IgM-specific linear epitopes on the E2 protein for serodiagnosis of Chikungunya.

Chikungunya virus (CHIKV) and Dengue virus (DENV) are vector-borne diseases transmitted by Aedes aegypti and Aedes albopictus that pose a significant threat to global public health. Cases of acute Chikungunya fever often present similar clinical symptoms to other vector-borne diseases, such as Dengue fever. In regions where multiple vector-borne diseases coexist, CHIKV is often overlooked or misdiagnosed as Dengue virus, West Nile virus, Zika virus or other viral infections, which delays its prevention and control. However, IgM antibodies directed against the E2 protein of CHIKV have not yet been generalized to clinical settings due to the low sensitivity and high cost in commercial kits. Indirect ELISA with peptides provides an effective supplementary tool for detecting CHIKV IgM antibodies. Our study aims at examining the potential of linear epitopes on the E2 glycoprotein that specifically bind to IgM antibodies as serodiagnostic tool for CHIKV. The sensitivity of the established peptide indirect ELISA method for detecting clinical samples is significantly better than that of commercial kits, realizing a beneficial supplement to the existing IgM antibody assay. It also established the groundwork for comprehending the biological mechanisms of the CHIKV E2 protein and the advancement of innovative epitope peptide vaccines.

Association between toxoplasmosis and autoimmune rheumatic diseases in Egyptian patients.

PURPOSE: To explore the association between T. gondii and autoimmune rheumatic diseases (ARDs). METHODS: This study involved 82 patients with ARDs: 44 rheumatoid arthritis (RA), 28 systemic lupus erythematosus (SLE), and 10 systemic sclerosis (SSc) and 61 age- and sex-matched controls. Sociodemographic, clinical, and laboratory data were collected, and disease activity was assessed. Exposure to toxoplasmosis risk factors was investigated. Serological tests for anti-Toxoplasma IgM and IgG antibodies were assessed using ELISA. RESULTS: In SLE patients, a significant difference of T. gondii IgM versus controls was detected (P=.03). In RA and SLE patients, T. gondii IgG showed a significant difference versus controls (34 (77.3%) P=.001 and 18 (64.3%) P=.03, respectively). There was no significant difference in SSc versus controls. Fetal congenital anomalies displayed a significant difference in IgM seropositive compared to seronegative patients (P=.04). Cat exposure showed a significant difference between IgM and IgG seropositive versus seronegative patients (12 (80.0%) P=.02 and 34 (59.6) P=.04, respectively). There was no significant difference in seropositive patients regarding history of abortion, neuro-psychiatric manifestations, disease activity parameters (ESR, CRP), or different regimens of medications. CONCLUSION: Toxoplasma IgM seropositivity is associated with SLE patients. T. gondii IgG seropositivity is associated with both RA and SLE patients. However, Toxoplasma seropositivity had no association with SSc patients. An association between fetal congenital anomalies and IgM seropositivity was demonstrated. A linkage between cat exposure as a risk factor and toxoplasmosis was suggested among ARD patiants. Exploration of impact of toxoplasmosis on ARDs is a necessity through randomized controlled trials.

Association between toxoplasmosis and autoimmune rheumatic diseases in Egyptian patients / Asociación entre toxoplasmosis y enfermedades reumáticas autoinmunes en pacientes egipcios

Purpose: To explore the association between T. gondii and autoimmune rheumatic diseases (ARDs). Methods: This study involved 82 patients with ARDs: 44 rheumatoid arthritis (RA), 28 systemic lupus erythematosus (SLE), and 10 systemic sclerosis (SSc) and 61 age- and sex-matched controls. Sociodemographic, clinical, and laboratory data were collected, and disease activity was assessed. Exposure to toxoplasmosis risk factors was investigated. Serological tests for anti-Toxoplasma IgM and IgG antibodies were assessed using ELISA. Results: In SLE patients, a significant difference of T. gondii IgM versus controls was detected (P=.03). In RA and SLE patients, T. gondii IgG showed a significant difference versus controls (34 (77.3%) P=.001 and 18 (64.3%) P=.03, respectively). There was no significant difference in SSc versus controls. Fetal congenital anomalies displayed a significant difference in IgM seropositive compared to seronegative patients (P=.04). Cat exposure showed a significant difference between IgM and IgG seropositive versus seronegative patients (12 (80.0%) P=.02 and 34 (59.6) P=.04, respectively). There was no significant difference in seropositive patients regarding history of abortion, neuro-psychiatric manifestations, disease activity parameters (ESR, CRP), or different regimens of medications. Conclusion: Toxoplasma IgM seropositivity is associated with SLE patients. T. gondii IgG seropositivity is associated with both RA and SLE patients. However, Toxoplasma seropositivity had no association with SSc patients. An association between fetal congenital anomalies and IgM seropositivity was demonstrated. A linkage between cat exposure as a risk factor and toxoplasmosis was suggested among ARD patiants. Exploration of impact of toxoplasmosis on ARDs is a necessity through randomized controlled trials.(AU)

