Unveiling the secrets of adeno-associated virus: novel high-throughput approaches for the quantification of multiple serotypes

Adeno-associated virus (AAV) vectors are among the most prominent viral vectors for in vivo gene therapy, and their investigation and development using high-throughput techniques have gained increasing interest. However, sample throughput remains a bottleneck in most analytical assays. In this study, we compared commonly used analytical methods for AAV genome titer, capsid titer, and transducing titer determination with advanced methods using AAV2, AAV5, and AAV8 as representative examples. For the determination of genomic titers, we evaluated the suitability of qPCR and four different digital PCR methods and assessed the respective advantages and limitations of each method. We found that both ELISA and bio-layer interferometry provide comparable capsid titers, with bio-layer interferometry reducing the workload and having a 2.8-fold higher linear measurement range. Determination of the transducing titer demonstrated that live-cell analysis required less manual effort compared with flow cytometry. Both techniques had a similar linear range of detection, and no statistically significant differences in transducing titers were observed. This study demonstrated that the use of advanced analytical methods provides faster and more robust results while simultaneously increasing sample throughput and reducing active bench work time.

Toxoplasma gondii seroprevalence in reindeer (Rangifer tarandus tarandus L.) in northern Sweden: a cross-sectional study from 2014

BACKGROUND

Toxoplasma gondii is a parasitic protozoan that can infect a wide range of warm-blooded animals, including humans. The infection with T. gondii, is of particular concern due to its potential impact on human and animal health. In Sweden, semi-domesticated reindeer (Rangifer tarandus tarandus L.) is an important species both economically and culturally, but susceptibility to Toxoplasma infection and seroprevalence in reindeer herds remain relatively understudied.

RESULTS

A total of 528 reindeer, sampled at two slaughterhouses in Sweden in 2014, were investigated for antibodies to T. gondii. Specific antibodies to T. gondii were found in 5 of 209 (2.3%) tested adult reindeer and in 6 of 308 (1.9%) tested calves, giving an apparent total prevalence of 2.1% (95% confidence interval 1.1-3.8%). None of four putative risk factors studied (sex, age, type of grazing area, county) were statistically associated with T. gondii seroprevalence.

CONCLUSIONS

Swedish semi-domesticated reindeer are exposed to T. gondii and may harbour infectious tissue cysts. To mitigate the risk of T. gondii infection in consumers, reindeer meat should be frozen or cooked thoroughly before consumption. The global climate change may influence the seroprevalence and possible associated risk factors for T. gondii in reindeer. To be able to manage the risk and get better advice to the consumers there is a need for further investigations covering the whole spectra of herding conditions for reindeer.

M13KO7 bacteriophage enables Potato Virus Y detection

IMPORTANCE

In this study, we confirmed the binding of M13KO7 to Potato virus Y (PVY) using enzyme-linked immunosorbent assay. M13KO7 is a "bald" bacteriophage in which no recombinant antibody is displayed. M13KO7 is easy to propagate by using Escherichia coli, making this method more reasonable in economic perspective. Based on this study, we suggest that M13KO7 detection system has applicability as a novel biological tool for the detection of PVY.

High Seroprevalence of Severe Fever with Thrombocytopenia Syndrome Virus Infection among the Dog Population in Thailand

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne zoonotic disease caused by the SFTS virus (SFTSV). In Thailand, three human cases of SFTS were reported in 2019 and 2020, but there was no report of SFTSV infection in animals. Our study revealed that at least 16.6% of dogs in Thailand were seropositive for SFTSV infection, and the SFTSV-positive dogs were found in several districts in Thailand. Additionally, more than 70% of the serum samples collected at one shelter possessed virus-neutralization antibodies against SFTSV and the near-complete genome sequences of the SFTSV were determined from one dog in the shelter. The dog SFTSV was genetically close to those from Thailand and Chinese patients and belonged to genotype J3. These results indicated that SFTSV has already spread among animals in Thailand.

Development and evaluation of serological screening based on one dried plasma spot for HIV, syphilis, and HCV

BACKGROUND

In the effort to prevent and control HIV/AIDS, China has established a national sentinel surveillance system. However, some sentinel sites face limitations in environmental resources and accessibility, prompting the exploration of alternative sample strategies. Dried plasma spots (DPS) samples are viewed as promising alternatives to traditional plasma samples due to their advantages, including sample stability, easy storage, and convenient transport. This study aims to develop a method for screening HIV, Treponema pallidum (TP), and Hepatitis C Virus (HCV) using DPS samples and assess their performance.

METHODS

Based on existing commercial assay kits, a detection method was established through the optimization of experimental parameters, including the amount of plasma on filter paper, the volume of elution solution applied to dried plasma spots, the size of dried plasma spots, elution solution volume, elution solution components, elution temperature, and elution time. A series of laboratory evaluation panels were constructed for laboratory assessments, including the laboratory basic panel, laboratory interference panel, and laboratory precision panel. Additionally, clinical samples were used for evaluation.

RESULTS

Optimal conditions for DPS sample extraction were: plasma volume, 100 µL; DPS size, whole spot; eluent volume, 500 µL; eluent, PBS with 1‰ Tween20; elution time, 2 h; elution temperature, room temperature. A total of 619 paired plasma/DPS samples were tested by both methods. The DPS-based ELISA method exhibited 100% sensitivity/specificity for HIV, 98.6%/100% for TP, and 99.6%/100% for HCV. Kappa values between the plasma samples and DPS samples were 100% for HIV, 99% for TP, and 100% for HCV. The DPS-based ELISA method failed to detect 1 HCV mono-infected sample and TP in 1 HIV/HCV/TP co-infected sample. For the HIV/HCV/TP co-infected sample, the S/CO in the plasma sample was 2.143 and in the DPS sample was 0.5. For HCV, the S/CO (sample OD/cut-off) was 3.049 in the plasma sample and 0.878 in the DPS sample.

CONCLUSIONS

A single DPS, following one-time standardized processing, can be used to detect HIV, HCV, and TP. Researching and establishing laboratory testing methods better suited for China's sentinel surveillance have significant practical applications in improving HIV testing in resource-constrained environments.

Identifying secreted biomarkers of dopaminergic ventral midbrain progenitor cells

BACKGROUND

Ventral midbrain (VM) dopaminergic progenitor cells derived from human pluripotent stem cells have the potential to replace endogenously lost dopamine neurons and are currently in preclinical and clinical development for treatment of Parkinson's Disease (PD). However, one main challenge in the quality control of the cells is that rostral and caudal VM progenitors are extremely similar transcriptionally though only the caudal VM cells give rise to dopaminergic (DA) neurons with functionality relevant for cell replacement in PD. Therefore, it is critical to develop assays which can rapidly and reliably discriminate rostral from caudal VM cells during clinical manufacturing.

METHODS

We performed shotgun proteomics on cell culture supernatants from rostral and caudal VM progenitor cells to search for novel secreted biomarkers specific to DA progenitors from the caudal VM. Key hits were validated by qRT-PCR and ELISA.

RESULTS

We identified and validated novel secreted markers enriched in caudal VM progenitor cultures (CPE, LGI1 and PDGFC), and found these markers to correlate strongly with the expression of EN1, which is a predictive marker for successful graft outcome in DA cell transplantation products. Other markers (CNTN2 and CORIN) were found to conversely be enriched in the non-dopaminergic rostral VM cultures. Key novel ELISA markers were further validated on supernatant samples from GMP-manufactured caudal VM batches.

CONCLUSION

As a non-invasive in-process quality control test for predicting correctly patterned batches of caudal VM DA cells during clinical manufacturing, we propose a dual ELISA panel measuring LGI1/CORIN ratios around day 16 of differentiation.

Domestic and wild animal samples and diagnostic testing for SARS-CoV-2

From the first cases in 2019, COVID-19 infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have resulted in over 6 million human deaths in a worldwide pandemic. SARS-CoV-2 is commonly spread from human to human through close contact and is capable of infecting both humans and animals. Worldwide, there have been over 675 animal outbreaks reported that resulted in over 2000 animal infections including domestic and wild animals. As the role of animal infections in the transmission, pathogenesis, and evolution of SARS-CoV-2 is still unfolding, accurate and reliable animal diagnostic tests are critical to aid in managing both human and animal health. This review highlights key animal samples and the three main diagnostic approaches used for animal testing: PCR, serology, and Next Generation Sequencing. Diagnostic results help inform (often difficult) clinical decision-making, but also possible ways to mitigate spread among pets, food supplies, or wildlife. A One Health approach has been key to monitoring the SARS-CoV-2 pandemic, as consistent human-animal interactions can lead to novel variants. Having multiple animal diagnostic tests for SARS-CoV-2 available is critical to ensure human, animal, and environmental health.

