Platelet-derived major histocompatibility complex class I coating on Treponema pallidum attenuates natural killer cell lethality.

The evasive tactics of Treponema pallidum pose a major challenge in combating and eradicating syphilis. Natural killer (NK) cells mediate important effector functions in the control of pathogenic infection, preferentially eliminating targets with low or no expression of major histocompatibility complex (MHC) class I. To clarify T. pallidum's mechanisms in evading NK-mediated immunosurveillance, experiments were performed to explore the cross-talk relations among T. pallidum, NK cells, and platelets. T. pallidum adhered to, activated, and promoted particle secretion of platelets. After preincubation with T. pallidum, platelets expressed and secreted high levels of MHC class I, subsequently transferring them to the surface of T. pallidum, potentially inducing an immune phenotype characterized by the "pseudo-expression" of MHC class I on the surface of T. pallidum (hereafter referred to a "pseudo-expression" of MHC class I). The polA mRNA assay showed that platelet-preincubated T. pallidum group exhibited a significantly higher copy number of polA transcript than the T. pallidum group. The survival rate of T. pallidum mirrored that of polA mRNA, indicating that preincubation of T. pallidum with platelets attenuated NK cell lethality. Platelets pseudo-expressed the MHC class I ligand on the T. pallidum surface, facilitating binding to killer cell immunoglobulin-like receptors with two immunoglobulin domains and long cytoplasmic tail 3 (KIR2DL3) on NK cells and initiating dephosphorylation of Vav1 and phosphorylation of Crk, ultimately attenuating NK cell lethality. Our findings elucidate the mechanism by which platelets transfer MHC class I to the T. pallidum surface to evade NK cell immune clearance.

Two-Stage Deep Learning Model for Diagnosis of Lumbar Spondylolisthesis Based on Lateral X-Ray Images.

BACKGROUND: Diagnosing early lumbar spondylolisthesis is challenging for many doctors because of the lack of obvious symptoms. Using deep learning (DL) models to improve the accuracy of X-ray diagnoses can effectively reduce missed and misdiagnoses in clinical practice. This study aimed to use a two-stage deep learning model, the Res-SE-Net model with the YOLOv8 algorithm, to facilitate efficient and reliable diagnosis of early lumbar spondylolisthesis based on lateral X-ray image identification. METHODS: A total of 2424 lumbar lateral radiographs of patients treated in the Beijing Tongren Hospital between January 2021 and September 2023 were obtained. The data were labeled and mutually identified by 3 orthopedic surgeons after reshuffling in a random order and divided into a training set, validation set, and test set in a ratio of 7:2:1. We trained 2 models for automatic detection of spondylolisthesis. YOLOv8 model was used to detect the position of lumbar spondylolisthesis, and the Res-SE-Net classification method was designed to classify the clipped area and determine whether it was lumbar spondylolisthesis. The model performance was evaluated using a test set and an external dataset from Beijing Haidian Hospital. Finally, we compared model validation results with professional clinicians' evaluation. RESULTS: The model achieved promising results, with a high diagnostic accuracy of 92.3%, precision of 93.5%, and recall of 93.1% for spondylolisthesis detection on the test set, the area under the curve (AUC) value was 0.934. CONCLUSIONS: Our two-stage deep learning model provides doctors with a reference basis for the better diagnosis and treatment of early lumbar spondylolisthesis.

Treponema pallidum Promotes the Polarization of M2 Subtype Macrophages to M1 Subtype Mediating the Apoptosis and Inhibiting the Angiogenesis of Human Umbilical Vein Endothelial Cells.

