA probes acted as the initiator to trigger nHCR to form a hyperbranched network of DNA structure that could recruit more fluorescent signal molecules for signal amplification. Under the optimal conditions, the nHCR-based strategy showed high sensitivity for the detection of sEVs with a limit of detection of 80 particles per μL. In addition, the as-constructed method was successfully applied for the analysis of clinical samples. It provides a sensitive and selective platform for the isolation and detection of sEVs in the early diagnosis of cancers. [ABSTRACT FROM AUTHOR]

A quick and easy method to detect the GDF-15 protein (Growth Differentiation Factor-15) has been developed, which utilize the magnetic response of magnetic nanoparticles by switching magnetic fields. The magnetic nanoparticles and GDF-15 are bound by an antigen-antibody reaction and aggregated into a spherical shape using a needle-shaped magnetic yoke. The density of GDF-15 changed as follows: 0, 1 ng/ml, 10 ng/ml, and 100 ng/ml. The increase of GDF-15 aggregated the magnetic nanoparticles and enhanced the signal-to-noise ratio. We also tried the sandwich-type bound method using a primary and secondary antibody with additional magnetic nanoparticles and obtained the enhancement of the magnetic signal in a lower concentration (under 10 ng/ml) of GDF-15. The cross-bridges between magnetic nanoparticle and the protein may strengthen the magnetic couplings of nanoparticles. [ABSTRACT FROM AUTHOR]

This document provides a biography of Gaston Ramon, a prominent figure in the field of immunology. Ramon made significant contributions to humoral immunology between 1922 and 1926, including the development of toxoids and the optimization of the humoral immune response with adjuvants. His work in serotherapy, or passive immunotherapy, involved transferring specific antibodies from an immunized subject to another individual for prophylactic or curative purposes. Ramon's discoveries and techniques greatly advanced the field of immunization and paved the way for the development of effective vaccines. [Extracted from the article]

Pollen-food allergy syndrome (PFAS) is a common IgE-mediated allergic condition resulting from cross-reactions between pollen and plant food allergens, primarily those in the PR-10 subfamily. Mostly symptoms are limited to the mouth and throat causing oral allergy syndrome (OAS). Systemic reactions are extremely rare. We report an 11-year-old boy who experienced a unique anaphylactic reaction after consuming raw carrot juice. The patient exhibited symptoms within one minute, including abdominal pain, facial and eyelid swelling, dyspnea, a macular rash, choking sensation and drowsiness. Desloratadine alleviated these symptoms, and as his overall condition improved rapidly, there was no need for adrenaline administration. Carrot-specific IgE levels in the patient's serum were as follows: Dau c: 40.63 kUA/L and Dau c1: 31.5 kUA/L. He had previously been diagnosed with seasonal allergic rhinoconjunctivitis. The high degree of similarity among allergen components within the PR-10 subfamily contributed to cross-reactivity between birch pollen and carrots. It is important to remember that PFAS can manifest systemically, with symptoms ranging from mild skin itching to potentially fatal consequences. This highlights the need for healthcare professionals to be extra cautious and aware of this possibility, especially since carrots are commonly found in a wide range of dishes and snacks. [ABSTRACT FROM AUTHOR]

Simple Summary: It is debatable whether lymphatic vessels exist in the dental pulp. Most researchers confirm their presence; however, the lymphatic system in the dental pulp is much less developed compared to other tissues of the body. Lymphangiogenesis occurs in the dental pulp with inflammatory changes as a response to inflammatory stimuli acting on the tooth. If lymphangiogenesis is defined as the development of lymphatic vessels from already existing ones, such a mechanism is possible only when lymphatic vessels are present in healthy teeth. Research papers have not conclusively proved whether lymphatic vessels can form in the dental pulp. The use of an immunohistochemical examination can very likely prove the presence of a lymphatic system in dental tissues. However, the evaluation of the lymphatic system of the teeth is problematic because it is quite difficult to clearly distinguish lymphatic vessels from small blood vessels. Despite many studies, opinions on the lymphatic system of the teeth are still incompatible. Studies using light and electron microscopy and directly using methods such as a radioisotope (radionuclide) scan and interstitial fluid pressure measurement reported incomplete results. Immunohistochemistry (IHC) plays the main role in investigating presence of the lymphatic system in dental tissues. This method uses labeled antibodies against antigens typical of lymphatic vessels. The use of appropriate staining enables the detection of antigen-antibody reaction products using a light (optical), electron or fluorescence microscope. However, these studies do not show the system of vessels, their histologic structure under physiological conditions and inflammation as well as the lymphangiogenesis process in the dental pulp. Unfortunately, there is a lack of studies associating the presence of lymphatic vessels in the dental pulp with local lymphatic nodes or large vessels outside the tooth. In the scientific and research environment, the evaluation of the lymphatic system of the teeth is problematic because it is quite difficult to clearly distinguish lymphatic vessels from small blood vessels. Despite many indications of the presence of lymphatic vessels in the pulp chamber, this problem remains open and needs further research. [ABSTRACT FROM AUTHOR]