Clinical profile and outcomes of Scrub typhus in pregnant women presenting to a tertiary care hospital of North India

Scrub typhus, caused by Orientia tsutsugamushi, is a re-emerging endemic zoonosis in the Asia Pacific region. It is a febrile condition ranging in severity from mild to severe, with fatality rates as high as 30%. The present study aims towards analysing the clinical profile and pregnancy outcomes in 27 cases of scrub typhus admitted to a tertiary care centre in North India. The medical records of 27 pregnant women who had scrub typhus were analysed. The IgM ELISA was used to look for IgM antibodies to Orientia tsutsugamushi in the patient's serum sample. An optical density of more than or equal to 0.468 was considered as positive. Majority of the pregnant females delivered healthy and live babies. However, poor foetal outcomes were observed in four (14.8%) cases with intrauterine deaths occurring in two (7.4%) cases and still birth in one (3.7%) case, while one (3.7%) patient had spontaneous abortion. Maternal mortality was reported in one patient (3.7%) due to a delay in diagnosis. In endemic settings, a strong index of suspicion for scrub typhus is necessary in pregnant females presenting with fever. The key to reducing morbidity in both the mother and foetus is early diagnosis and treatment.Impact StatementWhat is already known on this subject? Scrub typhus is a febrile condition ranging in severity from mild to severe, with 30% mortality in untreated patients.What do the results of this study add? Majority of the pregnant females delivered healthy and live babies. However, poor foetal outcomes were observed in four (14.8%) cases with intrauterine deaths occurring in two (7.4%) cases and still birth in one (3.7%) case, while one (3.7%) patient had spontaneous abortion. Maternal mortality was reported in one patient (3.7%) due to a delay in diagnosis.What are the implications of these findings for clinical practice and/or further research? In endemic settings, a strong index of suspicion for scrub typhus is necessary for pregnant females presenting with fever. The key to reducing morbidity in both the mother and foetus is early diagnosis and treatment.

Assessment of crustacean allergen detection methods: cross reactivity with edible insect samples

Increased interest in consumption of insects in recent years has led to an increased focus on associated food safety concerns, and allergy is one of the most relevant. In the United States, crustacean shellfish are regulated as a major allergenic food group per the Food, Drug, and Cosmetic (FD&C) Act. Insects and crustacean shellfish are both arthropods, and clinical cross-reactivity between the two groups has been demonstrated. The goal of this work was to establish whether that clinical cross-reactivity translates into analytical cross-reactivity with detection assays targeting crustacean shellfish allergens. Edible insect samples were analyzed using four different crustacean allergen detection methods: Multi-Analyte Profiling Food Allergen Detection Assay (xMAP FADA), enzyme-linked immunosorbent assay (ELISA), western blot, and real-time polymerase chain reaction (PCR). Results indicate that the immunoassay-based xMAP FADA, ELISA, and western blot were susceptible to cross-reactivity, while the DNA-based PCR methods had minimal reactivity with insect samples. These results confirm that edible insects show analytical cross-reactivity with the immunoassays which may result in false positive detection of crustacean allergens in insect samples. Confirmation using DNA-based PCR, which shows little to no cross-reactivity, clarifies ambiguous results.

Serological and molecular survey of canine distemper virus in red foxes (Vulpes vulpes): Exploring cut-off values and the use of protein A in ELISA tests

The wide distribution and ecological plasticity of the red fox (Vulpes vulpes) make it a potential reservoir for many infectious diseases shared with domestic and wild carnivores. One of such diseases is canine distemper, which is caused by an RNA virus and its main domestic reservoir is the dog. However, other carnivores can also participate in its maintenance, as shown by the recent upsurge of reported cases in wildlife in many parts of the world, and by the fact that red foxes may act as true reservoirs for canine distemper virus (CDV). The lack of validated serological tests for wildlife or other non-target species may be a handicap for monitoring this virus. In this study, serological assays were compared in 147 red fox sera using a commercial ELISA validated for its use in dogs and a non-specific modified ELISA with Protein A peroxidase conjugate to detect bound antibodies. In addition, the presence of CDV RNA in brain, spleen, lung, and liver samples from 144 foxes was investigated by a RT-qPCR. Through the comparison of the results of both ELISAs and the use of a finite mixture model of the optical density values obtained by both techniques, we adjusted the cut-off point of the commercial ELISA to obtain the seroprevalence in foxes. The overall seroprevalence detected was 53.7% (79/147) and 57.1% (84/147) by the commercial and modified ELISA, respectively, with a moderate agreement according to Cohen's Kappa statistic (κ = 0.491, z = 5.97, p < 0.0001). CDV RNA was detected in 30 out of 144 foxes, which resulted in 20.8% of CDV-infected foxes. At individual level, the results obtained by relating the serological status and the presence/absence of RNA in different organs were explained in terms of the pathogenesis of the infection. Our results highlight the convenience of adjusting the cut-off point when using an ELISA assay developed in domestic dogs for its use in foxes. Moreover, Protein A is confirmed to be a good alternative to be used in red foxes, presenting a good reactivity towards its IgG.

Evaluation of a New Aptamer-Based Array for Soluble Suppressor of Tumorgenicity (ST2) and N-terminal Pro-B-Type Natriuretic Peptide (NTproBNP) in Heart Failure Patients

BACKGROUND

Recent advances in multi-marker platforms offer faster data generation, but the fidelity of these methods compared to the ELISA is not established. We tested the correlation and predictive performance of SOMAscan vs. ELISA methods for NTproBNP and ST2.

METHODS

Patients ≥ 18 years with heart failure and ejection fraction < 50% were enrolled. We tested the correlation between SOMA and ELISA for each biomarker and their association with outcomes.

RESULTS

There was good correlation of SOMA vs. ELISA for ST2 (ρ = 0.71) and excellent correlation for NTproBNP (ρ = 0.94). The two versions of both markers were not significantly different regarding survival association. The two ST2 assays and NTproBNP assays were similarly associated with all-cause mortality and cardiovascular mortality. These associations remained statistically significant when adjusted for MAGGIC risk score (all p < 0.05).

CONCLUSION

SOMAscan quantifications of ST2 and NTproBNP correlate to ELISA versions and carry similar prognosis.

Serological and molecular detection of Toxoplasma gondii in ß. thalassemia patients

Toxoplasma gondii is a worldwide opportunistic protozoan causing life-threatening infection in immunocompromised patients, while frequently asymptomatic in immunocompetent individuals. The current study aimed to detect T. gondii; serologically and molecularly in ß. thalassemia patients and evaluate the association of infection with some hematological parameters in these patients. Blood samples were collected from 100 ß. thalassemia patients. Serological diagnosis of T. gondii using ELISA for IgG and IgM antibodies was performed. Molecular diagnosis by Real-Time (RE) PCR was performed using specifically designed primers amplifying 389 bp fragments of Toxoplasma genome. 45 patients (45%) had anti-Toxoplasma IgG antibodies with no detectable IgM antibodies while both anti-Toxoplasma IgM and IgG antibodies were noticed in 10 patients (10%). IgM only antibodies were discovered in two cases (2%). The total seropositivity rate among patients was 57%. RE PCR analysis revealed Toxoplasma DNA in 20% out of 100 patients. PCR and serological examination showed slight agreement. A statistically significant relation was observed between the results of IgG and IgM ELISA and PCR for the detection of T. gondii infection among patients with ß. thalassemia. None of the studied risk factors (age, gender, contact with cats, consumption of undercooked meat) or hematological parameters (ESR, anemia degree, ferritin level, type of blood transfusion, spleen status) showed statistically significant association with Toxoplasma infection. It can be concluded that patients with thalassemia have a high risk of infection with T. gondii. RE PCR should be used as a diagnostic method in association with serology especially in immunocompromised patients to increase sensitivity.

Investigation of the effect of mutual vaccination with pest des petits ruminants and polyvalent foot and mouth disease vaccines on the immune response of sheep

Background

Pest des petits ruminants (PPRs) and foot and mouth disease (FMD) are two viral infectious diseases affecting sheep dramatically causing great economic losses. Therefore, attention should be directed toward their control, especially through the application of well-designed vaccination schedules with specific potent vaccines.

Aim

Determination of the possibility of sheep vaccination with PPR and FMD vaccines in a mutual schedule.

Methods

Different groups of sheep have vaccinated with live attenuated PPR vaccine and inactivated polyvalent FMD vaccine in a mutual manner (one before the other at weekly intervals or simultaneously) followed by monitoring of the induced immunity to both vaccines using serum neutralization test (SNT) and enzyme linked immune sorbent assay (ELISA).