M2 macrophages were related to local immune homeostasis and maternal-fetal tolerance in normal pregnancy; whether M2 macrophages can respond to the stimulation of Treponema pallidum to mediate placental vascular inflammation injury is unclear. In this study, M2 macrophages were constructed to investigate the impact of T. pallidum on macrophage polarization and the underlying signaling pathway involved in this process, and the influence of macrophage polarization triggered by T. pallidum on the apoptosis and angiogenesis of human umbilical vein endothelial cells (HUVEC) was also explored. The results showed that M2 macrophage markers (CD206 and PPARγ) and anti-inflammatory factors (TGFß and CCL18) were decreased, while M1 macrophage marker CD80 and inflammatory cytokines (IL1ß and TNFα) were increased when M2 macrophages were treated with T. pallidum, indicating that T. pallidum promoted the polarization of M2 subtype macrophages to the M1 subtype. Moreover, T. pallidum-induced M1 macrophage polarization was found to be significantly correlated with the activation of Janus kinase 1 (JAK1) and signal transducer and activator of transcription 1 (STAT1). In addition, T. pallidum-induced M1 macrophages were found to promote apoptosis and inhibit the angiogenesis of HUVECs, and JAK1 or STAT1 inhibitors could weaken the apoptosis rate and promote the angiogenesis of HUVECs. These findings revealed that T. pallidum promoted the polarization of M2 macrophages to the M1 subtype through the JAK1-STAT1 signal pathway mediating the apoptosis and inhibiting angiogenesis of HUVECs, which may provide a possible mechanism for T. pallidum-induced adverse pregnancy outcomes.

Screening the B- and T-cell epitope map of TP0136 and exploring their effect in a Treponema pallidum rabbit model.

The systemic immune response, including B- and T-cell reactions, plays a corresponding role in syphilis infections. The TP0136 protein is a target of the immune response in infected hosts and may mediate the immune response. Here, we developed a method that combining reverse vaccine approach with Pepscan/T-cell proliferation to screen and identify three B-cell and two T-cell epitopes of TP0136, and explore the role of the B- and T-cell epitopes in immunized-infected animals. The results showed that immunized with B-cell epitopes not only had no protective effect but also aggravated the syphilitic lesion development. While immunized with T-cell epitopes of TP0136 could induce a strong Th1-cellular immunity response, which could attenuate syphilitic lesion development to a certain extent. The variation in exacerbation or attenuation of skin lesions, induced by distinct B- and T-cell epitopes of Tp0136, within the host's defense against syphilis warrants in-depth exploration.

Insights into the protective immune response by immunization with full-length recombinant TprK protein: cellular and humoral responses.

Syphilis has resurged in many countries, which has called attention to vaccine development. Based on the immunization-based rabbit model of infection with the Nichols strain, this study explored the protective immune response of a controversial syphilis vaccine candidate, TprK, and found that immunization with full-length rTprK was effective in attenuating lesion development and accelerating lesion resolution, which could reduce the probability of the pathogen spreading to distant tissue sites to prevent the progression of the disease to some extent. Furthermore, the results revealed that immunization with rTprK not only rapidly induced a strong Th1-like cellular response but also elicited a humoral immune response to produce opsonic antibodies to enhance macrophage-mediated opsonophagocytosis. Although complete protection against infection was not achieved, the study provided a comprehensive and in-depth exploration of the immunogenicity of TprK and highlighted the importance of TprK as a promising syphilis vaccine component.

Diagnosis of neurosyphilis in HIV-negative patients with syphilis: development, validation, and clinical utility of a suite of machine learning models.