Today, the home pregnancy test is the most frequently performed laboratory test for self-diagnosis (home diagnostic test). It is also the first laboratory test that has been adapted for self-use at home. This is probably because women have always wanted to know the answer to the question: "Am I pregnant or not?" and always preferred to know the answer to this question intimately and in a discreet way. The history of the pregnancy test is also an interesting example of how the discovery of antibodies and the development of in vitro diagnostic methods based on the antigen–antibody reaction were important for the development of laboratory and clinical diagnostics. Immunodiagnostic techniques (based on the antigen–antibody reaction) are currently the basis of modern specialist laboratory diagnostics, which is essential in clinical diagnosis. The history of the pregnancy test is an interesting one and dates back to ancient times. A pregnancy test is defined as a procedure intended to reveal the presence or absence of pregnancy. Nowadays, every pregnancy test is based on the detection of human chorionic gonadotropin (hCG) in urine or blood. Human chorionic gonadotropin is secreted by the placenta right after a fertilized egg cell implants in the uterus and can be detected in both the urine and blood of pregnant women. Urine pregnancy tests are convenient for self-use at home. Blood tests are performed in medical laboratories. Specialized laboratory methods not only detect hCG but also determine the concentration of this hormone. However, both of these methods are highly accurate and common. Throughout the ages, many different methods were used to detect pregnancy at the earliest stage. Grain, wine, and various small animals were used as research tools. These were both long-term and often unreliable; most were based on folk beliefs and superstitions. Animal pregnancy tests were the first biological tests used in this field. This was a significant advance in the accurate detection of relatively early pregnancy. Animal tests in modern times are considered cruel and inhumane, no matter how reliable their results can be. Their place is now taken by much more specific, more sensitive, and definitely more ethical immunochemical tests. The pregnancy test and the methods to find out whether a woman is pregnant have gone through massive transformations, from bioassays using plants to bioassays on animals to advanced immunochemical techniques and biosensors. Modern pregnancy tests are not invasive and are very sensitive. Nowadays, it takes only about 3 min to know the answer to the question: "Am I pregnant or not?". However, it was not always as simple as it is today. This manuscript aims to show the important role played by antibodies in the development of laboratory and clinical diagnostics in the example of the interesting history of the pregnancy test. [ABSTRACT FROM AUTHOR]

Conventional serum antibody titer, which expresses antibody level, does not provide antigen binding avidity of the variable region of the antibody, which is essential for the defense response to infection. Here, we quantified anti-SARS-CoV-2 antibody binding avidity to the receptor-binding domain (RBD) by competitive binding-inhibition activity (IC50) between SARS-CoV-2 S1 antigen immobilized on the DCP microarray and various RBD doses added to serum and expressed as 1/IC50 nM. The binding avidity analyzed under equilibrium conditions of antigen–antibody binding reaction is different from the avidity index measured with the chaotropic agent, such as urea, under nonequilibrium and short-time conditions. Quantitative determination of the infection-protection potential of antibodies was assessed by ABAT (antigen binding avidity antibody titer), which was calculated by the quantity (level) × quality (binding avidity) of antibodies. The binding avidity correlated strongly (r = 0.811) with cell-based virus-neutralizing activity. Maturation of the protective antibody induced by repeated vaccinations or SARS-CoV-2 infection was classified into three categories of ABAT, such as an initial, low, and high ABAT. Antibody maturity correlated with the clinical severity of COVID-19. Once a mature high binding avidity was achieved, it was maintained for at least 6–8 months regardless of the subsequent change in the antibody levels. [ABSTRACT FROM AUTHOR]