Results

SNT and ELISA revealed that there was no antagonizing effect of any vaccine on the immune response to the mutual vaccination of sheep to the other where the obtained antibody titers in single vaccinated sheep groups were similar to those in the simultaneous vaccinated group.

Conclusion

Simultaneous vaccination of sheep with PPR and polyvalent FMD vaccine is of applicable benefit saving time, effort, and stress factors on the animals.

Development of a recombinant protein-based ELISA for detection of antibodies against bovine herpesvirus 6 (BoHV6)

Introduction

Bovine herpesvirus 6 (BoHV6) belongs to the Herpesviridae family, Gammaherpesvirinae subfamily and Macavirus genus. It is common in cattle, but was also detected in American bison (Bison bison) and water buffalo (Bubalus bubalis). The aim of the experiment was to develop an ELISA for serological examination of cattle sera for the presence of anti-BoHV6 specific antibodies.

Material and Methods

Viral DNA from a BoHV6-positive cow was amplified by qPCR and the resulting fragments of the gB and gH genes encoding glycoproteins B and H (gB and gH) were cloned into the pLATE52 vector to express recombinant gB (rgB) and gH (rgH) in Rosetta (DE3) E. coli. The expressed recombinant proteins were used as antigens in the developed ELISA.

Results

The proteins expressed had the expected molecular weight. A total of 143 sera were examined, and 141 of them were positive, according to the chosen cut-off values of 9% and 10% for the sample-to-positive ratios of the rgB and rgH antigens, respectively.

Conclusion

The rgB and rgH recombinant antigens of BoHV6 were successfully expressed in E. coli and successfully used in a newly developed ELISA.

A comparative study of serological tests used in the diagnosis of Toxoplasma gondii infection in small ruminants evidenced the importance of cross-reactions for harmonizing diagnostic performance

Toxoplasma gondii is a major foodborne zoonotic pathogen that can be transmitted through the consumption of raw or undercooked meat of small ruminants, among others. Serology has been suggested as an epidemiological indicator and several tests are available nowadays. However, there is no comparative study with the most used ones. Therefore, the objective of this study was to develop and validate two in-house tests (Western blot -TgSALUVET WB- and ELISA -TgSALUVET ELISA 2.0-) and perform a comparative study including such tests and four commercial ELISA kits (IDScreen®, PrioCHECK®, Pigtype® and IDEXX). First, a specific pattern of recognition of immunodominant antigens by TgSALUVET WB was determined with serum panels of noninfected sheep and sheep infected with T. gondii or Neospora caninum. Next, TgSALUVET WB was used as a reference to preliminary validate TgSALUVET ELISA 2.0 using sera from sheep and goats naturally infected with T. gondii. Then, the abovementioned sheep serum panels were analyzed by all tests and subjected to TG-ROC analyses and agreement tests, and cross-reactivity with the anti-N. caninum IgGs was studied. All the techniques were accurate enough for the cutoff values initially suggested with all serum panels (Se and Sp ≥ 94%), except for PrioCHECK®, which showed 83% Sp. However, a cutoff readjustment improved their diagnostic performance. Additionally, cross-reactions between anti-N. caninum antibodies and T. gondii antigens were detected with all tests. Thus, a second cutoff readjustment was carried out and the use of both readjusted cutoff values is recommended to obtain comparable data and avoid false-positive results.

Antibody response to enterotoxigenic Bacteroides fragilis of Filipino colorectal cancer patients

Background

Several species of the gut microbiota have been implicated in colorectal cancer (CRC) development. The anaerobic bacterium enterotoxigenic Bacteroides fragilis (ETBF), has been identified to produce fragilysin, a toxin known to cleave E-cadherin, thereby leading to carcinogenesis.

Objective

To determine the antibody response of CRC patients against ETBF to ascertain whether significant difference exists or whether antibody response is related to tumor grade and tumor stage.

Methods

Informed consent was obtained from histologically confirmed CRC casesand their age- and sex-matched clinically healthy controls. Plasma samples from the participants were subjected to in-house enzyme-linked immunosorbent assay (ELISA) to determine their antibody levels.

Results

Using ETBF total protein as coating antigen, 38/39 (97%) CRC cases and 36/39 (92%) controls showed anti-ETBF IgG above cut-off, while all (100%) CRC cases and 36/39 (92%) controls had anti-ETBF IgA levels above cut-off. With culture broth as coating antigen, all (100%) CRC cases and 37/39 (95%) controls had anti-ETBF IgG levels above cut-off. For anti-ETBF IgA, all (100%) cases and controls had levels above cut-off. Statistical analysis reveals no significant difference (P > 0.05) on the number of CRC cases and controls with IgG and IgA antibody levels above cut-off value. Also, there's no significant difference (P > 0.05) in the mean anti-ETBF antibody levels of cases who were at different tumor grade (well differentiated and moderately and poorly differentiated) and tumor stage (early and advanced).

Conclusions

These results suggest that Filipino CRC cases and their clinically healthy matched controls exhibit antibody responses against ETBF.

Strongyloidiasis in humans and dogs in Southern Italy: an observational study

Strongyloidiasis is a clinical issue both in humans and in dogs. Moreover, there are concerns about its zoonotic potential. We aimed to explore Strongyloides stercoralis epidemiology in Southern Italy in humans and dogs sharing the same environment in three different settings: (1) kennels (group K); (2) livestock farms (group L) and (3) agricultural farms (group A). For humans, a commercial ELISA test was used for screening. RT-PCR on faecal samples was done for people testing positive or equivocal at serology. On dog's faecal samples, Baermann test and RT-PCR were performed. A total of 145 dogs and 139 persons were tested. Based on faecal tests in dogs and serology in humans, a S. stercoralis positivity of 4.1% and 6.5% was revealed, respectively. The sites where cases were found were different for animals and humans. In dogs the highest positivity was in group K (6.7% against 2% and 0% in L and A). Differently, in humans the proportion of positive results was similar between the groups (p = 0.883). Fifty percent (3/6) of positive dogs were healthy; the other dogs presented weight loss and/or diarrhoea. ELISA-positive persons (n=9) were all in health, but abdominal pain (37.5%), urticaria (22.2%) and asthma (22.2%) were reported, resolving after treatment with oral ivermectin 200 μg/kg. RT-PCR performed on 13 human faecal samples resulted negative. These findings suggest that strongyloidiasis is present in humans and dogs in Southern Italy, and screening in larger cohorts would be needed for more accurate estimates.

Enhanced monitoring and detection of recent genotype 3 hepatitis E virus infection through urine antigen testing

Hepatitis E virus (HEV) is the leading cause of acute viral hepatitis. Numerous studies have investigated the dynamics of HEV infection markers, but the most suitable marker for diagnosing ongoing or recent HEV infection remains to be determined. Recent evidence suggests that serum antigen testing is superior to serum IgM and RNA quantification. Moreover, it has been found that infected individuals excrete HEV antigen in significant quantities through urine. To address this question, we conducted a longitudinal analysis involving 16 patients with acute or chronic HEV infection in an area where genotype 3 HEV is prevalent. Our findings indicate that the diagnostic and monitoring capabilities of antigen testing for HEV infection can be further enhanced by measuring it in urine. Additionally, we were able to demonstrate that this enhancement is likely due to the presence of HEV-reactive IgG in blood plasma, which hampers efficient detection of HEV antigen through sandwich ELISA. In conclusion, urine-based antigen testing appears to be superior to measuring anti-HEV antibodies or viral RNA for diagnosing suspected HEV infection and monitoring ongoing infections.

Development of a Recombinant Enzyme-Linked Immunosorbent Assay for the Detection of Antibodies Against Infectious Bronchitis Virus

Infectious bronchitis virus (IBV), a gammacoronavirus within the Coronaviridae family, is an economically important etiological disease agent in chickens. Both early diagnosis and determination of the immune status of chickens are important for controlling IBV outbreaks in chicken flocks. The N protein is the most abundantly expressed virus-derived protein during IBV infection and can induce a strong immune response by producing antibodies during early infection or immunization. In this study, we found that the amino acid sequences of the N protein between CK/CH/LJL/04I and the other 22 IBVs were conserved, especially in the 1-160 amino acid region. Based on the sequence similarities, the three recombinant proteins, rN160 (amino acid positions 1-160), rN266 (144-409), and rN409 (1-409), were expressed using the Escherichia coli system and subsequently purified. The results demonstrated that the antigenicity and reactivity of rN160 were better than those of rN266 and rN409. As a result, an indirect enzyme-linked immunosorbent assay (ELISA) (rN160 ELISA) was developed to detect the IBV antibody based on the rN160 protein. Using 1,500 clinical field serum samples, the relative sensitivity, specificity, and accuracy of the rN160 ELISA were 98.97%, 92.34%, and 97.93%, respectively, compared to those of a commercial ELISA kit (IDEXX), indicating a strong positive correlation between the two methods. Taken together, these results reveal that the rN160 ELISA is a rapid, simple, and sensitive method for detecting group-specific IBV antibodies for epidemiological investigation and antibody-level monitoring.