Background: The ability to accurately identify the absolute risk of neurosyphilis diagnosis for patients with syphilis would allow preventative and therapeutic interventions to be delivered to patients at high-risk, sparing patients at low-risk from unnecessary care. We aimed to develop, validate, and evaluate the clinical utility of simplified clinical diagnostic models for neurosyphilis diagnosis in HIV-negative patients with syphilis. Methods: We searched PubMed, China National Knowledge Infrastructure and UpToDate for publications about neurosyphilis diagnostic guidelines in English or Chinese from database inception until March 15, 2023. We developed and validated machine learning models with a uniform set of predictors based on six authoritative diagnostic guidelines across four continents to predict neurosyphilis using routinely collected data from real-world clinical practice in China and the United States (through the Dermatology Hospital of Southern Medical University in Guangzhou [659 recruited between August 2012 and March 2022, treated as Development cohort], the Beijing Youan Hospital of Capital Medical University in Beijng [480 recruited between December 2013 and April 2021, treated as External cohort 1], the Zhongshan Hospital of Xiamen University in Xiamen [493 recruited between November 2005 and November 2021, treated as External cohort 2] from China, and University of Washington School of Medicine in Seattle [16 recruited between September 2002 and April 2014, treated as External cohort 3] from United States). We included all these patients with syphilis into our analysis, and no patients were further excluded. We trained eXtreme gradient boosting (XGBoost) models to predict the diagnostic outcome of neurosyphilis according to each diagnostic guideline in two scenarios, respectively. Model performance was measured through both internal and external validation in terms of discrimination and calibration, and clinical utility was evaluated using decision curve analysis. Findings: The final simplified clinical diagnostic models included neurological symptoms, cerebrospinal fluid (CSF) protein, CSF white blood cell, and CSF venereal disease research laboratory test/rapid plasma reagin. The models showed good calibration with rescaled Brier score of 0.99 (95% CI 0.98-1.00) and excellent discrimination (the minimum value of area under the receiver operating characteristic curve, 0.84; 95% CI 0.81-0.88) when externally validated. Decision curve analysis demonstrated that the models were useful across a range of neurosyphilis probability thresholds between 0.33 and 0.66 compared to the alternatives of managing all patients with syphilis as if they do or do not have neurosyphilis. Interpretation: The simplified clinical diagnostic models comprised of readily available data show good performance, are generalisable across clinical settings, and have clinical utility over a broad range of probability thresholds. The models with a uniform set of predictors can simplify the sophisticated clinical diagnosis of neurosyphilis, and guide decisions on delivery of neurosyphilis health-care, ultimately, support accurate diagnosis and necessary treatment. Funding: The Natural Science Foundation of China General Program, Health Appropriate Technology Promotion Project of Guangdong Medical Research Foundation, Department of Science and technology of Guangdong Province Xinjiang Rural Science and Technology（Special Commissioner）Project, Southern Medical University Clinical Research Nursery Garden Project, Beijing Municipal Administration of Hospitals Incubating Program.

The optimum condition of the toluidine red unheated serum test for the replacement of the venereal disease research laboratory test in cerebrospinal fluid for neurosyphilis diagnosis.

Background: The cerebrospinal fluid (CSF) venereal disease research laboratory (VDRL) test remains the standard for the laboratory diagnosis of neurosyphilis. The toluidine red unheated serum test (TRUST) is an alternative to the VDRL test as a serological test for syphilis, but it lacks guidelines for its use in CSF for neurosyphilis diagnosis. Methods: A total of 210 suspected neurosyphilis patients were included, consisting of 124 neurosyphilis patients and 86 syphilis/non-neurosyphilis patients. The TRUST was modified into the CSF-TRUST-10 test with 10 µL of antigen by referring to the CSF-VDRL test, and the CSF-TRUST-17 test with 17 µL of antigen by referring to its procedures in serum. The diagnostic performance of the CSF-TRUST-10 and CSF-TRUST-17 tests and the concordance between them and the CSF-VDRL test were evaluated. Results: The diagnostic performance of the CSF-TRUST-10 and CSF-TRUST-17 tests for diagnosing neurosyphilis were comparable to the CSF-VDRL test, as well as the positive rate. The agreement rate was 98.7% between the qualitative CSF-TRUST-10 and CSF-VDRL tests. A total of 91.4% of the quantitative CSF-TRUST-10 results were consistent with the CSF-VDRL test, and the discordant results were no more than two titres. The agreement rate was 98.1% between the qualitative CSF-TRUST-17 and CSF-VDRL tests and 87.6% between the quantitative CSF-TRUST-17 and CSF-VDRL tests. Conclusions: The CSF-TRUST with 10 µL of antigen could be an alternative for the CSF-VDRL test for neurosyphilis diagnosis. Our results provide a basis for using the TRUST to guide the diagnosis of neurosyphilis.

Treponema pallidum membrane protein Tp47 induced autophagy and inhibited cell migration in HMC3 cells via the PI3K/AKT/FOXO1 pathway.

