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The gold standard for diagnosis of heartworm (Dirofilaria immitis) infection is the detection of circulating antigen. In most cases, antigen is reliably detectable with routine testing; however, when antigen is bound by circulating antibodies, a false-negative result can be obtained. Immune-complex dissociation (ICD) techniques are used to unbind antigen-antibody complexes, thus allowing detection of the antigen. Heat or acid treatment can be used for ICD. This article reviews the benefits of, and indications for, the use of ICD techniques related to heartworm testing. [ABSTRACT FROM AUTHOR]

Certain chemotherapy agents have an increased potential to cause allergic reactions. These reactions can vary in severity from mild to severe, and a change in treatment may be suggested for the patient to avoid the causative agent going forward. This can lead to suboptimal treatment and a change from first-line therapy to a second-line therapy. In certain scenarios, drug desensitization may be considered to allow for continued administration of a standard-of-care chemotherapy agent to cure or palliate a patient's cancer. [ABSTRACT FROM AUTHOR]

Objectives Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive (MDA5+) dermatomyositis patients exhibit a variety of clinical features. We therefore investigated whether patterns of B-cell epitope recognition are linked to the clinical course of MDA5+ dermatomyositis. Methods Our cross-sectional study used ELISA-based methods to determine the relationship between antibody recognition of overlapping 155 amino acid MDA5 subfragments and clinical features of 24 MDA5+ myositis patients. Correlations between clinical features and standardized anti-MDA5 subfragment antibody titres were assessed via Spearman's rank correlation coefficients. Results Twenty-four MDA5+ patients submitted serum samples within a median of 0 (interquartile range, 0–74) days from the initial clinic visit. In addition to typical dermatomyositis rashes, these patients exhibited muscle symptoms (n  = 11), vascular dysfunction (n  = 9) and interstitial lung disease (ILD) (n  = 16). Female patients exhibited higher titres of antibodies recognizing fragment H (aa 905–1026) compared with male patients. Muscle involvement was associated with higher levels of anti-fragment F (aa 646–801) antibody. Conversely, patients with vascular abnormalities had higher anti-fragment B (aa 130–284) and E (aa 517–671) antibody titres than those without vascular dysfunction. Four patients died due to ILD progression and showed higher anti-fragment A (aa 1–155) antibody titres than the other 20 patients. Differences in the ratio of anti-fragment to anti-full-length MDA5 antibody titres were found for sex (H: anti-MDA5) and vascular dysfunction (anti-fragment B, E: anti-MDA5). Conclusions Various clinical features of MDA5+ dermatomyositis correlated with levels of antibodies targeting selected subfragments of this autoantigen, providing a link between fragment-specific immune responses and disease course. [ABSTRACT FROM AUTHOR]

Background: HLA epitopes are currently in the focus of transplantation immunogenetics. The main reason is the complexity of the HLA system with >38,000 alleles, the number of which increases steadily. These alleles are determined by the current state-of-the art typing methods like second- and third-generation sequencing. Screening for HLA antibodies is hampered by the lack of specific target beads with all possible alleles described. Summary: A way to circumvent the problem is to define HLA epitopes. The number of antibody-confirmed epitopes, on the other hand, was found to be 72 for HLA class I and 74 for HLA class II. Here, we elaborate on the current knowledge on these HLA epitopes. Absolute definitions of these structures are not yet available. Key Messages: Making use of eplets is a comparable way allowing statistical analyses. However, one should keep in mind that the results obtained are approximative or perhaps better associative. Continuous collaboration is needed for the full understanding of the HLA epitopes. The reactivity toward epitopes remains patient-specific. [ABSTRACT FROM AUTHOR]