Clinical significance of IL-37 serum level and polymorphism in patients with endometrial cancer

Endometrial cancer (EC) is recognized as the second most common type of cancer among women. Interleukin-37 (IL-37) is a recently discovered member of the IL-1 cytokine family characterized by its anti-inflammatory properties, which are believed to have both anti-tumour and tumorigenic effects. However, the precise role of IL-37 in the development of EC remains largely unknown. In the current study, we aimed to explore genotype and allele frequencies of the IL-37 gene (rs4241122) and measure IL-37 protein levels in patients with EC, with a view to determining the clinical significance in these patients. A total of 105 patients with confirmed EC and 105 healthy controls, aged 31-73, participated in the study. IL-37 serum levels were investigated using an ELISA method, while the frequency of genotypes and alleles of the IL-37 gene was determined using the ARMS-PCR method. The findings demonstrate a significant increase in IL-37 serum levels in EC patients compared to controls (p<0.0001). Moreover, higher levels of IL-37 were strongly associated with unfavourable indices, such as EC grade III, poorly differentiated tumours, and regional spread of tumour cells (p<0.05). However, genotyping of the IL-37 gene revealed no significant difference between the two groups, and there was no association between IL-37 genotype and IL-37 protein level or clinicopathological characteristics (p>0.05). The results of this study suggest that elevated serum levels of may contribute to tumour progression, probably through its immune suppressive activity. Clinically, IL-37 may serve as a promising factor and/or therapeutic target for EC management, although, further studies are warranted.

Quantitative analysis of therapeutic proteins in biological fluids: recent advancement in analytical techniques

Pharmaceutical application of therapeutic proteins has been continuously expanded for the treatment of various diseases. Efficient and reliable bioanalytical methods are essential to expedite the identification and successful clinical development of therapeutic proteins. In particular, selective quantitative assays in a high-throughput format are critical for the pharmacokinetic and pharmacodynamic evaluation of protein drugs and to meet the regulatory requirements for new drug approval. However, the inherent complexity of proteins and many interfering substances presented in biological matrices have a great impact on the specificity, sensitivity, accuracy, and robustness of analytical assays, thereby hindering the quantification of proteins. To overcome these issues, various protein assays and sample preparation methods are currently available in a medium- or high-throughput format. While there is no standard or universal approach suitable for all circumstances, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay often becomes a method of choice for the identification and quantitative analysis of therapeutic proteins in complex biological samples, owing to its high sensitivity, specificity, and throughput. Accordingly, its application as an essential analytical tool is continuously expanded in pharmaceutical R&D processes. Proper sample preparation is also important since clean samples can minimize the interference from co-existing substances and improve the specificity and sensitivity of LC-MS/MS assays. A combination of different methods can be utilized to improve bioanalytical performance and ensure more accurate quantification. This review provides an overview of various protein assays and sample preparation methods, with particular emphasis on quantitative protein analysis by LC-MS/MS.

Validation of low-volume sampling devices for pharmacokinetic analysis: technical and logistical challenges and solutions

While low-volume sampling technologies offer numerous advantages over venipuncture, implementation in clinical trials poses technical and logistical challenges. Bioanalytical methods were validated for measuring the concentration of crenezumab and etrolizumab in dried blood samples collected using Mitra and Tasso-M20. The data generated demonstrate that the concentrations of crenezumab and etrolizumab in dried blood collected by either device could be determined using calibrators prepared in serum. Drug concentrations from dried blood were converted to serum concentrations using patient hematocrit levels. Contract Research Organization experience in sample handling and analysis allowed us to compare differences between various low-volume sampling technologies. This study evaluated challenges and presented potential solutions for use of different low-volume sampling technologies for pharmacokinetic analysis.

Analysis of antibodies avidity for Tityus serrulatus scorpion venom in antivenom production and its potential for application as a potency test

Antivenoms are the only specific medication for neutralizing toxins present in venom of animals such scorpions and snakes through antigen-antibody binding. Several analyses are carried out throughout its production in order to ensure the quality and effectiveness of the antivenom that will be administered to the patient. One of these is the potency assay, which is performed to assess the ability of antivenoms to neutralize the toxic effects of the venom injected in mice. The substitution of in vivo for in vitro assays such as ELISA has been presented by other authors, bringing several advantages such as the reduction in the use of animals, in costs and in the duration of the assays. However, the avidity index of antivenom antibodies determined by ELISA has not yet been applied for this purpose. Therefore, the objective of this study was to evaluate the avidity of sera from hyperimmunized horses with crude Tityus serrulatus venom, a scorpion species associated with the most serious accidents in Brazil, and its potential for application as a potency test replacing the in vivo assay. The avidity ELISA proved to be interesting for monitoring the binding strength of antibodies produced by horses in hyperimmune plasma production programs. It was possible to verify oscillations in antibody avidity that occurred along the immunization cycles, differences between novice and veteran horses, maturation of antibody avidity, and correlation between avidity index and antibody titre. Similar results were obtained for crude venom and purified Ts1 toxin. In addition, the avidity ELISA apparently demonstrated potential for application as a potency test in the initial stage of antivenom production. However, more studies are necessary.

Equine tapeworm (Anoplocephala spp.) infection: evaluation of saliva- and serum-based antibody detection methods and risk factor analysis in Slovak horse populations

A lack of accurate information on the prevalence and distribution of Anoplocephala spp. infections on horse farms has led to insufficient attention to tapeworm control and increasing horse anoplocephaloses in Europe. Our study aimed to examine the occurrence of Anoplocephala spp. infection using coprological, serum- and saliva-based antibody detection methods and to analyze the risk factors associated with tapeworm infection in domestic horses in Slovakia. Fecal, serum, and saliva samples were collected from 427 horses from 31 farms in Slovakia. Additionally, a questionnaire study was conducted to collect information on tapeworm distribution on horse farms and analyze risk factors associated with infection. Fecal samples were examined by the mini-FLOTAC and the double centrifugation/combined sedimentation-flotation techniques. Serum and saliva samples were analyzed by ELISA to determine antibody levels against Anoplocephala spp. The effects of variables associated with an individual horse were tested for the positive result of the saliva ELISA test on Anoplocephala spp. Cestode eggs were detected in 1.99% of fecal samples (farm prevalence 12.90%), with no differences between the two coprological methods. Serum-based tapeworm ELISA results revealed that 39.39% of horses tested positive (farm prevalence 83.87%); while saliva-based tapeworm ELISA results revealed 56.95% positive horses (farm prevalence 96.77%). Binary logistic regression analysis revealed four meaningful predictors that significantly impacted the likelihood of detecting tapeworm infection in horses: horse age, pasture size, anthelmintic treatment scheme, and access to pasture. The influences of other variables associated with an individual horse were not significantly associated with detecting tapeworm infection.

Development and evaluation of mouse anti-Ara h 1 and Ara h 3 IgE monoclonal antibodies for advancing peanut allergy research

Immediate hypersensitivity reactions to peanuts are a considerable public health concern due to the acute and severe IgE mediated reactions. To conduct research on the pathogenesis and therapeutics of peanut allergies, it is imperative to have mouse anti-crude peanut extract (CPE) IgE monoclonal antibodies (mAbs) for both in-vitro and in-vivo assays. Without these tools, it is difficult to advance research in this field. In this study, four hybridomas producing anti-CPE IgE mAbs were developed and the IgE mAbs were validated using immune-blot analysis, Sandwich ELISA, Indirect ELISA, a cell-based assay using RBL-2H3 cells, and footpad type I hypersensitivity reaction studies in mice. The results indicate that two of the four mAbs can be effectively used for both in-vitro and in-vivo peanut allergy studies, as they induce allergic reactions with sensitization alone in mice. These novel anti-Ara h1 and Ara h 3 IgE mAbs, in combination with the detailed protocols outlined in this article, offer valuable guidance for studying acute allergic reactions involving mast cells across various platforms. With some considerations, the IgE mAbs can significantly advance peanut allergy research.