Simple Summary: In situ vaccination (ISV) envisages the intratumoral injection of immunostimulatory molecules, which inflame the tumor and induce anti-tumor immune responses. Since bacterial outer membrane vesicles (OMVs) are naturally decorated with components which stimulate innate immunity, we tested whether OMVs can be used in ISV. Using three different tumor mouse models, we demonstrated the effectiveness of OMVs in inhibiting tumor development and in curing a large fraction of treated mice. We also show that if combined with tumor-specific neoantigens, the anti-tumor activity of OMVs is further enhanced. These latter results are particularly relevant since they support the use of a general strategy to optimize any in situ vaccination protocol. Considering their potency and the ease with which are produced, OMV-based ISV has the potential to become a standard of care for most solid tumors, particularly as a neoadjuvant therapy to be performed before surgery. In situ vaccination (ISV) is a promising cancer immunotherapy strategy that consists of the intratumoral administration of immunostimulatory molecules (adjuvants). The rationale is that tumor antigens are abundant at the tumor site, and therefore, to elicit an effective anti-tumor immune response, all that is needed is an adjuvant, which can turn the immunosuppressive environment into an immunologically active one. Bacterial outer membrane vesicles (OMVs) are potent adjuvants since they contain several microbe-associated molecular patterns (MAMPs) naturally present in the outer membrane and in the periplasmic space of Gram-negative bacteria. Therefore, they appear particularly indicted for ISV. In this work, we first show that the OMVs from E. coli BL21(DE3)Δ60 strain promote a strong anti-tumor activity when intratumorally injected into the tumors of three different mouse models. Tumor inhibition correlates with a rapid infiltration of DCs and NK cells. We also show that the addition of neo-epitopes to OMVs synergizes with the vesicle adjuvanticity, as judged by a two-tumor mouse model. Overall, our data support the use of the OMVs in ISV and indicate that ISV efficacy can benefit from the addition of properly selected tumor-specific neo-antigens. [ABSTRACT FROM AUTHOR]

One possibility is that a chronic and/or latent first pathogen infection can cause conventional T-cell exhaustion for T-cells targeting itself, and also accelerate T-cell exhaustion for T-cells targeting a second pathogen [[1]]. 1 summarizes accelerated T-cell exhaustion outcomes which can cause one of the transient hyperinflammatory diseases or one of the chronic autoimmune diseases or possibly a fatal outcome In conclusion, interactions between two intracellular pathogens can have significant consequences, including accelerated T-cell exhaustion for a second pathogen. This delay time is shorter than the time needed for conventional complete T-cell exhaustion [[1]], and this delay time is plausibly more consistent with a multistep process of accelerated T-cell exhaustion, inducing less-developed antibody production, resulting in extensive antigen-antibody immune complex titers in a phagocytosis impaired host, causing a Type III hypersensitivity immune reaction. [Extracted from the article]

In this study, we prepared ultrasmall FeCo nanoparticles (NPs) with a high magnetic moment and examined their antigen-antibody reaction for biodetection applications. The FeCo NPs were collected from the FeCo-BaF2 nanogranular film with Fe:Co:Ba:F = 14:11:21:54 at.%, by dissolving the film in water since the BaF2 matrix was deliquescent. The size of FeCo NPs was ∼5 nm and the saturation magnetization was estimated to be ∼15.30 kG (149.0 emu/g). The Candida albicans antibodies (abcam ab53891)-conjugated FeCo NPs were collected by using an ultracentrifugal separation (110 000 rpm, 90 min), they were then reacted with Candida albicans. The obtained result indicates that Candida albicans were absorbed successfully onto FeCo NPs, and the number of Candida albicans bound to FeCo NPs counted from the micrographs of the aggregates of FeCo NPs and Candida albicans increased significantly by adding sonication treatment of the film in water before binding them to the antibodies. The success of antigen-antibody reaction of ultrasmall NPs with high magnetic moment improves detection sensitivity as well as offers potential detection for smaller biomolecules. [ABSTRACT FROM AUTHOR]