The migratory ability of microglia facilitates their rapid transport to a site of injury to kill and remove pathogens. However, the effect of Treponema pallidum membrane proteins on microglia migration remains unclear. The effect of Tp47 on the migration ability and autophagy and related mechanisms were investigated using the human microglial clone 3 cell line. Tp47 inhibited microglia migration, the expression of autophagy-associated protein P62 decreased, the expression of Beclin-1 and LC3-II/LC3-I increased, and the autophagic flux increased in this process. Furthermore, autophagy was significantly inhibited, and microglial cell migration was significantly increased after neutralisation with an anti-Tp47 antibody. In addition, Tp47 significantly inhibited the expression of p-PI3K, p-AKT, and p-mTOR proteins, and the sequential activation of steps in the PI3K/AKT/mTOR pathways effectively prevented Tp47-induced autophagy. Moreover, Tp47 significantly inhibited the expression of p-FOXO1 protein and promoted FOXO1 nuclear translocation. Inhibition of FOXO1 effectively suppressed Tp47-induced activation of autophagy and inhibition of migration. Treponema pallidum membrane protein Tp47-induced autophagy and inhibited cell migration in HMC3 Cells via the PI3K/AKT/FOXO1 pathway. These data will contribute to understanding the mechanism by which T. pallidum escapes immune killing and clearance after invasion into the central nervous system.

Treponema pallidum recombinant protein Tp47 enhanced interleukin-6 secretion in human dermal fibroblasts through the toll-like receptor 2 via the p38, PI3K/Akt, and NF-κB signalling pathways.

Interleukin-6 (IL-6) is a multi-effective cytokine involved in multiple immune responses. Whether fibroblasts also turn out to be a cytokine IL-6 factory during interaction with Treponema pallidum is not yet understood. To explore whether fibroblasts participate in inflammation due to syphilis, a series of experiments were performed to explore the role of T. pallidum lipoprotein Tp47 in IL-6 production in human dermal fibroblasts. The Toll-like receptor 2 (TLR2) and participating signalling pathways in this process were also evaluated. The results showed that the expressions of IL-6 and the protein levels of TLR2 in fibroblasts were upregulated after stimulation with Tp47, and this effect was impeded by the TLR2 inhibitor C29. In addition, Tp47 promoted the phosphorylation of p38, PI3K/Akt, and nuclear factor-kappaB (NF-κB), and the translocation of NF-κB in fibroblasts. Moreover, p38, PI3K, and NF-κB inhibitors significantly reduced IL-6 production in fibroblasts stimulated with Tp47. Furthermore, the TLR2 inhibitor C29 inhibited the phosphorylation of p38, Akt, and NF-κB, and the translocation of NF-κB in fibroblasts. In conclusion, our results showed that Tp47 enhanced IL-6 secretion in human dermal fibroblasts through TLR2 via p38, PI3K/Akt, and NF-κB signalling pathways. These findings contribute to our understanding of syphilis inflammation.

Remediation and resource utilization of petroleum-contaminated soil by pyrite-assisted pyrolysis as bifunctional materials to adsorb heavy metal and activate peroxymonosulfate oxidation.

Petroleum-contaminated soil (PCS) requires not only efficient remediation technology but also economically viable reuse strategy of remediated soil with vast volume. This study developed a pyrite-assisted pyrolysis to convert PCS into a bifunctional material for the adsorption of heavy metal and the activation of peroxymonosulfate (PMS) oxidation. Adsorption isotherm and kinetic model fitting by Langmuir and pseudo-second-order well clarified the adsorption capacity and behavior of carbonized soil (CS) loaded with sulfur and iron (FeS@CS) for heavy metals. The theoretic maximum adsorption capacities of Pb2+, Cu2+, Cd2+, and Zn2+ by Langmuir model were 415.40, 80.25, 61.55, and 30.90 mg/g, respectively. The main adsorption mechanism includes sulfide precipitation, co-precipitation and surface complexation by iron oxides, and complexation by oxygen-containing functional groups. When the dosage of FeS@CS and PMS were both 3 g/L, the removal rate of aniline reached 99.64 % in 6 h. After five cycles of reuse, the aniline degradation rate was still as high as 93.14 %. The non-free radical pathway dominated in CS/PMS and FeS@CS/PMS systems. The electron hole was the primary active species in the CS/PMS system, which promoted aniline degradation by accelerating direct electron transfer. In comparison with CS, the surface of FeS@CS contained more iron oxides, oxygen-containing functional groups, and oxygen vacancies, making 1O2 the primary active species in the FeS@CS/PMS system. This study proposed a new integrated strategy for the efficient remediation of PCS and value-added reutilization of remediated soil.