The dynamics of neutralizing antibodies against SARS-CoV-2 in cats naturally exposed to virus reveals an increase in antibody activity after re-infection

Severe Acute Respiratory Syndrome Coronavirus 2 is the causative agent of Coronavirus Disease 2019 in humans. To date, little is known about the persistence of antibodies against SARS-CoV-2 in animals under natural conditions, in particular susceptible pets such as cat. This study reports the detection and monitoring of the humoral response against SARS-CoV-2 including the detection of immunoglobulins G specific for receptor binding domain of SARS-CoV-2 spike protein by an enzyme-linked immunosorbent assay and neutralizing antibodies by virus neutralization assay. Results showed that these antibodies last longer than 16 months in two naturally apparently healthy infected cats with the absence of clinicopathological findings during the follow-up. Moreover, re-infection is also possible with an important increase in virus neutralization test titers in both animals with no evident systemic signs found during each physical examination and with values of hematologic and biochemical parameters inside the normal reference intervals. Our results confirm a slow but progressive decrease of the kinetics and immunity of neutralizing antibodies in cats after the infection. Furthermore, similar to humans SARS-CoV-2 reinfection can stimulate an increase of the neutralizing antibodies determined by these two serological techniques in domestic cats.

Application of a Receptor-Binding-Domain-Based Simple Immunoassay for Assessing Humoral Immunity against Emerging SARS-CoV-2 Virus Variants

We have developed a simple, rapid, high-throughput RBD-based ELISA to assess the humoral immunity against emerging SARS-CoV-2 virus variants. The cDNAs of the His-tagged RBD proteins of the virus variants were stably engineered into HEK cells secreting the protein into the supernatant, and RBD purification was performed by Ni-chromatography and buffer exchange by membrane filtration. The simplified assay uses single dilutions of sera from finger-pricked native blood samples, purified RBD in 96-well plates, and a chromogenic dye for development. The results of this RBD-ELISA were confirmed to correlate with those of a commercial immunoassay measuring antibodies against the Wuhan strain, as well as direct virus neutralization assays assessing the cellular effects of the Wuhan and the Omicron (BA.5) variants. Here, we document the applicability of this ELISA to assess the variant-specific humoral immunity in vaccinated and convalescent patients, as well as to follow the time course of selective vaccination response. This simple and rapid assay, easily modified to detect humoral immunity against emerging SARS-CoV-2 virus variants, may help to assess the level of antiviral protection after vaccination or infection.

Correlation of desmoglein 1 and 3 immunohistochemistry with autoantibody levels and clinical severity in pemphigus

BACKGROUND

Pemphigus is a chronic potentially fatal autoimmune bullous disorder. Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are the two common subtypes. PV is the most common and aggressive type characterized by oral mucosal erosions and cutaneous lesions. PF presents with blisters on the scalp, face, and upper trunk, and spares the mucosae. Direct immunofluorescence (DIF) is the gold standard for diagnosis. Immunohistochemistry (IHC) is an emerging alternate diagnostic tool. In this study, our objectives were to identify the staining patterns of desmoglein 1 (dsg 1) and desmoglein 3 (dsg 3) IHC and to correlate the same with autoantibody levels and clinical severity in patients with PV and PF.

METHODS

Forty-nine clinically, histologically, and DIF-confirmed cases of pemphigus were included in the study. The IHC patterns were scored from 0 to 3+ with 3+ dsg 1 IHC exhibiting intense membranous staining in the upper layers of the epidermis and 3+ dsg 3 IHC showing intense basal layer staining. Enzyme-linked immunosorbent assay (ELISA) for anti-dsg 1 and 3 antibodies was performed in 38 cases where serum samples were available. The pemphigus disease activity index system was utilized for clinical scoring.

RESULTS

A 0 to 1+ score was observed for dsg 1 IHC in 100% of PF cases. A score of 0 to 1+ was observed for dsg 3 IHC in 97.3% of PV cases. One hundred percent of cases with PF and 83.9% of patients with PV tested positive for ELISA anti-dsg 1 and 3 antibody titers, respectively. Anti-dsg 1 and 3 ELISA titers significantly correlated with the dsg 1 and dsg 3 IHC scores. The mucosal scores showed a significant association with both dsg 1 and 3 IHC (p < 0.001). The cutaneous scores showed a significant association with the dsg 3 IHC (p < 0.001).

CONCLUSION

The IHC patterns for dsg 1 and 3 proved reliable in giving concordant results with the ELISA antibody titers and clinical severity.

Human Norovirus Detection: How Much Are We Prepared?

Norovirus (NoV) is known to be the second nonbacterial enteric pathogen after rotavirus that causes acute gastroenteritis. They can be spread from person to person through fecal-oral routes. Infection can lead to severe diarrhea, causing stomach pain, vomiting, and nausea. Rapid detection of NoV can control huge economic and productive losses. Genotyping various emerging NoV strains is important to compare the severity among different strains. Conventional immunological and molecular methods have evolved and contributed to developing detection techniques. Immunological (enzyme-linked immunosorbent assay) and molecular detection (reverse transcriptase polymerase chain reaction [RT-PCR], RT-quantitative PCR, loop-mediated isothermal amplification, nucleic acid sequence-based alignment, recombinase polymerase amplification) methods have been mainly used. The development of biosensors using aptasensor, affinity peptides, nanoparticles, microfluidics, and so on, are currently the most researched topics. The availability of next-generation sequencing technologies has greatly influenced the diagnosis of NoV. The complementation of advanced technologies is helpful in identification of new variants. In this study, techniques that are useful in detecting NoV are discussed. This review has investigated the availability of recent methods used in the detection, present status, and futuristic plan of action in case of outbreak and pandemic.

First serological evidence of MERS-CoV in dromedary camels from Algeria

Middle East Respiratory Syndrome (MERS) is a zoonotic disease. Dromedary camel is responsible of its transmission to humans. Accordingly, several human cases have been reported worldwide with a high mortality rate. In Algeria, no data reported on MERS prevalence in camels. This is a first seroprevalence study MERS-CoV in Algerian dromedaries. A total of 87 camel blood samples from EL -MENIAA and Ghardaia, were analyzed by anti-MERS-CoV IgG ELISA camel. The seroprevalence was 64 % and it significantly increases with age. Larger serological and molecular screening is needed to precisely determine the rate of MERS active circulation among Algerian dromedary population.

Oxidative Stress Enzyme as Markers in Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma Patients

Oxidative stress is a recognized factor that poses a significant risk for the development of Oral Squamous Cell Carcinoma (OSCC) and Oral Submucous Fibrosis (OSMF), as it leads to the generation of Reactive Oxygen Species. In recent years, there has been significant research on the enzymes MDA (malondialdehyde) and SOD (superoxide dismutase), investigating their potential role in the development of OPMD and OSCC. These enzymes have emerged as promising biomarkers due to their ability to provide a less invasive, cost-effective, and objective diagnostic method. Furthermore, they can be used to monitor disease progression and assess the effectiveness of therapy. The aim of this study was to assess the levels of MDA and SOD in the serum of patients diagnosed with OSCC and OSMF. Study group comprised of 60 patients, out of which 20 cases of clinically diagnosed OSCC patients and 20 cases of OSMF and 20 cases pf control comprising of healthy patients were recruited. Estimation MDA and SOD was done by ELISA. The statistical analysis was done using SPSS analysis. When comparing the levels of MDA and SOD between the OSCC and OSMF groups and the control group, statistically significant findings indicated elevated levels of malondialdehyde and reduced levels of superoxide dismutase in both the OSCC and OSMF groups. In this study, the assessment of lipid peroxidation through MDA levels revealed elevated concentrations in both the OSCC and OSMF groups when compared to the control group. Specifically, the order of MDA levels was observed as OSCC > OSMF > Control. Conversely, antioxidant enzyme levels, such as SOD, exhibited decreased concentrations in the OSCC and OSMF groups compared to the control group, with the order of SOD levels being Control > OSMF > OSCC. Consequently, the findings suggest that MDA and SOD can be considered potential biomarkers for identifying and monitoring OSCC and OSMF diseases.