Changes in the limits of detection (LODs) for a multiplex lateral flow immunoassay (LFIA) caused by different locations of the binding zone on the test strips were studied. Due to the non-equilibrium conditions of the immune reactions in LFIAs, their analytical parameters are susceptible to the binding constants of antigen–antibody reactions and assay duration. Consequently, the integration of several tests into one multiplex assay can cause a significant worsening of the sensitivity. In this study, we propose a simple methodology for the determination of the best arrangement of binding zones, which takes into account the binding constants for immunoreagents. LFIAs of four mycotoxins, namely, aflatoxin B1, deoxynivalenol, T-2 toxin, and ochratoxin A, were integrated into a multiplex test strip. An enzyme-linked immunosorbent assay was applied to determine the equilibrium and kinetic constants of the immunoreactants for each analyte. It was found that the arrangement of binding zones with a descending order of the equilibrium association constants was optimal and provided both lower detection limits and a more uniform coloration. The selected position of the binding zones allowed decreasing the LODs down to 2 and 27 times for ochratoxin A and deoxynivalenol, respectively. The proposed approach can be applied to multiplex LFIAs for different analytes. [ABSTRACT FROM AUTHOR]

An outbreak of the coronavirus disease caused by a novel pathogen created havoc and continues to affect the entire world. As the pandemic progressed, the scientific community was faced by the limitations of existing diagnostic methods. In this review, we have compared the existing diagnostic techniques such as reverse transcription polymerase chain reaction (RT-PCR), antigen and antibody detection, computed tomography scan, etc. and techniques in the research phase like microarray, artificial intelligence, and detection using novel materials; on the prospect of sample preparation, detection procedure (qualitative/quantitative), detection time, screening efficiency, cost-effectiveness, and ability to detect different variants. A detailed comparison of different techniques showed that RT-PCR is still the most widely used and accepted coronavirus detection method despite certain limitations (single gene targeting- in context to mutations). New methods with similar efficiency that could overcome the limitations of RT-PCR may increase the speed, simplicity, and affordability of diagnosis. In addition to existing devices, we have also discussed diagnostic devices in the research phase showing high potential for clinical use. Our approach would be of enormous benefit in selecting a diagnostic device under a given scenario, which would ultimately help in controlling the current pandemic caused by the coronavirus, which is still far from over with new variants emerging. [ABSTRACT FROM AUTHOR]

Airborne fungi are one of the most ubiquitous kinds of inhalant allergens which can result in allergic diseases. Fungi tend to grow in warm and humid environments with regional and seasonal variations. Their nomenclature and taxonomy are related to the sensitization of immunoglobulin E (IgE). Allergic cross-reactivity among different fungal species appears to be widely existing. Fungus-related foods, such as edible mushrooms, mycoprotein, and fermented foods by fungi, can often induce to fungus food allergy syndrome (FFAS) by allergic cross-reactivity with airborne fungi. FFAS may involve one or more target organs, including the oral mucosa, the skin, the gastrointestinal and respiratory tracts, and the cardiovascular system, with various allergic symptoms ranging from oral allergy syndrome (OAS) to severe anaphylaxis. This article reviews the current knowledge on the field of allergic cross-reactivity between fungal allergens and related foods, as well as the diagnosis and treatment on FFAS. [ABSTRACT FROM AUTHOR]

The analysis of trace amounts of proteins based on immunoassays and other methods is essential for the early diagnosis of various diseases such as cancer, dementia, and microbial infections. Here, we propose a light-induced acceleration of antigen-antibody reaction of attogram-level proteins at the solid-liquid interface by tuning the laser irradiation area comparable to the microscale confinement geometry for enhancing the collisional probability of target molecules and probe particles with optical force and fluidic pressure. This principle was applied to achieve a 102-fold higher sensitivity and ultrafast specific detection in comparison with conventional protein detection methods (a few hours) by omitting any pretreatment procedures; 47–750 ag of target proteins were detected in 300 nL of sample after 3 minutes of laser irradiation. Our findings can promote the development of proteomics and innovative platforms for high-throughput bio-analyses under the control of a variety of biochemical reactions. Attogram-level of proteins can be detected using light-induced acceleration of antigen-antibody interactions in a microchannel platform. [ABSTRACT FROM AUTHOR]

