Antibodies In Serum Samples Research Articles

Cancer-testis antigen ACRBP expression and serum immunoreactivity in ovarian cancer: Its association with prognosis.

IntroductionCancer testis (CT) antigens are attractive targets for cancer immunotherapy because of their expression restriction and immunogenicity. The acrosin binding protein (ACRBP) is a member of CT antigens. This study aimed to evaluate ACRBP expression and immunogenicity in ovarian cancer (OC).MethodsThe expression level of ACRBP in OC tissues, normal ovarian tissues, and cell lines was detected via quantitative real‐time polymerase chain reaction (qRT‐PCR) and immunohistochemistry. We determined the levels of ACRBP antigen and antibody in serum samples collected from patients with OC and healthy donors using enzyme‐linked immunosorbent assays (ELISA), the level of ACRBP in cell‐cultured medium was also tested.ResultsACRBP mRNA and protein expressions were upregulated in OC tissues relative to normal tissue, especially highly expressed in epithelial ovarian cancer (EOC). Moreover, ACRBP expression was significantly correlated with International Federation of Gynecology and Obstetrics (FIGO) stage and chemosensitivity. Serological analysis showed that anti‐ACRBP antibody was detected in the sera of 16 of the 56 (28.5%) patients with OC but not in healthy donors. The area under the receiver operating characteristic curve for ACRBP antibody was 0.802 (95% confidence interval [CI]: 0.708–0.876), and the sensitivity and specificity for ACRBP antibody was 85.71% and 55.0%, respectively. Kaplan–Meier analysis revealed that the overall survival (OS) and disease‐free survival (DFS) in OC patients with high ACRBP expression were significantly lower than those with low expression (p = 0.040, p = 0.021). However, ACRBP antibody level was not associated with prognosis.ConclusionACRBP expression was upregulated in OC tissues and induced humoral immune response in patients with OC, suggesting that ACRBP is a potential prognostic biomarker and a target of tumor immunotherapy for OC.

P-117 LOW PREVALENCE OF HEPATITIS B AND C AMONG PEOPLE LIVING IN POVERTY IN NORTHEAST BRAZIL

Hepatitis B and C infection are responsible for more than 300 million of chronic liver disease patients all over the world. One goal of WHO 2030 agenda is the eradication of hepatitis B and C. However poverty is a great obstacle to achieve this goal. In Brazil, more than 13 million of people live in poverty (PLP) and could be vulnerable to HBV and HCV. This study aims to determine HBV and HCV prevalence and analyze the response to HBV vaccination by measuring anti -HBs antibodies in serum samples from PLP. This was a cross­ sectional study carried out in rural settlement in the municipality of Sao Joao do Piaui, Northeast Brazil in March and July 2019. Participants were recruited in their homes and after signing the informed consent, they gave blood samples. A commercial ELISA was use d for measurements of antibodies against i) hepatitis B surface antigen (anti-HBs) and ii) hepatitis B core antigen (HBc) and of the hepatitis surf ace antigen (HBsAg). Nearly half of the population was female (51.0%). The mean age was 36.2±20.4 years, and about 43.2% received a monthly income of approximately $35.00 USD. Most are self­declared black or mixed race (81.9%), were married (50.1%), 15.5% was illiterate and 25.8% had a maximum of six years of formal schooling. Overall zero positivity for HBsAg, anti-HBc and anti -HBs determined by ELISA was 0.2%, 5.1 % and 43.9%, respectively. Anti-HBs reactivity was not associated with monthly income and schooling. Low rates of vaccination against hepatitis B were found among PLP in Northeast Brazil, highlighting the need for preventive actions towards this population segment, vulnerable and a potential disseminator of this infection. Strategies to increase HBV vaccination will be essential to eradicate hepatitis Band achieve the goals of WHO 2030 agenda. Report the levels of biochemical markers in CLD patients with or without COVID-19 to give more information that could help clinical monitoring. Study was approved by Brazilian Ethics Committee. Blood samples were collected after signed informed consent. Most of individuals were male 56% (37/66) and mean age of population was 49±17 years. Six out 66 CLD patients were SARS CoV-2 RNA positive at baseline. At the end of follow-up, all of these 6 patients achieved SARS-CoV-2 clearance. At least once during follow-up, the CLD group versus CLD/COVID-19 group, 48% (29/60) vs. 17% (1/6) (P = 0.2) had abnormal alanine aminotransferase; 47% (28/60) vs. 17% (1/6) had abnormal aspartate aminotransferase (P = 0.21); 60% (36/60) vs. 67% (4/6) had abnormal γ-glutamyl transferase (P = 1.00), 32% CLD patients (19/60) had abnormal total bilirubin levels vs. none of the CLD/COVID-19 group (P = 0.17). Previous liver disease did not seem to increase the biochemical levels, except GGT, during COVID-19 infection. However, liver function monitoring is still essential for both COVID-19 patients with and without liver disease.