Longitudinal Variations in the tprK Gene of Treponema pallidum in an Amoy Strain-Infected Rabbit Model.

Heterogeneous tprK sequences have been hypothesized to be an important factor for persistent infection of Treponema pallidum subsp. pallidum (T. pallidum) in humans. Previous research has only explored tprK diversity using a rabbit model infected with almost clonal isolates, which is inconsistent with the fact that infected human isolates contain multiple heterogeneous tprK sequences. Here, we used the T. pallidum Amoy strain with heterogeneous tprK sequences to establish a rabbit infection model and explore longitudinal variations in the tprK gene under normal infection, immunosuppression treatment, and benzathine penicillin G (BPG) treatment using next-generation sequencing. The diversity of the tprK gene was high in all three groups but was highest in the control group and lowest in the BPG group. Interestingly, the overall diversity of tprK in all three groups decreased during infection, exhibiting a "more to less" trend, indicating that survival selection may be an important factor affecting tprK variation in the later infection stage. BPG treatment appeared to reduce the diversity of tprK but increased the frequency of predominant sequence changes, which might facilitate the escape of T. pallidum from the host immune clearance. Furthermore, the original predominant V region sequence did not disappear with disease progression but retained a relatively high proportion within the population, suggesting a new direction for tprK-related vaccine research. This study provides insights into longitudinal variations within the highly heterogeneous tprK gene sequences of T. pallidum and will contribute to further exploration of the pathogenesis of syphilis. IMPORTANCE The tprK variations are an important factor in persistent T. pallidum infection. A nearly clonal isolate has been used previously to investigate the mechanism of tprK gene variations; however, clinical T. pallidum isolates in infected humans exhibit multiple heterogeneous tprK sequences. Here, we use next-generation sequencing to explore longitudinal variations in the tprK gene under normal infection and immunosuppression and benzathine penicillin G treatment in a rabbit model infected with the Amoy strain with heterogeneous tprK sequences. The overall diversity of tprK in all three groups was high and decreased during infection, exhibiting a "more to less" trend. Benzathine penicillin G treatment reduced the diversity of tprK but increased the frequency of predominant sequence changes. Moreover, the original predominant V region sequence did not disappear as the disease progressed but remained at a relatively high proportion within the population. The research results give us a new understanding about tprK variation.

Genetic Profiling of the Full-Length tprK Gene in Patients with Primary and Secondary Syphilis.

TprK antigenic variation is acknowledged as an important strategy developed by Treponema pallidum to achieve immune evasion. Previous studies applied short-read sequencing to explore tprK gene sequence diversity in clinical samples; however, due to the limitations of short-read sequencing, it was difficult to determine the linkage between the seven V regions, and crucial information about full-length tprK variants was lost. Although two recent studies explored complete tprK gene profiles in natural human syphilis infection, there are still too few profiled full-length tprK variants among clinical T. pallidum isolates to fully understand the characteristics of TprK coding diversity. Here, Pacific Biosciences (PacBio) long-read sequencing was applied to examine the diversity of full-length tprK variants in 21 clinical T. pallidum isolates from 11 patients with primary syphilis and 10 patients with secondary syphilis. A total of 398 high-confidence full-length sequences, which presented remarkable sequence heterogeneity, were found. However, these full-length tprK variants exhibited limited variation in length and GC content, showing 24 length types and average GC content of 51.5 ± 0.42% and 51.6 ± 0.26% for primary and secondary syphilis samples, respectively. Additionally, the combined patterns of mutated V regions generating new tprK variants were obviously different in primary and secondary syphilis samples. The diversity of tprK gene sequences in primary syphilis samples may represent the underlying variability of the bacterium; conversely, the variability of the tprK gene in secondary syphilis samples may more accurately reflect how T. pallidum escapes host immune clearance. These data highlight the tprK gene as an important coding gene that shows conflicting genetic characteristics but underlies the persistence of spirochete infection. IMPORTANCE The resurgence of syphilis in both low- and high-income countries has attracted attention, and persistent infection by the pathogen has long been a research focus. The tprK gene, encoding the hypervariable outer membrane protein, is thought to be responsible for pathogen immune evasion and persistent infection. Here, PacBio long-read sequencing was applied to examine the diversity of full-length tprK variants in 21 clinical T. pallidum isolates from 11 patients with primary syphilis and 10 patients with secondary syphilis. The results showed that the sequences of the tprK gene were remarkably heterogeneous; however, the sequences presented limited variation in length and GC content. The investigation of the combined patterns of the V regions allowed us to gain insight into the features of the tprK gene generating new variants at different clinical stages. The findings of this study will be helpful for further exploration of the pathogenesis of syphilis.