Cranberries have a long history of use in the prevention of urinary tract infections. Cranberry products vary in proanthocyanidin content, a compound implicated in preventing the adhesion of uropathogenic Escherichia coli (E. coli) to uroepithelial cells. Testing is routinely done by cranberry product formulators to evaluate in vitro bacterial anti-adhesion bioactivity, shelf-life, and potential efficacy of cranberry products for consumer use to maintain urinary tract health. Hemagglutination assays evaluate the anti-adhesion bioactivity of cranberry products by determining how effectively the products prevent agglutination of specific red blood cells with E. coli expressing P-type and Type 1 fimbriae. The current study sought to improve upon an established anti-adhesion assay method by expanding the number of E. coli strains used to broaden potential in vivo efficacy implications and presenting results using photomicrographic data to improve accuracy and build databases on products that are routinely tested. Different lots of cranberry powder ingredient and two formulated products were tested independently for anti-adhesion activity using the established method and the improved method. Positive harmonization of results on the same samples using rigorous controls was achieved and provides the substantiation needed for the cranberry industry to utilize the improved, rapid in vitro testing method to standardize cranberry products for sufficient anti-adhesion bioactivity and maintain consumer confidence. [ABSTRACT FROM AUTHOR]

Body fluid identification plays a crucial role in criminal investigations. Because of their presence in many cases, blood and semen are the most relevant body fluids in forensic sciences. Based on antigen–antibody reactions binding unique proteins for each body fluid, serological assays represent one of the most rapid and highly specific tests for blood and semen. Currently, few studies have assessed the factors affecting body fluid identification by applying these assays. This work aimed to study the effect of different fabrics from clothes and time since deposition on identification through immunochromatographic tests for blood and semen, DNA isolation, and STR profiling from these samples. Body fluids were deposited on black- and white-dyed denim and cotton fabrics, and on leather. Afterward, blood and semen were sampled at 1 day, 30 days, and 90 days after deposition and identified by using the SERATEC® HemDirect Hemoglobin Test and the PSA Semiquant and SERATEC® BLOOD CS and SEMEN CS tests, respectively. Laboratory and crime scene tests presented similar performances for the detection of blood and semen stains on every tested fabric. No differences were found on band intensities between timepoints for all fabrics. It was possible to recover and identify blood and semen samples up to three months after deposition and to obtain full STR profiles from all the tested fabrics. Both body fluid STR profiles showed differences in their quality between 1 and 90 days after deposition for all fabrics except for black cotton for semen samples. Future research will expand the results, assessing body fluid identification on other substrates and under different environmental conditions. [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]

Food allergies are a significant health issue worldwide. In many countries, labeling of primary allergens in food products has been made mandatory to ensure consumer safety. In food manufacturing settings, the lateral flow immunoassay (LFI)—based on antigen–antibody reactions—is a rapid and accurate method for allergen testing and is widely used. Peptide arrays are tools that enable the synthesis of peptides of any sequence on a substrate and high-throughput analysis of their interactions with chemicals. This study aimed to investigate a new application of peptide arrays in the field of food technology, particularly in the development of antibodies for food allergen testing. First, monoclonal antibodies against hen egg ovalbumin, a major food allergen, were produced. Then, using a peptide array, the epitope and specificity of the antibodies were comprehensively and precisely analyzed. Finally, an LFI kit incorporating the antibodies demonstrated both high specificity and detection sensitivity for food allergen testing. These findings indicate that peptide arrays are valuable tools in the development of antibodies for food allergen testing, ensuring reliability and accuracy at the molecular level. [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]

Tumor necrosis factor-alpha (TNF-α) is a cytokine secreted by the macrophages and Th1 cells of the immune system in response to inflammation. Given its significance as a biomarker with elevated levels in physiological fluids in various conditions, there is an increasing demand for a simple and accurate TNF-α detection strategy. In this article, we present a liquid crystal (LC)–based biosensor developed for sensitive TNF-α detection. The biosensor operates as follows: TNF-α and detection antibodies (DAbs) form complexes during preincubation. These complexes then bind with the surface-immobilized capture antibodies (CAbs), facilitating the antigen–antibody reaction between the CAbs and the TNF-α/DAb complexes. This target recognition interaction alters the surface topography, disrupting the vertical orientation of LCs produced by dimethyloctadecyl[3-(trimethoxysilyl)-propyl]ammonium chloride. The orientational change in the LCs can be easily visualized with a polarized optical microscope, resulting in brighter images as TNF-α levels rise. Our results demonstrated a linear range of 5.00–500 pg/mL, with a limit of detection and limit of quantification being 1.08 and 3.56 pg/mL, respectively. Recovery experiments on diluted saliva samples produced reasonable results, with TNF-α recoveries ranging from 97.1% ± 2.58% to 107% ± 5.95%. [ABSTRACT FROM AUTHOR]