Propósito: Explorar la asociación entre Toxoplasma gondii y enfermedades reumáticas autoinmunes (ERA).Métodos: Este estudio involucró a 82 pacientes con ERA: 44 con artritis reumatoide (AR), 28 con lupus eritematoso sistémico (LES) y 10 con esclerosis sistémica (SSc); y 61 controles emparejados por edad y sexo. Se recopilaron datos sociodemográficos, clínicos y de laboratorio, y se evaluó la actividad de la enfermedad. Se indagó exposición a factores de riesgo de toxoplasmosis. Las pruebas serológicas de anticuerpos IgM e IgG antitoxoplasma se evaluaron mediante ELISA.Resultados: En pacientes con LES se detectó una diferencia significativa de T. gondii IgM vs. controles (p = 0,03). En pacientes con AR y LES, T. gondii IgG mostró una diferencia significativa frente a los controles (34 [77,3%] p = 0,001 y 18 [64,3%] p = 0,03, respectivamente). No hay diferencia significativa en SSc vs. controles. Las anomalías congénitas fetales mostraron una diferencia significativa en los pacientes seropositivos para IgM en comparación con los pacientes seronegativos (p = 0,04). La exposición a los gatos mostró una diferencia significativa entre los pacientes seropositivos para IgM e IgG frente a los seronegativos (12 [80%] p = 0,02 y 34 [59,6] p = 0,04, respectivamente). No hubo diferencias significativas en pacientes seropositivos con respecto a antecedentes de aborto, manifestaciones neuropsiquiátricas, parámetros de actividad de la enfermedad (ESR, CRP) o diferentes regímenes de medicamentos.(AU)

[Preparation of HSV-IgM human-mouse chimeric antibody and development of stable recombinant cell line].

In order to achieve large-scale production of HSV-IgM (HSV1, HSV2) human-mouse chimeric antibody in vitro, the gene sequence of the corresponding hybridoma cell was harvested by RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) technique to clone the chimeric antibody into eukaryotic expression vectors, and express the target proteins in CHO-S cells. At the same time, the screening process of stable cell lines was optimized, and the pressure conditions of pool construction stage and monoclonal screening stage were explored. Finally, the target protein was purified by protein L affinity purification method and the biological activity was detected. The recombinant IgM antibodies, HSV1 and HSV2, weighted at 899 kDa and 909 kDa respectively, were prepared. The optimal screening pressure was 20P200M (the first phase of pressure) and 50P1000M (the second phase of pressure). The final titer for the monoclonal expression of HSV1-IgM and HSV2-IgM was 1 620 mg/L and 623 mg/L, respectively. This study may facilitate the development of quality control products of HSV1 and HSV2 IgM series recombinant antibodies as well as efficient expression of IgM subtype antibodies in vitro.

Ginsenoside Rg3 endows liposomes with prolonged blood circulation and reduced accelerated blood clearance.

PEGylated cholesterol-containing liposomes (Chol-PEG-lipo) have been widely used as a drug carrier for their good stealth property in blood circulation where cholesterol maintains the stability of the liposomal lipid bilayer and PEGylation endows liposomes with long circulation capability. However, cholesterol-related disadvantages and the accelerated blood clearance (ABC) phenomenon caused by PEGylation greatly limit the application of conventional stealth liposomes in clinic. Herein, ginsenoside Rg3 was selected to substitute cholesterol and PEG for liposomes preparation (Rg3-lipo). Rg3 was proved with similar liposomal membrane regulation ability to cholesterol and comparable long circulation effect to PEG. In addition, repeated administrations of Chol-PEG-lipo and Rg3-lipo were performed. The circulation time of the second dose of Chol-PEG-lipo was substantially reduced accompanied by a greatly increased accumulation in the liver due to the induction of anti-PEG IgM and the subsequent activated complement system. In contrast, no significantly increased level of relative plasma cells, IgM secretion and the complement activation in blood circulation was observed after the second injection of Rg3-lipo. As a result, Rg3-lipo showed great stealth property without ABC phenomenon. Therefore, developing liposomes utilizing Rg3 instead of PEG and cholesterol presents a promising strategy to prolong the blood circulation time of liposomes without triggering the ABC phenomenon and activated immune responses.