Response and duration of serum anti-SARS-CoV-2 antibodies induced by the third dose of an inactivated vaccine: A prospective longitudinal cohort study at 21 serial time points over 641 days.

Given the prevalence of low-pathogenic but highly infectious Omicron variants, a cohort study was conducted to assess the response and duration of novel coronavirus-inactivated vaccine-induced antibodies 1 year after the third dose (Day 641). Blood samples were collected and anti-spike neutralizing antibodies (neutralizing antibody), total antibodies against the receptor-binding domain of the spike protein (total antibody), and immunoglobulin G antibodies against the spike protein (IgG antibody) were determined. Antibody kinetics and attenuation were evaluated. The results showed that the levels of neutralizing, total, and IgG antibodies on Day 641 were 98.05 IU/mL, 152.8 AU/mL, and 7.68 S/CO, respectively. Levels of anti-SARS-CoV-2 antibodies were higher in the younger subgroup than in the older subgroup at several time points after the second and third doses. The seropositive rate of neutralizing antibodies providing protection from infection or severe infection was 46.87% and 87.5%, and the seropositive rates of total antibody and IgG antibody were maintained at 100% and 90.63%, respectively. The half-lives of neutralizing, total, and IgG antibodies were 186.89, 363.04, and 417.50 days, respectively. Collectively, anti-SARS-CoV-2 antibodies may provide a certain degree of protection from infection 1 year after the third dose and high protection from severe infection.

Serum Ubiquitin C-Terminal Hydrolase-L1, Glial Fibrillary Acidic Protein, and Neurofilament Light Chain Are Good Entry Points and Biomarker Candidates for Neurosyphilis Diagnosis Among Patients Without Human Immunodeficiency Virus to Avoid Lumbar Puncture.

BACKGROUND: Laboratory tests to diagnose neurosyphilis using cerebrospinal fluid (CSF) are currently disadvantageous as a lumbar puncture is required, which may result in patients with neurosyphilis missing an opportunity for early diagnosis. Thus, blood biomarker candidates that are more convenient and minimally invasive to collect for diagnosing neurosyphilis is urgently needed. METHODS: This observational study aimed to analyze serum ubiquitin C-terminal hydrolase-L1 (UCH-L1), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NF-L) levels in 153 patients without human immunodeficiency virus (HIV) and to evaluate their diagnostic performance in neurosyphilis compared with CSF. RESULTS: Serum UCH-L1, GFAP, and NF-L levels were significantly higher in patients with neurosyphilis compared with patients with uncomplicated syphilis or non-syphilis. For the diagnosis of neurosyphilis, serum UCH-L1, GFAP, and NF-L revealed sensitivities of 90.20%, 80.40%, and 88.24%, and specificities of 92.16%, 78.43%, and 80.39%, respectively, at cutoff levels of 814.50 pg/mL, 442.70 pg/mL, and 45.19 pg/mL, respectively. In patients with syphilis, serum UCH-L1, GFAP, and NF-L levels correlated strongly or moderately with those in the CSF, with similar or better diagnostic performance than those in the CSF. The testing algorithms' sensitivity and specificity increased to 98.04% and 96.08%, respectively, when subjected to parallel and combination testing, respectively. CONCLUSIONS: To avoid lumbar puncture, each serum UCH-L1, GFAP, and NF-L is a good entry point and biomarker candidate for the diagnosis of neurosyphilis among patients without HIV. These proteins used in concerto can further improve the diagnostic sensitivity and specificity.