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Background Adult hematopoietic cell transplant (HCT) recipients are at high risk for influenza-related morbidity and mortality and have suboptimal influenza vaccine immune responses compared to healthy adults, particularly within 2 years of transplant. Methods This phase II, double-blind, multicenter randomized controlled trial compared 2 doses of high-dose trivalent (HD-TIV) to 2 doses of standard-dose quadrivalent (SD-QIV) influenza vaccine administered 1 month apart in adults 3–23 months post-allogeneic HCT. Hemagglutinin antibody inhibition (HAI) titers were measured at baseline, 4 weeks following each vaccine dose, and approximately 7 months post-second vaccination. Injection-site and systemic reactions were assessed for 7 days post-vaccination. The primary immunogenicity comparison was geometric mean HAI titer (GMT) at visit 3 (4 weeks after the second dose); we used linear mixed models to estimate adjusted GMT ratios (aGMRs) comparing HD-TIV/SD-QIV for each antigen. Results We randomized 124 adults; 64 received SD-QIV and 60 received HD-TIV. Following the second vaccination, HD-TIV was associated with higher GMTs compared to SD-QIV for A/H3N2 (aGMR = 2.09; 95% confidence interval [CI]: [1.19, 3.68]) and B/Victoria (aGMR = 1.61; 95% CI: [1.00, 2.58]). The increase was not statistically significant for A/H1N1 (aGMR = 1.16; 95% CI: [0.67, 2.02]). There was a trend to more injection-site reactions for HD-TIV after the second vaccination compared to SD-QIV (50% vs 33%; adjusted odds ratio [aOR] = 4.53; 95% CI: [0.71, 28.9]), whereas systemic reactions were similar between groups with both injections. Conclusions Adult allogeneic HCT recipients who received 2 doses of HD-TIV produced higher HAI antibody responses for A/H3N2 and B/Victoria compared with 2 doses of SD-QIV, with comparable injection-site or systemic reactions. [ABSTRACT FROM AUTHOR]

Background: Antibody is a considerable approach in the pharmaceutical industry, and many studies have been done on antibody fragment engineering. Objectives: The objective of this study is to evaluate the interaction between antigens and antibodies, which is a necessary step for designing an efficient antibody with suitable properties for targeting cancer cells. Methods: In the current study, the 3-dimensional structure of the displayed-selected scFv antibody was constructed, using Sabpred Antibody Builder. The analysis of interactions between scFv and Cluster of differentiation 24 (CD24) was performed by computational docking and molecular dynamics (MD) simulation. Firstly, docking CD24 antigen to the new scFv antibody was done, using the ClusPro 2.0 web server, and residues involved in the interaction were identified. Secondly, using the GROMACS 4.5.3 package, MD simulations were performed. Results: By analyzing the antigen-antibody complex, the critical amino acids involved in these interactions were recognized. Thus, 15 hydrogen bonds between amino acids in light and heavy chains of antibodies and antigens were identified; most of the amino acids belonged to the complementarity-determining regions (CDRs) regions. Tyr148, which belongs to CDR1 of the VL chain by forming 4 hydrogen bonds with amino acids of the CD24 antigen, was considered an important amino acid in the CD24-scFv complex. Conclusions: Our bioinformatics study identified critical residues involved in antigen-antibody interaction, which could be considered an effective strategy for creating novel efficient fragmented antibodies with improved affinities for the CD24 receptor. [ABSTRACT FROM AUTHOR]