Combinatorial biology methods such as phage and yeast display, suitable for the generation and screening of huge numbers of protein fragments and mutated variants, have been useful when dissecting the molecular details of the interactions between antibodies and their target antigens (mainly those of protein nature). The relevance of these studies goes far beyond the mere description of binding interfaces, as the information obtained has implications for the understanding of the chemistry of antibody–antigen binding reactions and the biological effects of antibodies. Further modification of the interactions through combinatorial methods to manipulate the key properties of antibodies (affinity and fine specificity) can result in the emergence of novel research tools and optimized therapeutics. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer immunotherapy, also known as immuno-oncology (IO), has made impressive progress in recent decades and is becoming an essential approach for cancer treatments. For IO drug development, a pertinent preclinical model is indispensable for the rapid and efficient transition from preclinical evaluation through to clinical progress. To date, rodents represent the most-often used models for preclinical evaluation. However, their use presents several drawbacks, including ethical constraints, and time-consuming and costly experiments, which could slow down IO drug development. The aim of our study was to assess the use of the chicken embryo (in ovo) model as an alternative in vivo model for evaluating IO drugs. We confirmed in ovo the anti-tumor efficacy of programmed cell death protein-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) checkpoint inhibitors based on the Chicken Chorioallantoic Membrane (CAM) assay, revealing the pertinence of the chicken embryo model in its use for IO research. (1) Purpose: To assess the use of the chicken embryo (in ovo) model as an alternative in vivo model for immuno-oncology (IO) drug development, focusing on programmed cell death protein-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) immune checkpoint inhibitors. (2) Methods: First, the presence of immune cells in the model was detected through the immunophenotyping of chicken peripheral blood mononuclear cells (PBMCs) based on fluorescence activated cell sorting (FACS) analysis and the immunohistochemistry (IHC) analysis of in ovo tumor-infiltrating lymphocytes. Second, the cross-reactivity between one anti-human PD-1 Ab, pembrolizumab (KEYTRUDA®), and chicken PD-1 was verified through the labelling of chicken splenocytes with pembrolizumab by FACS analysis. Third, the blockade effect of pembrolizumab on chicken PBMCs was assessed in vitro through cytotoxicity assay based on MTT. Fourth, the CAM assay was used to estimate the anti-tumor performance of pembrolizumab through the analyses of tumor growth and chicken immune cell infiltration in tumors. Finally, the efficacy of several PD-1 or PD-L1 inhibitors (nivolumab, atezolizumab and avelumab) on tumor growth was further assessed using the CAM assay. (3) Results: The presence of CD3+, CD4+, CD8+ T lymphocytes and monocytes was confirmed by FACS and IHC analyses. During in vitro assays, pembrolizumab cross-reacted with chicken lymphocytes and induced PD-1/PD-L1 blockade, which permitted the restoration of chicken T-cell's cytotoxicity against human lung cancer H460 tumor cells. All these in vitro results were correlated with in ovo findings based on the CAM assay: pembrolizumab inhibited H460 tumor growth and induced evident chicken immune cell infiltration (with significant chicken CD45, CD3, CD4, CD8 and CD56 markers) in tumors. Furthermore, the potency of the CAM assay was not limited to the application of pembrolizumab. Nivolumab, atezolizumab and avelumab also led to tumor growth inhibition in ovo, on different tumor models. (4) Conclusions: The chicken embryo affords a physiological, immune reactive, in vivo environment for IO research, which allows observation of how the immune system defense against tumor cells, as well as the different immune tolerance mechanisms leading to tumor immune escape. The encouraging results obtained with PD-1/PD-L1 inhibitors in this study reveal the potential use of the chicken embryo model as an alternative, fast, and reliable in vivo model in the different fields of IO drug discovery. [ABSTRACT FROM AUTHOR]