PREVALENCE OF MEASLES IGG ANTIBODIES AMONG HEALTHCARE WORKERS IN BULGARIA

Background: Healthcare workers are at greater risk of acquiring measles than the general population. Transmission occurs from infected patients to staff and from infected staff to patients and colleagues. In inpatient and outpatient settings, susceptible patients suffering from other conditions, especially the elderly and severely ill patients in intensive care units are at a high risk of severe disease or death if infected with measles. The most effective preventive measure against measles is vaccination with two doses of a measles-containing vaccine. Aim: To perform a serological assessment of the presence of measles IgG antibodies among healthcare workers. Materials and Methods: The present study involves serological testing performed on samples from persons working in hospitals and Regional Health Inspectorates in the country. Screening started in connection with a reported measles outbreak in Bulgaria in 2019, and continued into early 2020. An indirect ELISA assay for the detection of specific measles IgG antibodies in serum samples was used. Results: The tested 152 healthcare workers were from 5 regions of the country, i.e. Sofia-capital (n=87), Burgas (n=6), Blagoevgrad (n=5), Dobrich (n=8) and Pazardzhik (n=46). Anti-measles IgG antibodies were detected in 85.5% of the participants (130/152). Negative results, indicating a possible lack of protective immunity against measles, were obtained primarily in samples from persons younger than 40 years of age. Conclusion: Screening to identify healthcare workers who lack presumptive evidence of protective immunity against measles should be reinforced, especially among younger healthcare workers, in order to minimize the risk of measles both among healthcare workers and among patients.

Serum p53 antibodies detection in oral squamous cell carcinoma, oral potentially malignant disorders and healthy individuals: A multicentre study.

To detect antibodies against p53 in serum of patients of oral squamous cell carcinoma and oral potentially malignant disorders compared to healthy individuals. The descriptive cross-sectional study was conducted at the departments of Oral and Maxillofacial Surgery, Peshawar Dental College, Peshawar, Khyber College of Dentistry, Peshawar, and the Pakistan Institute of Medical Sciences, Islamabad, Pakistan, from April, 2016 to March, 2017, and comprised serum of oral squamous cell carcinoma patients in group A, oral potentially malignant disorder patients in group B and healthy individuals in group C. Serum concentrations of anti-p53 antibodies were determined by enzyme-linked immunosorbent assay. Data was analysed using SPSS 20. Of the180 subjects, there were 60(33.3%) in each of the three groups. Circulating serum p53 antibodies were detected in 59(98.3%) cases in group A, 58(96.6%) in group B and in 20(33.3%) individuals in group C (p=0.001). The expression of circulating p53 antibodies in serum samples of squamous cell carcinoma and oral potentially malignant disorders patients indicates the potential to be a probable candidate for being taken as a diagnostic or prognostic biomarker.

Adjuvant effects of bacterium-like particles in the intranasal vaccination of chickens against Newcastle disease

Given that the respiratory mucosa is an important site for the initial replication of Newcastle disease virus (NDV), developing intranasal vaccines for chickens is an effective strategy to protect against this disease. The low immunogenicity of inactivated NDV administered by the mucosal route motivated us to identify a safe and potent adjuvant. Previous studies have shown that bacterium-like particles (BLPs), which serve as mucosal adjuvants, induce effective local and systemic immune responses through TLR2 signaling in both mammals and humans. Here, we report that BLPs could activate the innate immune system of chickens in a manner that was dependent on the combination of chicken TLR2 type 1 (chTLR2t1) and chicken TLR1 type 1 (chTLR1t1). The chicken macrophage-like HD11 cell line was stimulated with BLPs, resulting in the production of nitric oxide and the expression of the proinflammatory cytokines IFN-γ, IL-1β and IL-6. Chickens intranasally immunized with inactivated NDV vaccines mixed with BLP adjuvants exhibited significantly increased levels of local SIgA in their tracheal lavage fluid and as well as hemagglutination-inhibiting antibodies in serum samples. The strong systemic and local immune responses induced by BLP-adjuvanted vaccines provided 100 % protection against intranasal challenge with a lethal dose of virulent NDV without showing any signs of disease. These results indicate that BLPs should be considered for use as a potential mucosal adjuvant for inactivated NDV vaccines and other vaccines for poultry.