Background. Achieving a suitable medical laboratory index is very important for the prediction of clinical outcome of COVID-19 patients hospitalized to the intensive care unit (ICU). The correlation between neutrophil-to-lymphocyte ratio (NLR) and unfavorable outcome of COVID-19 patients hospitalized to ICU was the aim of this study. Methods. We evaluated a cross-sectional study of 312 COVID-19 patients who were hospitalized to the ICU (confirmed by PCR and CT-Scan), in Babol city, Mazandaran province. WBC, RBC, lymphocyte, neutrophil, monocyte, platelet count, NLR, C-reactive protein (CRP), ESR, MCV, MHC, and other factors were evaluated. Results. Our findings indicated that all patients aged 56 to 69 years with COVID-19 had a significant difference (P < 0.05) in neu, lymph, PLT count, NLR, ESR, Hb, and CRP. Also, NLR was significantly (P < 0.05) correlated with the death or discharge of the ICU hospitalized patients. The cut-off of NLR was 7.02 and the mean of NLR was 11.3 ± 10.93 and 5.8 ± 7.45 in death and discharge COVID-19 patients hospitalized to ICU, respectively. ROC curve indicated that, for NLR, the area under curve was 0.76. Conclusions. Our findings showed that NLR can be utilized as a clinical laboratory predictive parameter for mortality of COVID-19 patients admitted to ICU. [ABSTRACT FROM AUTHOR]

Background: We have identified and reported a novel antigen, nonprotein‐specific secreted EP1‐like glycoprotein (51 kDa), for lettuce‐related respiratory allergy. Objective: We aimed to identify a novel antigen for lettuce‐related respiratory allergy that is different from epidermis‐specific secreted EP1‐like glycoprotein. Methods: Immunoblotting was performed using an immunoglobulin E‐specific antibody. The antigen‐antibody reaction was confirmed by means of enzyme‐linked immunosorbent assaying. LC‒MS/MS analysis was carried out to detect a novel protein found in sera from 3 of 13 patients with lettuce‐related respiratory allergy. Finally, we purified a novel protein from Escherichia coli. Results: Immunoblotting assays showed common bands of 17 kDa in the sera of 3 of 13 patients. An enzyme‐linked immunosorbent assay confirmed that the patient sera reacted with lettuce latex juice. A 17 kDa protein band that showed antigenic reactivity in 3 of 13 patient sera was identified as a kirola‐like protein by LC‒MS/MS. In addition, although we purified this protein, we failed to show the inhibitory effect. Conclusion: A 17 kDa protein that is a potentially novel antigen of lettuce‐associated respiratory allergy was identified. In further studies, we will focus on purifying this novel protein to diagnose lettuce allergy. Key message: Immunoblotting analysis showed common bands at 17 kDa for lettuce latex and patient serum.The 17 kDa protein bands were identified as kirola‐like protein by LC‒MS/MS.We purified the kirola‐like protein. [ABSTRACT FROM AUTHOR]

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]

Das aktuelle Update der Autoimmun-Analyzer-Tabelle stellt 14 Autoimmunanalyzer vor, auf denen sechs verschiedene Nachweisverfahren für die Autoimmundiagnostik etabliert sind. Die Autoimmundiagnostik wird zwar kontinuierlich weiterentwickelt, doch beruhen alle Nachweisverfahren auf einer Antigen-Antikörper-Reaktion. [ABSTRACT FROM AUTHOR]

Objectives: We examined the frequency of cross-reactions to Rickettsia typhi in patients with Japanese spotted fever (JSF) and evaluated the differences between two rickettsiae using antibody endpoint titers. Methods: Patients’ immunoglobulin (Ig)M and IgG titers against Rickettsia japonica and Rickettsia typhi in two phases were measured using an indirect immunoperoxidase assay at two reference centers for rickettsiosis in Japan. Cross-reaction was defined as a higher titer against R. typhi in convalescent sera than in acute sera among patients fulfilling the criteria for JSF diagnosis. The frequencies of IgM and IgG were also evaluated. Results: Approximately 20% of cases showed positive cross-reactions. A comparison of antibody titers revealed the difficulty in identifying some positive cases. Conclusion: Cross-reactions of 20% in serodiagnosis may lead to the misclassification of rickettsial diseases. However, with the exception of some cases, we were able to successfully differentiate JSF from murine typhus using each endpoint titer.