Unraveling swine hepatitis E in the central region of Argentina through ELISA development and epidemiological insights

Hepatitis E virus (HEV) is a public health concern globally, causing acute viral hepatitis in humans. Genotype-3 HEV (HEV-3), the most frequently genotype detected in South America, is zoonotic and the main reservoirs are the domestic pig and wild boar. Circulation of HEV-3 in Argentina has been confirmed in humans as well as in pig herds, wild boar and environmental waters. However, data are scarce mainly due to the inaccessibility of serological assays in this country. In order to provide insights in the epidemiology of HEV in swine in Argentina, we developed an indirect ELISA based on the native recombinant protein ORF2 and conducted a serological survey to determine the prevalence of seropositive swine in small-scale pig farms in the central region of Argentina. The method was evaluated in a panel of 157 serum samples, resulting in relative sensitivity of 98.6 % (95 % CI 95 %-100 %) and relative specificity of 97.7 % (95 % CI 94 %-100 %) compared to a commercial test. An almost perfect agreement was obtained between the two tests (Kappa index of 0.961). A survey on 294 samples from 49 small-scale farms resulted in a seropositivity rate of 54 %. Seropositive animals were found in 34 out of 49 (69.4 %) farms. Most of the farms (70.6 %) had over 50 % of seropositive animals. The wide spreading of HEV in the swine population of Tandil, Argentina, underscore the need to better understand the epidemiology of HEV in the region, enabling the implementation of targeted interventions to mitigate the impact of this virus on public health.

Characterization of a Lipopolysaccharide- and Beta-1,3-Glucan Binding Protein (LGBP) from the Hepatopancreas of Freshwater Prawn, Macrobrachium rosenbergii, Possessing Lectin-Like Activity

The study focuses on the isolation, characterization, and expression analysis of a lectin from the hepatopancreas of Macrobrachium rosenbergii. The protein was isolated by affinity chromatography on a melibiose-agarose column. The molecular weight of the native protein was found to be ~120 kDa which consists of a single polypeptide of ~39.5 kDa. On mass spectrometric analysis, the protein was identified as lipopolysaccharide- and beta-1,3-glucan binding protein (LGBP). LGBP showed hemagglutination with rabbit RBC like a lectin and its carbohydrate-binding specificity was determined by the hemagglutination inhibition test. The protein also showed antibacterial activity against two Gram-negative bacteria Vibrio harveyi and Aeromonas sobria, and one Gram positive bacteria Bacillus cereus in the disc diffusion test. Rabbit antiserum was raised against the purified LGBP and used to develop a sandwich ELISA system for quantitation of the protein in hepatopancreas and serum samples of M. rosenbergii. The expression of the LGBP transcripts in muscle, hepatopancreas, and gill tissues from M. rosenbergii juveniles at 72 h post-challenge of V. harveyi was not modulated as noticed in qPCR analysis. However, significant increases in the concentrations of LGBP protein in hepatopancreas (5.23 ± 0.45 against 3.43 ± 0.43 mg/g tissue in control) and serum (1.08 ± 0.14 against 0.61 ± 0.08 µg/ml in control) were observed in the challenged group of prawns in ELISA suggesting its putative role against bacterial infections. The study for the first time characterized the native LGBP of M. rosenbergii showing a multifunctional role in immunity.

The effect of non-surgical periodontal therapy on salivary IL-6 levels in patients with moderate to severe generalized chronic periodontitis

BACKGROUND

Gene regulation of IL-6 is characterized by the presence of inflammatory cytokines, bacterial products, viral infection, and activation of the diacylglycerol-, cyclic AMP-, or Ca + + -activated signal transduction pathways.

AIM

Scaling and root planning (SRP), a non-surgical periodontal therapy, was studied in connection to several clinical parameters for its effect on salivary IL-6 levels in patients with generalized chronic periodontitis.

METHODS

For this study, a total of 60 GCP patients were included. Plaque index (PI), gingival index (GI), pocket probing depth (PPD), bleeding on probing percentage (BOP%), and clinical attachment loss were among the clinical indicators covered (CAL).

RESULTS

Following SRP, mean IL-6 levels in patients with GCP were significantly higher in the pre-treatment group (2.93 5.17 pg/ml; p 0.05) than in the posttreatment group (5.78 8.26 pg/ml; baseline). Pre- and post-treatment IL-6 levels for PI (pre), BOP percent (pre/post), GI (post), and PPD were found to be positively correlated (post). In patients with GCP, the study showed a statistically significant correlation between periodontal metrics and salivary IL-6.

CONCLUSIONS

Changes in periodontal indices and IL-6 levels that are statistically significant over time indicate that non-surgical treatment is effective, and IL-6 can be regarded as a potent disease activity marker.

Antibody avidity to pertussis toxin after acellular pertussis vaccination and infection

Pertussis toxin (PT) is a unique virulence factor of Bordetella pertussis, and therefore a key component of acellular pertussis vaccines. Although immunity after infection seems to persist longer than after vaccination, the exact mechanisms are not fully known. In this study the overall binding strength (avidity) of anti-PT IgG antibodies was compared after acellular booster vaccination and infection, as a parameter to evaluate long-lasting protection.Danish and Finnish serum samples from a total of 134 serologically confirmed patients and 112 children who received acellular booster vaccines were included in this study. The concentration of anti-PT IgG was first determined by ELISA, followed by two separate ELISAs to evaluate antibody avidity: either with a dilution series of urea as a bond-breaking agent of antibody and antigen binding and a constant anti-PT IgG concentration between the samples or with a constant dilution ratio of sera and detergent. In addition to urea, the use of diethylamine and ammonium thiocyanate as disruptive agents were first compared between each other.A strong Spearman correlation (R > 0.801) was noted between avidity and concentration of anti-PT IgG antibodies if a constant serum dilution method was used, and avidity was noted to be higher in patients in comparison to vaccinees in Denmark, but not in Finland. However, no correlation between antibody concentration and avidity was found if a constant anti-PT IgG concentration was used (R = -0.157). With this method, avidity after vaccination was significantly higher in comparison to that after infection in both Danish and Finnish subjects (p < 0.01). A shorter time since the latest booster vaccination was found to affect avidity positively on the next PT-antigen exposure with either vaccination or infection.

Prevalence of COVID-19 antibodies in employees of St. Jacob Hospital in Bardejov

OBJECTIVE

The COVID-19 disease caused by the SARS-CoV-2 virus belongs to the group of highly infectious diseases with increased mortality and morbidity in the population. Finding the presence of antibodies plays an important role while finding the number of individuals who overcame the disease or were vaccinated.

METHODS

A total of 250 employees of St. Jacob Hospital with Polyclinic, Bardejov, participated in our study, the blood samples were drawn from the index finger and processed with the help of the rapid Ag test for the detection of antibodies and venous blood using the ELISA method. The health workers (doctors, nurses, medical laboratory technicians, laboratory diagnosticians) tested during September and October 2022 participated in our study.

RESULTS

Our experimental study shows the presence of IgG antibodies in 215 (86%) of employees, who get them from overcoming the COVID-19 disease or getting vaccinated. In 17 (6.8%) of employees were detected IgG and IgM antibodies. The biggest number of IgG antibodies was found in 36 (78%) employees of the Surgical Department, 28 (84%) employees of Rehabilitation Department and 25 (89%) employees of the Internal Department, when compared with the Department of Laboratory Medicine 9 (30%) employees and Radiology Department 4 (44%) employees.

CONCLUSION

Multiple prevalence of COVID-19 disease were found in employees of the internal, surgical and rehabilitation departments in whom we detected a higher presence of IgG antibodies. In department of laboratory medicine workers were proven lower levels of IgG antibodies, mainly for the limited contact with the positive covid patients and working with only their biological material, compared to the first-line employees exposed to direct contact with the patients.

A costing framework to compare tuberculosis infection tests

OBJECTIVE

To develop a framework to estimate the practical costs incurred from, and programmatic impact related to, tuberculosis (TB) infection testing-tuberculin skin tests (TST) versus interferon gamma release assay (IGRA)-in a densely populated high-burden TB area.

METHODS

We developed a seven-step framework that can be tailored to individual TB programmes seeking to compare TB infection (TBI) diagnostics to inform decision-making. We present methodology to estimate (1) the prevalence of TBI, (2) true and false positives and negatives for each test, (3) the cost of test administration, (4) the cost of false negatives, (5) the cost of treating all that test positive, (6) the per-test cost incurred due to treatment and misdiagnosis and (7) the threshold at which laboratory infrastructure investments for IGRA are outweighed by system-wide savings incurred due to IGRA utilisation. We then applied this framework in a densely populated, peri-urban district in Lima, Peru with high rates of Bacillus Calmette-Guérin (BCG) vaccination.

FINDINGS

The lower sensitivity of TST compared with IGRA is a major cost driver, leading to health system and societal costs due to misdiagnosis. Additionally, patient and staff productivity costs were greater for TST because it requires two patient visits compared with only one for IGRA testing. When the framework was applied to the Lima setting, we estimate that IGRA-associated benefits outweigh infrastructural costs after performing 672 tests.

CONCLUSIONS

Given global shortages of TST and concerns about costs of IGRA testing and laboratory capacity building, this costing framework can provide public health officials and TB programmes guidance for decision-making about TBI testing locally. This framework was designed to be adaptable for use in different settings with available data. Diagnostics that increase accuracy or mitigate time to treatment should be thought of as an investment instead of an expenditure.