Re-isolation of Wuxiang Virus from Wild Sandflies Collected from Yangquan County, China.

We previously isolated a new species of the genus Phlebovirus from wild sandflies collected from Wuxiang County in central China, which named the Wuxiang virus (WUXV). In this study, we re-isolated the WUXV from wild sandflies collected from two villages in Yangquan County, China in 2019. Four virus isolates that caused cytopathic effects in BHK-21 cells were successfully isolated from sandfly specimens collected from chicken pens and sheep pens. Phylogenetic analyses of the L, M and S gene segments of the viruses revealed that the four virus strains represented the previously isolated WUXV. The minimum infection rate (MIR) of the virus isolated from the sheep pen was 3.21, and the MIR of the virus isolated from the chicken pen was 3.45. The positive rates of Wuxiang virus neutralizing antibodies in serum samples of local healthy people and domestic chickens were 8.7% (4/46) and 100% (4/4), respectively, suggesting that Wuxiang virus can infect human and animal. In view of the fact that Wuxiang virus is infectious to humans and animals and has a relatively wide geographical distribution in China, it is of great public health significance to strengthen the investigation and study on the infection status of Wuxiang virus in humans and animals.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12250-021-00398-4.

(Invited) Agriculture 4.0: Development of Chemical and Biochemical Smart Sensors Systems for Sustainable Food Production

IntroductionWith the global population expected to grow to over 9.6 billion by 2050 it is a projected that a 50-60 % increase in food production will be required. In addition, the increasing wealth of the BRIC (Brazil, Russia, India and China) countries is driving the transition from traditional to more westernized high protein diets. A key challenge then, going forward, will be to close the food gap. This must be achieved against the backdrop of climate change & desertification, labor shortages and competition for energy, land & resources. It is clear then, that addressing this challenge will require the development of more efficient and sustainable food production techniques and processes. Digitizing the entire food chain using smart sensor systems would help enable such an approach. This convergence between the Internet of Things (IoT) and the agri-food industry requires sensor systems and technologies that provide real time data to producers and processers; required for rapid, but informed, decision making. To this end, we are using microelectronic fabrication approaches to develop advanced end-to-end chemical and bio-chemical nanosensor sensor systems specifically tailored to the needs of both producers and processors [1-3]. These sensor systems are being designed to be used by non-specialists and be rugged enough for field deployment [4, 5].Sensor DevelopmentOn-chip devices containing six gold microband electrodes, a gold counter and a platinum pseudo-reference electrodes were fabricated using standard nanofabrication processes on Si/SiO2 substrates as described in detail previously [6]. A custom built Teflon cell permit analysis of small sample volumes (~50 µL), see Fig 1. Gold contact pads were configured on-chip to permit electrical connection to the potentiostat via a microSD port. Chips could be easily plugged in/out enabling rapid analysis of multiple samples. Optical micrographs were acquired using a calibrated microscope (Axioskop II, Carl Zeiss Ltd.) with a charge-coupled detector camera (CCD; DEI-750, Optronics). Electrochemical experiments were carried out using an Autolab Potentiostat/ Galvanostat PGSTAT128N (Metrohm Ltd, Utrecht, The Netherlands) controlled by the Autolab NOVA software. All experiments employed a standard three-electrode cell configuration using a single gold nanoband as the working electrode, versus the on-chip gold counter and platinum pseudo-reference electrodes,. In this study, microband sensors were applied to the detection of Bovine IgG and anti-Fasciola antibodies in serum samples. On-chip microband electrodes were first cleaned using a mixed solvent clean process (acetone, isopropyl alcohol and DI water) for 15 minutes. Cyclic voltammetry was then employed for electropolymerisation of o-aminobenzoic acid (o-ABA, 50 mM in 0.5 M H2SO4) to create a carboxylic terminated polymer layer at the gold electrode surface. A fresh NHS/EDC mixture was prepared in 10 mM acetate buffer, pH 4.0 and subsequently deposited onto the polymerised electrodes, for approximately 30 min, to activate the surface. Concerning IgG, activated electrodes were modified with 1 ng/ml anti-Bovine IgG in 10 mM sodium acetate buffer, pH 4.0 (AB). Anti-IgG was incubated on the electrode for 15 min. Following deposition of these capture biomolecules, unbound active-sites on all electrodes were blocked with ethanolamine (1 M) for 20 minutes. A secondary blocking of 1 % NANNY care® goat based milk in PBS was used for the IgG assay, for a comparison. Results and Conclusions Electrochemical Impedance Spectroscopy (EIS) techniques allows for the monitoring of the increase of the Rct signal and was used to interrogate antigen binding. The reduction of the electron transfer causes an increase in the Rct as seen in Figure 2. Following exposure to igG antibodies an increase in impedance was observed. A semi-logarithmic relationship exists between the concentration of the target and the change in Rct. This correlates with the trend seen in the ELISA calibration plot. The Nyquist plot shows a much larger change in signal between each concentration of Bo IgG than the CV and thus EIS is widely used for evaluating immunosensors such as these.