Background Following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination there is significant variability between individuals in protective antibody levels against SARS-CoV-2, and within individuals against different virus variants. However, host demographic or clinical characteristics that predict variability in cross-reactive antibody levels are not well-described. These data could inform clinicians, researchers, and policymakers on the populations most likely to require vaccine booster shots. Methods In an institutional review board–approved prospective observational cohort study of staff at St. Jude Children's Research Hospital, we identified participants with plasma samples collected after SARS-CoV-2 infection, after mRNA vaccination, and after vaccination following infection, and quantitated immunoglobulin G (IgG) levels by enzyme-linked immunosorbent assay to the spike receptor binding domain (RBD) from 5 important SARS-CoV-2 variants (Wuhan Hu-1, B.1.1.7, B.1.351, P.1, and B.1.617.2). We used regression models to identify factors that contributed to cross-reactive IgG against 1 or multiple viral variants. Results Following infection, a minority of the cohort generated cross-reactive antibodies, IgG antibodies that bound all tested variants. Those who did had increased disease severity, poor metabolic health, and were of a particular ancestry. Vaccination increased the levels of cross-reactive IgG levels in all populations, including immunocompromised, elderly, and persons with poor metabolic health. Younger people with a healthy weight mounted the highest responses. Conclusions Our findings provide important new information on individual antibody responses to infection/vaccination that could inform clinicians on populations that may require follow-on immunization. [ABSTRACT FROM AUTHOR]

Molecular dynamics characteristics have important significance in studying the interaction between biomolecules, such as drug screening, environmental monitoring and evaluation of virus infectivity. In this work, a simulation method based on step function is proposed to study the molecular binding and dissociation processes, which is further coupled with surface plasmon wave evanescent field. A complete simulation model is established from biomolecular reaction to surface plasmon resonance (SPR) optical detection, which is consistent with the experimental process. Furthermore, experimental verification studies were carried out on human serum albumin (HSA), a marker of the urinary protein disease. The effects of microchannel size, liquid flow rate, molecular concentration, complex samples and other conditions on the molecular dynamics binding characteristics were studied under the conditions of antibody fixation and antigen–antibody binding reaction. Optimized parameters are obtained such as microchannel size and liquid flow rate, which can save reaction reagents reduce the experimental process and improve the experimental detection accuracy. Therefore, the established simulation and experimental methods include a complete process from biological information to optical information, which is expected to be a powerful tool for molecular interaction analysis in the future. [ABSTRACT FROM AUTHOR]

Inspired by the self/non-self discrimination theory, Forrest et al. proposed a distance-based negative selection algorithm (NSA). However, in the detector generation phase, NSA creates specific antibodies for each antigen based on the mechanism of specific antigen–antibody binding reactions, which lead to an excessive and redundant number of detectors. Moreover, during the detection phase, NSA needs to calculate the matching degree of the antigen with all the detectors, which has a high computational cost and low detection efficiency. This letter presents a novel natural killer cell algorithm (NKA) inspired by the mechanism of NK cells constructing phenotype detectors based on pathogen dose, which is a non-specific immune mechanism. NKA defines dose and phenotype detector, optimizes the detectors based on the memory evolution mechanism of phenotype, then establishes k-d tree for the optimized phenotype, and pathogens only need to match the dose with the nearest phenotype detector. Experimental results reveal that NKA can not only achieve the best performance through fewer detectors but also has a higher efficiency in the training and detection phase, compared with three versions of the distance-based NSA algorithms. Meanwhile, NKA generates comparable results compared with six popular machine learning algorithms. [ABSTRACT FROM AUTHOR]

Enhanced intestinal permeability is a pervasive issue in modern medicine, with implications demonstrably associated with significant health consequences such as sepsis, multiorgan failure, and death. Key issues involve the trigger mechanisms that could compromise intestinal integrity and increase local permeability allowing the passage of larger, potentially dangerous molecules. Heat stress, whether exertional or environmental, may modulate intestinal permeability and begs interesting questions in the context of global climate change, increasing population vulnerabilities, and public health. Emerging evidence indicates that intestinal leakage of digestive enzymes and associated cell dysfunctions––a process referred to as autodigestion––may play a critical role in systemic physiological damage within the body. This increased permeability is exacerbated in the presence of elevated core temperatures. We employed Latent Dirichlet Allocation (LDA) topic modeling methods to analyze the relationship between heat stress and the nascent theory of autodigestion in a systematic, quantifiable, and unbiased manner. From a corpus of 11,233 scientific articles across four relevant scientific journals (Gut, Shock, Temperature, Gastroenterology), it was found that over 1,000 documents expressed a relationship between intestine, enhanced permeability, core temperature, and heat stress. The association has grown stronger in recent years, as heat stress and potential autodigestion are investigated in tandem, yet still by a limited number of specific research studies. Such findings justify the design of future studies to critically test novel interventions against digestive enzymes permeating the intestinal tract, especially the small intestine. [ABSTRACT FROM AUTHOR]