Salmonella enterica serovar Dublin is a cattle-adapted serovar, and some infected cattle can become asymptomatic carriers. Identification of carrier animals is important for preventing the spread of infection within a farm, but low diagnostic sensitivity of the fecal culture method is problematic. In this study, we investigated isolation methods of four S. enterica Dublin strains. Selective enrichment using the tetrathionate broth showed better performance than RappaportVassiliadis R10 broth, but one of the strains was not detectable. Since isolation of such strains by selective enrichment can be difficult, we designed a method using immuno-plates that concentrates S. enterica Dublin by antigen-antibody reaction. Our method is able to detect approximately 200 clony-forming units of S. enterica Dublin in 0.1 g of cattle feces. If S. enterica Dublin was isolated from cattle with clinical signs, the method to identify carriers in the farm should be based on the growth kinetics of the target S. enterica Dublin strain. [ABSTRACT FROM AUTHOR]

Anti-glomerular basementmembrane (GBM) disease is a rare but life-threatening autoimmune disorder characterized by rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. Renal biopsies of anti-GBM patients predominantly show linear deposition of IgG and complement component 3 (C3), indicating a close association between antigen-antibody reactions and subsequent complement activation in the pathogenesis of the disease. All three major pathways of complement activation, including the classical, lectin, and alternative pathways, are involved in human anti-GBM disease. Several complement factors, such as C3, C5b-9, and factor B, show a positive correlation with the severity of the renal injury and act as risk factors for renal outcomes. Furthermore, compared to patients with single positivity for anti-GBM antibodies, individuals who are double-seropositive for anti-neutrophil cytoplasmic antibody (ANCA) and anti-GBM antibodies exhibit a unique clinical phenotype that lies between ANCA-associated vasculitis (AAV) and anti-GBM disease. Complement activation may serve as a potential "bridge" for triggering both AAV and anti-GBM conditions. The aim of this article is to provide a comprehensive review of the latest clinical evidence regarding the role of complement activation in anti-GBM disease. Furthermore, potential therapeutic strategies targeting complement components and associated precautions are discussed, to establish a theoretical basis for complement- targeted therapies. [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]

Background: Alloimmunization against blood group antigens is an important non-infectious complication of blood transfusion, and early detection of these alloantibodies by antibody screening before transfusion is crucial. Identifying which underlying factors will affect the occurrence of alloimmunization will be necessary to manage this event as accurately as possible. We aimed to assess the prevalence rate and main determinants of RBC alloimmunization among patients referred to a large referral blood bank in Iran. Methods: This retrospective cross-sectional study was conducted on all patients referred to a blood bank at Imam Khomeini Hospital between October 2018 and September 2020. Information was collected by referring to the archives of the hospital information system as well as the documents recorded at the blood bank ward and reviewed by two pathologists and completed documents. Results: In total, 39 270 cases were cross-matched. Accordingly, the frequency of alloimmunization cases was equal to 220 cases, which indicated a prevalence of 0.56%. The most common alloantibodies were anti-K (43.2%, 95% CI: 36.8-49.5), anti-E (34%, 95% CI: 27.7-40.5), and anti-C (16.3%, 95% CI: 11.4-21.4). Among patients with positive alloimmunization, the most common blood groups were blood group B (34.6%), followed by blood group A (34.1%). Most of these patients were Rh-positive (77.3%). In patients with positive alloimmunization, the frequency of hemoglobinopathy was estimated to be 37.7%. Frequent blood transfusions were found in 42.2%, a history of malignancy in 17.3%, graft history in 11.3%, and a history of pregnancy in 35.0%. Conclusion: Alloimmunization was more prevalent and more predictable among patients with hemoglobinopathies and those receiving recurrent transfusions. Therefore, a history of repeated blood transfusions should be regarded as a risk factor contributing to alloimmunization. [ABSTRACT FROM AUTHOR]