Renin-angiotensin-system blockers and IgG antibodies in end-stage renal disease hemodialysis-receiving patients diagnosed with COVID-19 infection.

OBJECTIVES: To evaluate the prevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections among patients receiving in-center hemodialysis (ICHD), the relationship between the IgG antibody levels against the virus and SARS-CoV-2-associated symptoms, hemodialysis adequacy, and the antihypertensives used in order to control blood pressure. METHODS: A prospective observational study was carried out at a tertiary care center, King Fahad Kidney Center, Riyadh, Kingdom of Saudi Arabia, between November 2020 and January 2021. A total of 214 ICHD patients with end-stage renal disease (ESRD) were included, and the levels of their anti-SARS-CoV-2 IgG antibodies were assessed after obtaining their informed consent. RESULTS: Our tests indicated that 15% of the patients in the study's population had detectable SARS-CoV-2 IgG antibodies, with more than half of them (53%) being asymptomatic. We also found that ESRD patients on angiotensin converting enzyme inhibitors or angiotensin receptor blockers (ACEIs/ARBs) had higher levels of SARS-CoV-2 IgG antibodies than patients not receiving this group of medications. CONCLUSION: More studies are required to assess whether patients with a SARS-CoV-2 infection that do not have an indication for being prescribed ACEIs/ARBs would benefit from receiving these medications.

Anti-Nipah Virus Enzyme-Linked Immunosorbent Assays with Non-human Primate and Hamster Serum.

Enzyme-linked Immunosorbent assays or ELISAs are a versatile method for detecting various immunological ligands of interest. As the name suggests, ELISAs rely on the interaction between a ligand and an antibody to produce results. In the study of infectious disease, ELISAs are commonly used to determine if a pathogen-specific immune response has occurred in a host organism. These assays can be performed in serosurveys as part of epidemiological investigations during, or following, an infectious disease outbreak. In the research environment, ELISAs are used to quantify the humoral immune response following infection or vaccination of a host organism. Data from these assays can be used to determine the type of immune response elicited (e.g. IgG1 vs IgG2) and the robustness of the response. Here, we describe ELISAs that were developed for the study of either hamsters or non-human primates vaccinated against Nipah virus infection, or infected with Nipah virus. The ELISAs described include assays for both IgG and IgM in the hamster and non-human primate models for Nipah virus-induced disease. An assay was also developed for the detection of IgA in bronchoalveolar lavage from non-human primates.

[Delayed Blood Transfusion Adverse Reactions Caused by Hypothermia Cardiopulmonary Bypass and Its Coping Strategies].

OBJECTIVE: To investigate a case of delayed hemolytic transfusion reaction (DHTR), and find the reason and coping strategies to prevent similar incidents in the future. METHODS: Relative antibody identification was carried out, suitable erythrocytes was screened, and relevant indicators after transfusion were evaluated. Medical record and laboratory report of the patient were reviewed, the cause was analyzed, and corresponding treatment was carried out. RESULTS: The patient suffered from DHTR caused by IgM anti-M antibody and low body temperature cardiopulmonary bypass. After anti-hemolytic treatment, the patient was gradually improved, the bilirubin gradually decreased, and finally cured and discharged. CONCLUSION: When the transfusion department finds any antibodies which have activity at room temperature but no respond at 37 ℃, they should communicate with clinical medical staff in time. Warm transfusion should be used during blood transfusion to prevent transfusion-related hemolytic reaction.

Revision of Cytomegalovirus Immunoglobulin M Antibody Titer Cutoff in a Maternal Antibody Screening Program in Japan: A Cohort Comparison Involving a Total of 32,000 Pregnant Women.