Development and Evaluation of a Novel One-Step RT-qPCR Targeting the Vero Gene for the Identification of False-Positive Results Caused by Inactivated Virus Vaccine Contamination.

To identify false-positive SARS-CoV-2 test results caused by novel coronavirus inactivated vaccine contamination, a novel RT-qPCR targeting the ORF1ab and N genes of SARS-CoV-2 and Vero gene was developed. The amplification efficiency, precision, and lower limit of detection (LLOD) of the RT-qPCR assay were determined. A total of 346 clinical samples and 132 environmental samples were assessed, and the diagnostic performance was evaluated. The results showed that the amplification efficiency of the ORF1ab, N, and Vero genes was 95%, 97%, and 93%, respectively. The coefficients of variation of Ct values at a concentration of 3 × 104 copies/mL were lower than 5%. The LLOD for the ORF1ab, N, and Vero genes reached 8.0, 3.3, and 8.2 copies/reaction, respectively. For the 346 clinical samples, our RT-qPCR assay identified SARS-CoV-2-positive and SARS-CoV-2-negative samples with a sensitivity of 100.00% and a specificity of 99.30% and novel coronavirus inactivated vaccine-contaminated samples with a sensitivity of 100% and a specificity of 100%. For the environmental samples, our RT-qPCR assay identified novel coronavirus inactivated vaccine-contaminated samples with a sensitivity of 88.06% and a specificity of 95.38%. In conclusion, the RT-qPCR assay we established can be used to diagnose COVID-19 and, to a certain extent, false-positive results due to vaccine contamination.

Anti-SARS-CoV-2 IgM Secondary Response Was Suppressed by Preexisting Immunity in Vaccinees: A Prospective, Longitudinal Cohort Study over 456 Days.

To obtain more insight into IgM in anti-SARS-CoV-2 immunity a prospective cohort study was carried out in 32 volunteers to longitudinally profile the kinetics of the anti-SARS-CoV-2 IgM response induced by administration of a three-dose inactivated SARS-CoV-2 vaccine regimen at 19 serial time points over 456 days. The first and second doses were considered primary immunization, while the third dose was considered secondary immunization. IgM antibodies showed a low secondary response that was different from the other three antibodies (neutralizing, total, and IgG antibodies). There were 31.25% (10/32) (95% CI, 14.30-48.20%) of participants who never achieved a positive IgM antibody conversion over 456 days after vaccination. The seropositivity rate of IgM antibodies was 68.75% (22/32) (95% CI, 51.80-85.70%) after primary immunization. Unexpectedly, after secondary immunization the seropositivity response rate was only 9.38% (3/32) (95% CI, 1.30-20.10%), which was much lower than that after primary immunization (p = 0.000). Spearman's correlation analysis indicated a poor correlation of IgM antibodies with the other three antibodies. IgM response in vaccinees was completely different from the response patterns of neutralizing, total, and IgG antibodies following both the primary immunization and the secondary immunization and was suppressed by pre-existing immunity induced by primary immunization.

Evaluation of cerebrospinal fluid ubiquitin C-terminal hydrolase-L1, glial fibrillary acidic protein, and neurofilament light protein as novel markers for the diagnosis of neurosyphilis among HIV-negative patients.