Background: Antenatal care provides unique opportunities to assess severe acute respiratory syndrome coronavirus 2 seroprevalence and antibody response duration after natural infection detected during pregnancy; transplacental antibody transfer may inform peripartum and neonatal protection. We estimated seroprevalence and durability of antibodies from natural infection (anti-nucleocapsid immunoglobulin G) among pregnant people, and evaluated transplacental transfer efficiency. Objective and design: We conducted a cross-sectional study to measure severe acute respiratory syndrome coronavirus 2 seroprevalence, and a prospective cohort study to longitudinally measure anti-nucleocapsid immunoglobulin G responses and transplacental transfer of maternally derived anti-nucleocapsid antibodies. Methods: We screened pregnant people for the seroprevalence study between 9 December 2020 and 19 June 2021 for anti-nucleocapsid immunoglobulin G in Seattle, Washington. We enrolled anti-nucleocapsid immunoglobulin G positive people from the seroprevalence study or identified through medical records with positive reverse transcription polymerase chain reaction or antigen positive results in a prospective cohort between 9 December 2020 and 9 August 2022. Results: In the cross-sectional study (N = 1284), 5% (N = 65) tested severe acute respiratory syndrome coronavirus 2 anti-nucleocapsid immunoglobulin G positive, including 39 (60%) without prior positive reverse transcription polymerase chain reaction results and 42 (65%) without symptoms. In the prospective cohort study (N = 107 total; N = 65 from the seroprevalence study), 86 (N = 80%) had anti-nucleocapsid immunoglobulin G positive results during pregnancy. Among 63 participants with delivery samples and prior anti-nucleocapsid positive results, 29 (46%) were anti-nucleocapsid immunoglobulin G negative by delivery. Of 34 remaining anti-nucleocapsid immunoglobulin G positive at delivery with paired cord blood, 19 (56%) had efficient transplacental anti-nucleocapsid immunoglobulin G antibody transfer. Median time from first anti-nucleocapsid immunoglobulin G positive to below positive antibody threshold was 19 weeks and did not differ by prior positive reverse transcription polymerase chain reaction status. Conclusions: Maternally derived severe acute respiratory syndrome coronavirus 2 antibodies to natural infection may wane before delivery. Vaccines are recommended for pregnant persons to reduce severe illness and confer protection to infants. [ABSTRACT FROM AUTHOR]

The timing of maternal pertussis vaccination influences the titers of cord-blood anti-pertussis antibodies. Whether it affects their avidity is unknown. We demonstrate in 298 term and 72 preterm neonates that antibody avidity is independent of the timing of maternal vaccination, whether comparing second with third trimester or intervals before birth. [ABSTRACT FROM AUTHOR]

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]

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]

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]

Analysis of the specificity and kinetics of neutralizing antibodies (nAbs) elicited by SARS-CoV-2 infection is crucial for understanding immune protection and identifying targets for vaccine design. In a cohort of 647 SARS-CoV-2-infected subjects, we found that both the magnitude of Ab responses to SARS-CoV-2 spike (S) and nucleoprotein and nAb titers correlate with clinical scores. The receptor-binding domain (RBD) is immunodominant and the target of 90% of the neutralizing activity present in SARS-CoV-2 immune sera. Whereas overall RBD-specific serum IgG titers waned with a half-life of 49 days, nAb titers and avidity increased over time for some individuals, consistent with affinity maturation. We structurally defined an RBD antigenic map and serologically quantified serum Abs specific for distinct RBD epitopes leading to the identification of two major receptor-binding motif antigenic sites. Our results explain the immunodominance of the receptor-binding motif and will guide the design of COVID-19 vaccines and therapeutics.

Proximity‐induced chemical reactions are site‐specific and rapid by taking advantage of their high affinity and highly selective interactions with the template. However, reactions induced solely by antibody–antigen interactions have not been developed. Herein, we propose a biepitopic antigen‐templated chemical reaction (BATER) as a novel template reaction. In BATER, reactive functional groups are conjugated to two antibodies that interact with two epitopes of the same antigen to accelerate the reaction. We developed a method for visualizing the progress of BATER using fluorogenic click chemistry for optimal antibody selection and linker design. The reaction is accelerated in the presence of a specific antigen in a linker length‐dependent manner. The choice of the antibody epitope is important for a rapid reaction. This design will lead to various applications of BATER in living systems. [ABSTRACT FROM AUTHOR]