Dynamics and Extent of Non-Structural Protein 1-Antibody Responses in Tick-Borne Encephalitis Vaccination Breakthroughs and Unvaccinated Patients.

Tick-borne encephalitis (TBE) has a substantial impact on human public health in many parts of Europe and Asia. Effective inactivated purified whole-virus vaccines are in widespread use in TBE-endemic countries. Nevertheless, vaccination breakthroughs (VBTs) with manifest clinical disease do occur, and their specific serodiagnosis was shown to be facilitated by the detection of antibodies to a non-structural protein (NS1) that is produced during virus replication. However, recent data have shown that NS1 is also present in the current inactivated vaccines, with the potential of inducing corresponding antibodies and obscuring a proper interpretation of NS1-antibody assays for diagnosing VBTs. In our study, we quantified anti-virion and anti-NS1 antibody responses after vaccination as well as after natural infection in TBE patients, both without and with a history of previous TBE vaccination (VBTs). We did not find significant levels of NS1-specific antibodies in serum samples from 48 vaccinees with a completed vaccination schedule. In contrast, all TBE patients mounted an anti-NS1 antibody response, irrespective of whether they were vaccinated or not. Neither the dynamics nor the extent of NS1-antibody formation differed significantly between the two cohorts, arguing against substantial NS1-specific priming and an anamnestic NS1-antibody response in VBTs.

Seropositive coronavirus disease 2019 detection among apparently healthy voluntary blood donors

Background Despite the prevailing pandemic of coronavirus disease 2019, there are no recommendations available yet for serological screening of apparently healthy asymptomatic blood donors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. Objective To explore the seropositivity for SARS-CoV-2 antibodies in serum samples of a group of randomly selected Egyptian voluntary blood donors who met the eligibility criteria for blood donation as a preliminary step to catch apparently healthy asymptomatic participants who constitute an important source of viral spread in the community. Patients and methods The first phase of our study design plan included 100 anonymous serum samples of a group of voluntary blood donors who donated blood at Ain-Shams University Hospitals’ blood bank during the period from the second week of September to the end of October 2020. After completion of the steps of donation, donors’ stored serum samples were screened for SARS-CoV-2-specific immunoglobulin (Ig)M and IgG antibodies. The next phase of our study design plan is intended to include larger samples of known apparently healthy asymptomatic blood donors in an attempt to reach seropositive patients to confirm the results by PCR and validate the testing. Results A total of 100 anonymous serum samples were included in the study. Eleven (11%) samples were reactive for viral specific IgM antibodies, and 38 (38%) samples were reactive for viral specific IgG antibodies. Conclusion As the ongoing pandemic of coronavirus disease 2019 is continuing to demand urgent attention, screening of all asymptomatic apparently healthy voluntary blood donors for SARS-CoV-2 antibodies followed by viral RNA detection by PCR in seropositive donors could abort viral spread to others in blood centers and eventually to the rest of the community.

Foxp3 Silencing with Antisense Oligonucleotide Improves Immunogenicity of an Adjuvanted Recombinant Vaccine against Sporothrix schenckii.