OBJECTIVES: To evaluate the possibility of using cerebrospinal fluid (CSF) ubiquitin C-terminal hydrolase L1 (UCH-L1), glial fibrillary acidic protein (GFAP), and neurofilament light protein (NF-L) for the diagnosis of neurosyphilis (NS). METHODS: A cross-sectional study of 576 subjects was conducted at Zhongshan Hospital from January 2021 to August 2022 to evaluate the diagnostic accuracy of CSF UCH-L1, GFAP, and NF-L for NS and analyze their correlations with CSF rapid plasma reagin (RPR), white blood cells (WBCs), and protein. RESULTS: Patients with NS had higher CSF UCH-L1, GFAP, and NF-L levels than patients with syphilis/non-NS and nonsyphilis. Using a cut-off point of 652.25 pg/ml, 548.89 pg/ml, and 48.38 pg/ml, CSF UCH-L1, GFAP, and NF-L had a sensitivity of 85.11%, 76.60%, and 82.98%, with a specificity of 92.22%, 85.56%, and 91.11%, respectively, for NS diagnosis. Moreover, parallel and serial testing algorithms improved their sensitivity and specificity to 93.62% and 98.89%, respectively. Interestingly, levels between patients with NS who are CSF RPR-positive and -negative did not differ and showed a weak or moderate correlation with WBC and CSF protein in patients with syphilis. CONCLUSION: CSF UCH-L1, GFAP, and NF-L can be used as novel markers for the diagnosis of NS, independent of CSF RPR, WBC, and proteins.

Evaluating the value of anti-SARS-CoV-2 antibody detection and neutralizing responses with euvirus: A population of 10776 close contacts in the epidemic of Fujian.

BACKGROUND: Nucleic acid detection represents limitations due to its false-negative rate and technical complexity in the COVID-19 pandemic. Anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody tests are widely spread all over the world presently. However, there is no report on the effectiveness of anti-SARS-CoV-2 antibody testing methods in China. METHODS: We gathered 10776 serum samples from close contacts of the SARS-CoV-2 infections in Fujian of China and used 2 chemiluminescence immunoassays (Wantai Bio., Yahuilong Bio.) and 2 lateral flow immunoassays (Lizhu Bio. and Dongfang Bio.) to perform the anti-SARS-CoV-2 antibody tests in China. RESULTS: The 4 antibody tests have great diagnostic value for infected or uninfected, especially in the neutralizing antibodies tests, the AUC can reach 0.939 (Wantai Bio.) and 0.916 (Yahuilong Bio.). Furthermore, we used pseudoviruses and euvirus neutralization assay to validate the effectiveness of these antibody test, the results of pseudoviruses neutralization assay or euvirus neutralization assay shows a considerable correlation with the 4 antibody detection respectively, particularly in euvirus neutralization assay, neutralizing antibodies detected by Wantai Bio. or Yahuilong Bio., the correlation can get the level of 0.93 or 0.82. CONCLUSIONS: The findings of this study demonstrate that the detections of antibodies have profound value in the diagnosis of COVID-19.

Effectiveness of SARS-CoV-2-inactivated vaccine and the correlation to neutralizing antibodies: A test-negative case-control study.

Severe acute respiratory syndrome coronavirus 2 breakthrough infection in highly vaccinated populations raises study on the effectiveness for inactivated vaccine, including effectiveness of the vaccine dose, the continuance of effectiveness, the effectiveness against severe/critical coronavirus disease 2019 and against secondary attacks. A population of 10 870 close contacts were investigated in a Delta variant's epidemic. The effectiveness of vaccination was estimated in a test-negative case-control study. In addition, serum was used to detect neutralizing antibodies, to explore their correlation to effectiveness. The vaccine effectiveness (VE) values were estimated for populations aged 12 years or older. The overall adjusted VE was 56.2% and a two-dose vaccine was more effective than a one-dose vaccine (56.7% vs. 43.8%). In addition, the population that got the second dose vaccine within 2 months showed higher VE than the population vaccinated for longer than 2 months (61.5% vs. 52.3%). Among the population who vaccinated 2 doses or within 2 months, a higher level of neutralizing antibodies was observed. For infected cases, vaccinated populations showed lower rates of transmission (2.63% vs. 4.36%). Further, those vaccinated cases, who were not found causing transmission, had a higher level of antibodies. The study provided a full view of the effectiveness of inactivated vaccines in a real-world setting. The time-related VE against infection and lower transmission of breakthrough vaccinated cases were observed, which may indicate that a necessity of a booster vaccine to maintain the effectiveness and high level of neutralizing antibody.