Objective To define the clinical phenotype of SSc patients with antibodies against Sjogren's syndrome (SS)/scleroderma autoantigen 1 (SSSCA1), and to examine the association between these antibodies and cancer in SSc patients. Methods We conducted a case–control study using data from 209 patients with SSc and cancer, and 205 SSc patients without cancer. All were randomly selected from the Johns Hopkins Scleroderma Center Research Registry. Antibodies against SSSCA1 were assayed by immunoprecipitation of 35S-methionine-labelled protein generated by in vitro transcription and translation. We performed logistic regression analysis to examine the relationship between anti-SSSCA1 antibodies and cancer. Results Among the 414 study patients, 31 (7%) were anti-SSSCA1 antibody positive. Antibody-positive patients were more likely to have severe RP, a lower minimum ejection fraction, a trend towards more severe heart involvement and a lower baseline diffusing capacity of the lungs for carbon monoxide percent predicted than anti-SSSCA1-negative patients. Patients with cancer were significantly more likely to be anti-SSSCA1 positive compared with those without cancer [22/209 (11%) vs 9/205 (4%), respectively; P  = 0.018]. Among patients with cancer, there was a trend towards longer cancer–SSc interval in anti-SSSCA1-positive patients compared with anti-SSSCA1-negative patients. Patients with anti-SSSCA1 antibodies had an increased adjusted risk of cancer (odds ratio 2.46, 95% CI 1.06, 5.70) compared with anti-SSSCA1-negative patients. Conclusions These data suggest anti-SSSCA1 antibody status may be of utility as a cancer biomarker in SSc. Anti-SSSCA1-positive patients with SSc may be more likely to have severe Raynaud's and cardiac involvement. [ABSTRACT FROM AUTHOR]

BACKGROUND: Red blood cell (RBC) group systems are depicted by antigens on the surface of RBCs, which when transfused to a recipient that lacks them, can result in alloimmunization. Thus, transfusion of matched RBC components to the recipient is recommended, especially for the more immunogenic blood group antigens, such as Rh (E, e, C, and c), Kell, Kidd, Duffy, and MNS. AIMS: The aim of this study was to perform the blood group genotyping from blood samples of 12 polytransfused patients whose phenotyping was inconclusive or incomplete. METHODS: The amplicons were amplified by polymerase chain reaction-sequence-specific primers for the following alleles: RHCE (RHCE * C, RHCE * c, RHCE * E, and RHCE * e), KEL (KEL * 01 and KEL * 02), FY (FY * 01 and FY * 02), and KID (JK * 01 and JK * 02), in addition to the GATAI-mutated gene (FY * 02N.01). RESULTS: Discrepancies were found in the Rh (E) and Kidd systems, in addition to cases of Fyb antigen silencing attributed to the GATA mutation, which was present in all individuals with Fy (a-b-) phenotype. The technique also solved the inconclusive phenotyping caused by mixed-field agglutination. CONCLUSION: The results show the contribution of blood group genotyping in complex immunohematology cases, optimizing the delivery of RBC components suitable for transfusion safety, and expanding the number of compatible donors for patients with the Fy (a-b) phenotype related to the FY (02N.01) allele. [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]

The early detection of infectious diseases and microorganisms is critical for effective disease treatment, control, and prevention. Currently, nucleic acid testing and antigen–antibody serum reaction are the two methods most commonly used for the detection of infectious diseases. The former is highly accurate, specific, and sensitive, but it is time-consuming, expensive, and has special technician and instrument requirements. The latter is rapid and economical, but it may not be accurate and sensitive enough. Therefore, it is necessary to develop a quick and on-site diagnostic test for point-of-care testing (POCT) to enable the clinical detection of infectious diseases that is accurate, sensitive, convenient, cheap, and portable. Here, CRISPR/Cas-based detection methods are detailed and discussed in depth. The powerful capacity of these methods will facilitate the development of diagnostic tools for POCT, though they still have some limitations. This review explores and highlights POCT based on the class 2 CRISPR/Cas assay, such as Cas12 and Cas13 proteins, for the detection of infectious diseases. We also provide an outlook on perspectives, multi-application scenarios, clinical applications, and limitations for POCT based on class 2 CRISPR/Cas technology. [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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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]