Background: In recent years, there has been great interest in developing molecular adjuvants based on antisense oligonucleotides (ASOs) targeting immunosuppressor pathways with inhibitory effects on regulatory T cells (Tregs) to improve immunogenicity and vaccine efficacy. We aim to evaluate the immunostimulating effect of 2′OMe phosphorothioated Foxp3-targeted ASO in an antifungal adjuvanted recombinant vaccine. Methods: The uptake kinetics of Foxp3 ASO, its cytotoxicity and its ability to deplete Tregs were evaluated in murine splenocytes in vitro. Groups of mice were vaccinated with recombinant enolase (Eno) of Sporothix schenckii in Montanide Gel 01 adjuvant alone or in combination with either 1 µg or 8 µg of Foxp3 ASO. The titers of antigen-specific antibody in serum samples from vaccinated mice (male C57BL/6) were determined by ELISA (enzyme-linked immunosorbent assay). Cultured splenocytes from each group were activated in vitro with Eno and the levels of IFN-γ and IL-12 were also measured by ELISA. The results showed that the anti-Eno antibody titer was significantly higher upon addition of 8 µM Foxp3 ASO in the vaccine formulation compared to the standard vaccine without ASO. In vitro and in vivo experiments suggest that Foxp3 ASO enhances specific immune responses by means of Treg depletion during vaccination. Conclusion: Foxp3 ASO significantly enhances immune responses against co-delivered adjuvanted recombinant Eno vaccine and it has the potential to improve vaccine immunogenicity.

Pemisahan dan Penentuan Karakter Fraksi Protein ESA Toxoplasma gondii Secara ImmunologikUntuk Pengembangan Diagnosa

Toxoplasmosis is a zoonotic disease that attacks vertebrates including humans. T gondi infection cause toxoplasmic encephalitis in immunocompromised patients, blindness, abortion, fetal abnormalities and even fetal death or miscarriage. the diagnosis of toxoplasmosis is mainly based on detection of specific antibodies in serum samples using the T gondii antigen protein. various kinds of antigens are explored to be used as bioresptors to detect antibodies against T gondii in the patient's body. the use of ESA protein has advantages in terms of simple preparation. The lacks is the protein contamination by extraparasitic components so that it can reduce the sensitivity and specificity of T gondii antibodies detection. The purpose of this study is to separate or purify antigenic ESA proteins to increase the sensitivity and specificity detection by purifying ESA proteins with gel filtration chromatography. The results obtained 3 fractionation, the protein ESA fractionation is one of fraction that has antigenic properties towards T Gondii. dipstick test with antigen using fraction 3 the results of ESA protein fractionation, 7 samples were positive from 8 positive samples, gave a sensitivity value of 87.5% and 6 samples were negative from 8 negative samples, giving a specificity value of 75%.

Prevalence of heterophilic antibodies in serum samples from horses in an equine hospital, and elimination of interference using chicken IgY

BackgroundHeterophilic antibodies in serum and plasma can interfere with mammalian antibodies in immunoassays and result in false test results, usually false positive. Although studies screening for heterophilic antibodies as well as elimination studies have been conducted in dogs and cats, knowledge of the presence of heterophilic antibodies in other species in veterinary medicine is limited. In this study, a 2-site sandwich-type interference assay that detects anti-mouse antibodies was used to detect heterophilic antibodies in a population of horses treated in an animal hospital.ResultsA total of 194 serum samples from 127 individual horses were analyzed. There were 11/127 (8.7%) interference-positive horses, and these were analyzed in an assay exchanging the capture mouse IgG with chicken IgY. The positive samples were negative in the chicken IgY assay, indicating elimination of a possible interference, with the chicken-based assay. Four interference-positive samples were from geldings, and anti-Müllerian hormone (AMH) was analyzed from these samples. AMH concentrations were negative in these samples as expected in geldings, indicating that the heterophilic antibodies did not cause interference in the AMH assay.ConclusionThe present study shows that there are heterophilic antibodies in horse serum samples like in samples from humans, dogs, and cats. The use of chicken-based reagents, such as chicken IgY, which do not cross-react with mammalian IgG, eliminates the effects of interfering antibodies in the samples. Equine heterophilic antibodies do not necessarily cause interference in commercial immunoassays.

Durability of the humoral immune response in recovered COVID-19 patients.