Comparison of diagnostic methods for assessment of Ostertagia ostertagi exposure in Norwegian dairy herds

BACKGROUND

The gastrointestinal nematode (GIN) Ostertagia ostertagi can cause severe disease in first season grazers (FSG) and impaired performance due to subclinical infections in adult cows. Diagnostic methods to assess exposure include faecal egg count and detection of specific antibodies using antibody-ELISAs resulting in an optical density ratio (ODR). Using the ELISA test on bulk tank milk (BTM) allows for a herd level diagnosis. Appropriate use of diagnostic methods for evaluation of O. ostertagi exposure is required to optimize herd parasite surveillance and aid in a sustainable control regime. The aim of this study was to describe the relationship between different diagnostic tests used to assess GIN exposure in Norwegian production systems. A cross-sectional field study was carried out in twenty herds in Norway in the fall of 2020. Serum and faecal samples were taken from 380 individuals, of which 181 were FSG and 199 were cows. In addition, milk was collected from every cow and one BTM sample was taken from each herd. Faecal egg counts were performed. The distribution of ODR values in individual samples within and between herds and the associations between BTM ODR and individual ODR values were described. The data were analysed using visual assessment of scatter plots, Pearson correlation coefficients and linear regression.

RESULTS

A high variability of the within-herd individual ODR values in serum and milk in every herd was detected. The ODR in BTM explained a low degree of the variation in the individual serum and milk samples. When plotting the ODR results in milk or serum according to four BTM categories, the distribution of ODR values were notably different in the highest and lowest BTM categories. The correlation between individual milk and serum samples was moderate (r = 0.68), while the highest correlation (r = 0.81) was between the BTM ODR and the group average individual milk samples.

CONCLUSIONS

A poor predictive ability for BTM ODR to assess individual ODR values in both FSG and cows was demonstrated. However, the study indicates that the evaluation by ELISA test on BTM to assess exposure to GIN could be useful in herds with a very high or low BTM ODR.

Seroprevalence of Toxoplasma gondii, Neospora caninum and Trichinella spp. in Pigs from Cairo, Egypt

Pork production is a niche economy in Egypt, and pigs are typically raised as backyard animals with no sanitary control, potentially exposing them to various pathogens. Commercially available ELISAs were used to detect specific antibodies to the food-borne zoonotic parasites Toxoplasma gondii and Trichinella spp., as well as to Neospora caninum, in serum samples of pigs slaughtered at Egypt's only licensed pig abattoir, the El-Bassatin abattoir in Cairo. Among the tested sera (n = 332), seroreactivity for T. gondii was 45.8% (95% confidence interval: 40.4-51.3), N. caninum was 28.0% (95% CI: 23.3-33.2), and Trichinella spp. was 1.2% (95% CI: 0.4-3.3). Mixed infection was only detected for T. gondii and N. caninum (18.7%; 95% CI: 14.7-23.4). The seroprevalence of T. gondii was significantly higher (p = 0.0003) in animals collected from southern Cairo (15 May city slum) than in eastern Cairo (Ezbet El Nakhl slum). Seroprevalence for N. caninum was higher in western (Manshiyat Naser slum; p = 0.0003) and southern Cairo (15 May city slum; p = 0.0003) than in that of eastern Cairo (Ezbet El Nakhl slum; p = 0.0003). Moreover, female pigs exhibited a higher rate of N. caninum antibodies than male ones (p < 0.0001). This study provides the first seroprevalence data for N. caninum in pigs in Egypt, and updates the prevalence of the zoonotic parasites Trichinella spp. and T. gondii.

Estimation of postmortem interval using histological and oxidative biomarkers in human bone marrow

In forensic medicine, estimating the postmortem interval (PMI) is of great importance for the timeline and the reconstruction of the events surrounding death. Bone marrow (BM) is one of the largest organs in the body, with good resistance to autolysis and contamination. Therefore, the present study aims to correlate different postmortem intervals and bone marrow antioxidant enzyme levels using an Enzyme-linked immunosorbent assay (ELISA). In addition, detection of the changes in the histological structure of human bone marrow in relation to the time passed since death. BM samples from 20 forensic autopsy cadavers were obtained from cases referred to the Department of Forensic Medicine in the Ministry of Justice, Dakahlia Governorate, processed for histopathological examination as well as estimation of reduced glutathione (GSH), glutathione peroxidase (GPX), and glutathione reductase (GRX) using ELISA. Results of ELISA analysis showed a significant decrease in the level of antioxidant enzymes with increasing PMI; regarding histopathological examination, from 6 to > 18 h PMI, the changes in morphology after death were gradual, progressive, and regular, indicating great value in PMI determination. Also, 18 h of PMI showed loss of cellular details, absence of fat cells, and necrosis of BM with the nucleus dispersed as eosinophilic debris. Estimation of antioxidant enzymes level in human bone marrow using ELISA and detection of the changes in the histological structure of human bone marrow in relation to time passed since the death, either separately or in combination, can be used to estimate PMI accurately.

Seroprevalence and risk factors of Streptococcus ovis infection in Tibet, China

Sheep septicemic streptococcosis is an acute, febrile, and septic zoonotic disease caused by Streptococcus ovis. There are few reports of this disease especailly at high-altitude areas of Tibet, China. A cross-sectional study was conducted at five different counties of Shigatse area (a city in Tibet territory) from 2021 to 2022. Sera from 1458 randomly selected sheep and goats from 50 flocks were tested for antigens of Streptococcus ovis using a commercial ELISA kit. The individual animal level prevalence was 6.93% (95% CI: 5.7-8.4), and the flock prevalence level was 84% (95% CI: 70.9-92.8). At the individual animal level, year and management type were significantly associated with seropositivity by binary logistic regression analysis. Prevalence of Streptococcus in 2021 significantly differed from 2022 (OR = 2.16, 95% CI: 1.39-3.39). The prevalence of Streptococcus varied between management types with herds having higher odds of disease than intensive farms (OR = 2.64, 95% CI: 1.71-4.10). Hence, our study reports for the first time on seroepidemiology and risk factors of Streptococcus ovis infection, laying a theoretical foundation for preventing and controlling streptococcosis in Tibet area.

TSH Pulses Finely Tune Thyroid Hormone Release and TSH Receptor Transduction

Detection of circulating TSH is a first-line test of thyroid dysfunction, a major health problem (affecting about 5% of the population) that, if untreated, can lead to a significant deterioration of quality of life and adverse effects on multiple organ systems. Human TSH levels display both pulsatile and (nonpulsatile) basal TSH secretion patterns; however, the importance of these in regulating thyroid function and their decoding by the thyroid is unknown. Here, we developed a novel ultra-sensitive ELISA that allows precise detection of TSH secretion patterns with minute resolution in mouse models of health and disease. We characterized the patterns of ultradian TSH pulses in healthy, freely behaving mice over the day-night cycle. Challenge of the thyroid axis with primary hypothyroidism because of iodine deficiency, a major cause of thyroid dysfunction worldwide, results in alterations of TSH pulsatility. Induction in mouse models of sequential TSH pulses that mimic ultradian TSH profiles in periods of minutes were more efficient than sustained rises in basal TSH levels at increasing both thyroid follicle cAMP levels, as monitored with a genetically encoded cAMP sensor, and circulating thyroid hormone. Hence, this mouse TSH assay provides a powerful tool to decipher how ultradian TSH pulses encode thyroid outcomes and to uncover hidden parameters in the TSH-thyroid hormone set-point in health and disease.

Concentration of Secreted Frizzled-Related Proteins (SFRPs) in Non-Small Cell Lung Carcinoma Subtypes-A Preliminary Study

Non-small cell lung carcinoma (NSCLC) is the most common lung cancer worldwide. Secreted frizzled-related proteins (SFRPs) are important tumour suppressors and antagonists of the Wnt signalling pathway, which is linked with cancer development. The aim of this study was to evaluate the concentrations of SFRP1, SFRP2, and SFRP5 proteins in tumour and non-tumour (NT) samples obtained from 65 patients with primary NSCLC. An enzyme-linked immunosorbent assay (ELISA) was used to measure the concentrations of SFRPs in the tissue homogenates. A significantly lower SFRP2 protein concentration was found in the total NSCLC tumour samples and the following NSCLC subtypes: squamous cell carcinoma (SCC) and adenocarcinoma (AC) (p > 0.05, p = 0.028 and p = 0.001, respectively). AC tumour samples had a higher SFRP1 level than NT samples (p = 0.022), while the highest SFRP1 concentration was found in NSCLC samples from patients with clinical stage T4 cancer. Increased concentrations of SFRP1 and SFRP5 were present in stage III NSCLC samples, while the tumour samples with high pleural invasion (PL2) had an increased level of SFRP2. The results from this study suggest that the tumour suppressor or oncogenic roles of SFRPs could be connected with the NSCLC subtype. The levels of SFRPs varied according to the clinicopathological parameters of NSCLC.