BackgroundThe immunological factors involved in protection against the disease caused by SARS-CoV-2 are insufficiently defined and understood. However, previous knowledge pertaining to the related SARS virus and other human coronaviruses may prove useful. Population-based serosurveys measuring anti-SARS-CoV-2 antibodies may provide a pattern for estimating infection degrees and observing the development of the epidemic. In this study, we aimed to investigate the persistence of antibody against the SARS-CoV-2 in recovered patients in Al Madinah region of Saudi Arabia.Materials and methodsA total of 150 recovered COVID-19 patients participated in this study. All the patients tested positive for the presence of SARS-CoV-2 RNA, using qualitative RT-PCR. An ELISA was used to measure anti-Spike (S) IgG antibodies in serum samples and screen for their persistence at various time points post-infection.ResultsThe patients were categorized as asymptomatic (27.3%), mild (28%) and moderate (44.7%) according to the disease severity. Amongst them, 35.3% were females (n = 53) and 64.7% were males (n = 97). Significant anti-S IgG antibody levels were observed among the different groups, with the patients in moderate group exhibiting the highest levels followed by the mild group; while the lowest levels were detected among the asymptomatic. There was a significant positive correlation between the patients’ age and anti-S IgG antibody concentrations (Pearson r = 0.45; p < 0.001).ConclusionOur findings provide a solid evidence to support the use of an anti-S IgG ELISA as a diagnostic tool to indicate SARS-CoV-2 infection. IgG seropositivity was sustained in recovered patients up to a hundred days' post-infection, the latest time point for antibody measurement in our study. Ours is the first report in Saudi Arabia to investigate the durability of humoral immune response in recovered COVID-19 patients.

Seasonal human coronavirus antibodies are boosted upon SARS-CoV-2 infection but not associated with protection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread within the human population. Although SARS-CoV-2 is a novel coronavirus, most humans had been previously exposed to other antigenically distinct common seasonal human coronaviruses (hCoVs) before the coronavirus disease 2019 (COVID-19) pandemic. Here, we quantified levels of SARS-CoV-2-reactive antibodies and hCoV-reactive antibodies in serum samples collected from 431 humans before the COVID-19 pandemic. We then quantified pre-pandemic antibody levels in serum from a separate cohort of 251 individuals who became PCR-confirmed infected with SARS-CoV-2. Finally, we longitudinally measured hCoV and SARS-CoV-2 antibodies in the serum of hospitalized COVID-19 patients. Our studies indicate that most individuals possessed hCoV-reactive antibodies before the COVID-19 pandemic. We determined that ∼20% of these individuals possessed non-neutralizing antibodies that cross-reacted with SARS-CoV-2 spike and nucleocapsid proteins. These antibodies were not associated with protection against SARS-CoV-2 infections or hospitalizations, but they were boosted upon SARS-CoV-2 infection.

Improving the diagnosis of bovine tuberculosis using gold nanoparticles conjugated with purified protein derivative: special regard to staphylococcal protein A and streptococcal protein G.

Different ancillary immunodiagnostic tests were traditionally-established for diagnosis of bovine tuberculosis (BTB) either cellular or humoral as tuberculin skin test (TST), gamma interferon (INF-γ), and indirect enzyme-linked immunosorbent assay (iELISA). These tests had been consumed more time and expensive, and needed sophisticated equipment. To dissolve these problems, serological diagnosis depending on humoral immunity is the aim of this work. Herein, slide-based agglutination test was chosen as a rapid and simple field test based on purified protein derivative (PPD) antigen in addition to some supplementation materials such as Staphylococcal protein A (SPA) and Streptococcal protein G (SPG) to improve detection of BTB antibody in serum samples. Gold nanoparticles (Au NPs) were synthesized by gamma ray, and after complete characterization, the synthesized Au NPs were spherical, small-sized, and stable without any impurities. Addition of such supplementation reagents for serodiagnosis of tuberculosis is of paramount important for the detection of serum antibodies against tuberculosis (TB) and it was considered an easily simple and possible way for improving TB diagnosis. In this work, 70 animals tested positive for TST as well as 20 animals tested negative for TST were used for the diagnosis of BTB depending on humoral immune response based on PPD slide agglutination test using reporter regents (SPA and/or SPG) either native or recombinant. The agglutination density was recorded and read in 4 degrees of positivity with scores ranging from negative (-) to very strong reaction (++++) occurred in different times of agglutination. Groups showed 100% positive reactivates employed in Exp. 1, 2, and 3 with differentiation of slide agglutination test density and was rated from moderate positivity (2+) to very strong (4+), with predominant positivity in density of (3+). Pink-colored intensity is associated with the strengthened reactions between PPD-conjugated Au NPs and serum antibody of each tested samples, which allows for visual rapid, simple, and effective attractive diagnosis of BTB. The specificity and sensitivity of the serological tests were characterized. TST offers the highest sensitivity (83.6%) among the other immunoassays, while the lowest specificity was recorded in TST (57.4%). SPA/SPG offers the best performance in term of combined sensitivity and specificity (performance index) of 175.4. Therefore, the development and uses of detection reagent (such as SPA and/or SPG) slide co-agglutination test (COAT), either native or recombinant (rSPA/SPG) for the detection of TB antibodies based on PPD antigen, as well as the uses of Au NPs rSPA/SPG as detection conjugate based on the same antigen, were also performed as a simple, rapid, sensitive, specific, eco-friendly, and low cost, which shows a great potential in field and lab diagnosis of BTB. So, high reduction in reagents that yields reactions similarly as traditional techniques was needed.

Atypical anti-glomerular basement membrane disease with anti-GBM antibody negativity and ANCA positivity: a case report

BackgroundAnti-glomerular basement membrane (anti-GBM) disease is an organ-specific autoimmune disease that involves the lung and kidneys and leads to rapid glomerulonephritis progression, with or without diffuse alveolar hemorrhage, and even respiratory failure. Classic cases of anti-GBM disease are diagnosed based on the presence of the anti-GBM antibody in serum samples and kidney or lung biopsy tissue samples. However, atypical cases of anti-GBM disease are also seen in clinical practice.Case presentationWe herein report the rare case of a patient with atypical anti-GBM disease whose serum was negative for the anti-GBM antibody but positive for the myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibody (p-ANCA) and another atypical ANCA. Laboratory test results showed severe renal insufficiency with a creatinine level of 385 μmol/L. Renal biopsy specimen analysis revealed 100% glomeruli with crescents; immunofluorescence showed immunoglobulin G (IgG) linearly deposited alongside the GBM. Finally, the patient was discharged successfully after treatment with plasmapheresis, methylprednisolone and prednisone.ConclusionThis patient, whose serum was negative for the anti-GBM antibody but positive for p-ANCA and another atypical ANCA, had a rare case of anti-GBM disease. Insights from this unusual case might help physicians diagnose rare forms of glomerulonephritis and treat affected patients in a timely manner.

A prospective surveillance study on the kinetics of the humoral immune response to the respiratory syncytial virus fusion protein in adults in Houston, Texas

Respiratory syncytial virus (RSV)-specific serum antibody has been correlated to protection of infection and reduction of severe disease, but reinfection is still frequent. In this study, we evaluated RSV-specific serum antibody activity following natural RSV re-infection to examine the longevity of the humoral immune response in adults. Nineteen healthy adult volunteers under sixty-five years of age were enrolled during the 2018–2019 RSV season in Houston, TX. Blood was collected at three study visits. The kinetics of RSV-neutralizing, RSV F site-specific competitive, and RSV-binding antibodies in serum samples were measured by microneutralization and enzyme-linked immunosorbent assays. Three distinct profiles of RSV-specific antibody kinetics were identified that were consistent with RSV infection status: uninfected, acutely infected, and recently infected. The uninfected group had stable antibody titers for the duration of the study period (185 days). The acutely infected group had lower antibody responses at the beginning of the study, supporting a correlate of infection, followed by a significant antibody response after infection that was maintained for at least 125 days. Unlike the acutely infected group, the recently infected group had a significant precipitous decrease in RSV antibody in only 60 days. This study is the first, to our knowledge, to describe this abrupt loss of RSV-specific antibody in detail. This rapid decline of antibody may present an obstacle for the development of vaccines with lasting protection against RSV, and perhaps other respiratory pathogens. Neutralizing antibody responses were greater to prototypic than contemporaneous RSV strains, regardless of infection status, indicating that original antigenic sin may impact the humoral immune response to new or emerging RSV strains.

Insight into the practical performance of RT-PCR testing for SARS-CoV-2 using serological data: a cohort study