In-house ELISA protocols for capsid p24 detection of diverse HIV isolates

BACKGROUND

The capsid p24 (CA-p24) antigen is a component of the viral capsid of human immunodeficiency virus (HIV) that has been commonly used for clinical diagnosis and monitoring of HIV infections in Enzyme-linked Immunosorbent Assays (ELISAs). Commercial CA-p24 ELISAs are widely used in research settings, but these kits are costly and have limited breadth for detecting diverse HIV isolates.

METHODS

Commercial CA-p24 antibodies were used as capture and detection antibodies. Specific CA-p24 ELISAs were established with these antibodies and tested for the detection of HIV-1 isolates with the aim of developing in-house protocols to recognize HIV-1 infections in vitro for research purposes.

RESULTS

Here we present four protocols for in-house ELISAs to detect HIV CA-p24 using commercial antibodies. The assays were able to detect the CA-p24 antigen of different HIV-1 isolates tested. Comparison between the protocols showed that these in-house ELISAs exhibit high specificity, sensitivity, and reproducibility for CA-p24 quantitation but their reactivity varied per HIV-1 isolate and subtype.

CONCLUSIONS

These optimized ELISA protocols represent valuable tools to investigate HIV-1 infections in research facilities at a lower price than commercial CA-p24 kits.

The Detection of SARS-CoV-2 Antibodies in an Exposed Human Population Is Biased by the Immunoassay Used: Implications in Serosurveillance

The presence of SARS-CoV-2 antibodies was examined over 7 months in a population of essential service workers exposed during the first epidemic wave in Madrid (Spain). Results obtained with different serological assays were compared. Firstly, serum samples obtained in April 2020 were analyzed using eleven SARS-CoV-2 antibody detection methods, including seven ELISAs, two CLIAs and two LFAs. While all of the ELISA tests and the Roche eCLIA method showed good performance, it was poorer for the Abbott CLIA and LFA tests. Sera from 115 workers with serologically positive results in April were collected 2 and 7 months after the first sampling and were analyzed using five of the tests previously assessed. The results showed that while some ELISA tests consistently detected the presence of anti-SARS-CoV-2 antibodies even 7 months after first detection, other methods, such as the Abbott CLIA test, showed an important reduction in sensitivity for these mature antibodies. The sensitivity increased after establishing new cut-off values, calculated taking into account both recent and old infections, suggesting that an adjustment of assay parameters may improve the detection of individuals exposed to the infection.

A Robust Quadruple Protein-Based Indirect ELISA for Detection of Antibodies to African Swine Fever Virus in Pigs

African swine fever (ASF) emerged in domestic pigs and wild boars in China in 2018 and rapidly spread to neighboring Asian countries. Currently, no effective vaccine or diagnostic tests are available to prevent its spread. We developed a robust quadruple recombinant-protein-based indirect enzyme-linked immunosorbent assay (QrP-iELISA) using four antigenic proteins (CD2v, CAP80, p54, and p22) to detect ASF virus (ASFV) antibodies and compared it with a commercial kit (IDvet) using ASFV-positive and -negative serum samples. The maximum positive/negative value was 24.033 at a single antigen concentration of 0.25 μg/mL and quadruple ASFV antigen combination of 1 μg/mL at a 1:100 serum dilution. Among 70 ASFV-positive samples, 65, 67, 65, 70, 70, and 14 were positive above the cut-offs of 0.121, 0.121, 0.183, 0.065, 0.201, and 0.122, for CD2v, CAP80, p54, p22-iELISA, QrP-iELISA, and IDvet, respectively, with sensitivities of 92.9%, 95.7%, 92.9%, 100%, 100%, and 20%, respectively, all with 100% specificity. The antibody responses in QrP-iELISA and IDvet were similar in pigs infected with ASFV I. QrP-iELISA was more sensitive than IDvet for early antibody detection in pigs infected with ASFV II. These data provide a foundation for developing advanced ASF antibody detection kits critical for ASF surveillance and control.

Development of a Multispecies Double-Antigen Sandwich ELISA Using N and RBD Proteins to Detect Antibodies against SARS-CoV-2

SARS-CoV-2 infects humans and a broad spectrum of animal species, such as pets, zoo animals, and nondomestic animals. Monitoring infection in animals is important in terms of the risk of interspecies transmission and the emergence of new viral variants. Economical, fast, efficient, and sensitive diagnostic tests are needed to analyze animal infection. Double-antigen sandwich ELISA has the advantage of being multispecies and can be used for detecting infections caused by pathogens that infect several animal hosts. This study aimed to develop a double-antigen sandwich ELISA using two SARS-CoV-2 proteins, N and RBD. We compared its performance, when using these proteins separately, with an indirect ELISA and with a surrogate virus neutralization test. Positive and negative controls from a cat population (n = 31) were evaluated to compare all of the tests. After confirming that double-antigen sandwich ELISA with both RBD and N proteins had the best performance (AUC= 88%), the cutoff was adjusted using positive and negative samples from cats, humans (n = 32) and guinea pigs (n = 3). The use of samples from tigers (n = 2) and rats (n = 51) showed good agreement with the results previously obtained using the microneutralization test. Additionally, a cohort of samples from dogs with unknown infection status was evaluated. These results show that using two SARS-CoV-2 proteins in the double-antigen sandwich ELISA increases its performance and turns it into a valuable assay with which to monitor previous infection caused by SARS-CoV-2 in different animal species.

Enhancing Therapeutic Drug Monitoring in Inflammatory Bowel Disease: A Comparative Analysis of Rapid Point-of-Care Infliximab, Adalimumab and Anti-Drug Antibodies' Determination against ELISA

The introduction of point-of-care (POC) assays into clinical practice in patients with inflammatory disease enables on-demand therapeutic decision making. The aim of this study was to compare the POC test Quantum blue (Bühlmann Laboratories) for infliximab (IFX), adalimumab (ADL), and its anti-drug antibodies with the traditional ELISA assay (Promonitor). A total of 200 serum samples were analyzed. Samples were classified into the following three different groups; sub-therapeutic range (IFX < 3 μg/mL and ADL < 5 μg/mL); therapeutic range (IFX: 3-7 μg/mL and ADL: 5-12 μg/mL) and supra-therapeutic range (IFX levels > 7 μg/mL and ADL levels > 12 μg/mL). Significant higher values were measured using the POC test (p < 0.001) for IFX results but no differences in ADL trough levels were observed (p = 0.3101). Spearman's correlation indicated a good correlation between the two assays (rs = 0.88 for ADL and rs = 0.93 for IFX), and McNemar's test revealed significant differences (p = 0.016) when classifying IFX samples between therapeutic and supra-therapeutic ranges but no significant differences were found among the other ranges for either IFX or ADL. These results show that we should be cautious when using these rapid measurement methods, and new targets should probably be defined for IFX when using this new analytical method.

Exploring the mRNA and Plasma Protein Levels of BDNF, NT4, SIRT1, HSP27, and HSP70 in Multiple Sclerosis Patients and Healthy Controls

Multiple sclerosis (MS) is a chronic, autoimmune neurodegenerative disease affecting the central nervous system. It is a major cause of non-traumatic neurological disability among young adults in North America and Europe. This study focuses on neuroprotective genes (BDNF, NT4/5, SIRT1, HSP70, and HSP27). Gene expression and protein levels of these markers were compared between MS patients and healthy controls. Blood samples were collected from 42 patients with multiple sclerosis (MS) and 48 control subjects without MS. Quantitative real-time PCR was performed to measure the expression of specific genes. The samples were analyzed in duplicate, and the abundance of mRNA was quantified using the 2-ΔCt method. ELISA assay was used to measure the concentration of specific proteins in the plasma samples. The results show that a 3.5-fold decrease in the gene expression of BDNF corresponds to a 1.5-fold downregulation in the associated plasma protein concentration (p < 0.001). Similar trends were observed with NT-4 (five-fold decrease, slight elevation in protein), SIRT1 (two-fold decrease, two-fold protein decrease), HSP70 (four-fold increase, nearly two-fold protein increase), and HSP27 (four-fold increase, two-fold protein increase) (p < 0.001). This study reveals strong correlations between gene expression and protein concentration in MS patients, emphasizing the relevance of these neuroprotective markers in the disease.