SummaryBackgroundVirological detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through RT-PCR has limitations for surveillance. Serological tests can be an important complementary approach. We aimed to assess the practical performance of RT-PCR-based surveillance protocols and determine the extent of undetected SARS-CoV-2 infection in Shenzhen, China.MethodsWe did a cohort study in Shenzhen, China and attempted to recruit by telephone all RT-PCR-negative close contacts (defined as those who lived in the same residence as, or shared a meal, travelled, or socially interacted with, an index case within 2 days before symptom onset) of all RT-PCR-confirmed cases of SARS-CoV-2 detected since January, 2020, via contact tracing. We measured anti-SARS-CoV-2 antibodies in serum samples from RT-PCR-negative close contacts 2–15 weeks after initial virological testing by RT-PCR, using total antibody, IgG, and IgM ELISAs. In addition, we did a serosurvey of volunteers from neighbourhoods with no reported cases, and from neighbourhoods with reported cases. We assessed rates of infection undetected by RT-PCR, performance of RT-PCR over the course of infection, and characteristics of individuals who were seropositive on total antibody ELISA but RT-PCR negative.FindingsBetween April 12 and May 4, 2020, we enrolled and collected serological samples from 2345 (53·0%) of 4422 RT-PCR-negative close contacts of cases of RT-PCR-confirmed SARS-CoV-2. 1175 (50·1%) of 2345 were close contacts of cases diagnosed in Shenzhen with contact tracing details, and of these, 880 (74·9%) had serum samples collected more than 2 weeks after exposure to an index case and were included in our analysis. 40 (4·5%) of 880 RT-PCR-negative close contacts were positive on total antibody ELISA. The seropositivity rate with total antibody ELISA among RT-PCR-negative close contacts, adjusted for assay performance, was 4·1% (95% CI 2·9–5·7), which was significantly higher than among individuals residing in neighbourhoods with no reported cases (0·0% [95% CI 0·0–1·1]). RT-PCR-positive individuals were 8·0 times (95% CI 5·3–12·7) more likely to report symptoms than those who were RT-PCR-negative but seropositive, but both groups had a similar distribution of sex, age, contact frequency, and mode of contact. RT-PCR did not detect 48 (36% [95% CI 28–44]) of 134 infected close contacts, and false-negative rates appeared to be associated with stage of infection.InterpretationEven rigorous RT-PCR testing protocols might miss a substantial proportion of SARS-CoV-2 infections, perhaps in part due to difficulties in determining the timing of testing in asymptomatic individuals for optimal sensitivity. RT-PCR-based surveillance and control protocols that include rapid contact tracing, universal RT-PCR testing, and mandatory 2-week quarantine were, nevertheless, able to contain community spread in Shenzhen, China.FundingThe Bill & Melinda Gates Foundation, Special Foundation of Science and Technology Innovation Strategy of Guangdong Province, and Key Project of Shenzhen Science and Technology Innovation Commission.

The role of pseudotype neutralization assays in understanding SARS CoV-2.

Abstract Neutralisation assays are crucial tools to quantify the presence of functional neutralising antibodies in serum samples. Since the SARS-CoV-2 virus (the causative agent of COVID-19) is designated as a category 3 biosafety level pathogen, pseudotyped viruses bearing the SARS-CoV-2 spike protein permit extensive and widespread serum/plasma screening in a BSL 2 laboratory. These assays can be used to assess viral tropism, vaccine immunogenicity, efficacy of antiviral compounds (incl. therapeutic mAbs) and serosurveillance studies. In this article, we highlight approaches to SARS-CoV-2 viral pseudotyping, its practicality, and utility in increasing our understanding of neutralising antibodies against SARS-CoV-2.

Translational Bioinformatics of HIV Peptide 2.0: From Dry To Wet Bench

Infectious diseases have become part of human civilization as a constant phenomenon throughout time. The Human Immunodeficiency Virus (HIV) is a virus that can cause immune system weakness by attacking cells that have CD4 receptors and CCR5 or CXCR4 chemokine coreceptors, namely helper T cells macrophages and dendritic cells. Therefore, people infected with this virus will be vulnerable to opportunistic infections and cancer. Here we proposed the translational bioinformatics approach from dry to wet bench. From proof of concept to the applications will be highlighted and discussed further in diagnostic of HIV and vaccine candidate development based on reverse vaccinology approach. We performed sequence data analysis to find the best epitope for HIV strains in Indonesia and compatible with the MHC class 1, the linear core with MHC class 2, and the B cell epitope. Epitope compatible with the two cells is expected to have high immunogenicity and potentially produce a response to good T memory. The epitope was then tested using an indirect ELISA against the serum of HIV positive patients. In this study, a negative control is used in blood serum from healthy individuals originating from Stored Biological Material and carried out with a commercial ELISA kit for the negative controls. The epitope in PBS buffer solution was coated to a microplate with an incubation time of 16 hours and various concentrations. As a result, the epitope from the concentration range of 1-2500 ng epitope/well can be recognized by HIV patient antibodies. In summary, the epitope from the in silico prediction had antigenicity against anti-HIV antibodies in sera samples and could also be a promising candidate for the vaccine.