Cytomegalovirus (CMV) is associated with congenital infections. We aimed to validate the revised CMV immunoglobulin (Ig) M titer cutoff for IgG avidity measurements as a reflex test in maternal screening to identify women with primary CMV infection and newborn congenital cytomegalovirus (cCMV). We screened maternal CMV antibodies (the Denka assay) in Japan, from 2017 to 2019, using a revised IgM cutoff (≥4.00 index). Participants were tested for IgG and IgM antibodies, and for IgG avidity if IgM levels exceeded the cutoff. We compared these with corresponding results from 2013 to 2017 based on the original cutoff (≥1.21) and recalculated using the revised cutoff. Newborn urine CMV DNA tests were performed for women with low avidity (≤35.0%). Among 12,832 women screened in 2017-2019, 127 (1.0%) had IgM above the revised cutoff. Thirty-five exhibited low avidity, and seven infants developed cCMV. Of 19,435 women screened in 2013-2017, 184 (1.0%) had IgM above the revised cutoff, 67 had low avidity, and 1 had cCMV. The 2017-2019 results were not significantly different from the 2013-2017 results. The revised IgM cutoff improves maternal screening in identifying primary infection and newborn cCMV; however, further study related to other assays than Denka is required.

Poor accuracy of single serological IgM tests in children with suspected acute Mycoplasma pneumoniae infection in Guangzhou, China.

Introduction. Early and accurate diagnosis of Mycoplasma pneumoniae (MP) infection of children with pneumonia is at the core of treatment in clinical practice.Gap Statement. Serological immunoglobulin M (IgM) tests for MP infection of children in south China have been rarely described.Aim. To assess the diagnostic performance and clinical application of serodiagnosis of MP infection in paediatric pneumonia patients.Methodology. Serum samples from 144 children diagnosed with MP pneumonia were subjected to a particle agglutination (PA)-based IgM assay. Meanwhile, we used an established suspension array as the reference standard method for the detection of MP DNA in bronchoalveolar lavage fluid (BALF) from all patients to assess the reliability of serological assays.Results. When running immunological testing in single serum samples, 80.6 %(79/98) of cases were diagnosed with MP infection, whereas only 55 (56.1 %) cases were positive in MP DNA analysis. Furthermore, single serum tests for IgM during acute MP infection resulted in 85.5 % (47/55) sensitivity and 25.6 % (11/43) specificity. Nevertheless, immunological testing and MP DNA analysis yielded the same results when paired sera were available for MP IgM antibody testing.Conclusion. Paired serological IgM assays are necessary for the determination of an acute MP infection, whereas single serological IgM testing is unreliable. Moreover, even a short interval of two MP serological tests works well.

Molecular-based study of scrub typhus in Kerala, South India from 2014 to 2021: a laboratory-based study.

Scrub typhus (ST) is a neglected acute, febrile, infectious disease caused by the intracellular parasite Orientia tsutsugamushi, a gram-negative coccobacillus of the family Rickettsiaceae. Early and precise diagnosis is crucial to reduce the risk of developing disease complications. However, IgM antibody enzyme-linked immunosorbent assay (IgM ELISA) and indirect immunofluorescence assay (IFA) remain essential for diagnosis. However, it could be more helpful for early diagnosis due to the need for uniformity of approach in the diagnostic accuracy studies to determine appropriate ELISA cut-offs for various geographic locations. Hence, we aim to study the O. tsutsugamushi type-specific 56 kilodalton (kDa) protein gene using nested PCR (nPCR) and DNA sequence analysis as a molecular marker for early diagnosis. Out of 10,439 suspected cases, 1147/10,439 (11%) patients were positive for IgM ELISA. A total of 1044/10,439 (10%) samples were randomly tested after nPCR and compared with IgM ELISA results and DNA sequence analysis. Using nested PCR and IgM ELISA methods, 13% (134/1044) and 12% (125/1044) of the samples were positive, respectively. The serology method could not replicate the substantial number of positive cases demonstrated by nPCR; therefore, significant mutual exclusivity of the two techniques requires further investigation. Furthermore, our phylogenetic analysis revealed a clustering of isolates with Karp-related strains, providing insight into the transmission dynamics. Therefore, molecular diagnostic methods may aid in the early diagnosis of infection and enable prompt treatment of ST in endemic regions. Our results show that IgM ELISA can provide complete diagnostic advantages in conjunction with nPCR and can be an essential tool for accurate diagnosis. In addition, the DNA sequencing analysis of the samples showed that Karp-related strains were the main strains. Furthermore, research with samples from various regions in combination with the entire genome sequencing of O. tsutsugamushi is required to understand the infection mechanism better and develop robust early detection methods. Supplementary Information: The online version contains supplementary material available at 10.1007/s00580-023-03443-8.

Anti-SARS-CoV-2 spike immunoglobulin G and immunoglobulin M titers decline as interval from the second inactivated vaccine dose to the onset of illness is prolonged in breakthrough infection patients.

BACKGROUND: Understanding of the early immune response in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infections is limited. METHODS: Ninety-eight patients with coronavirus disease 2019 (COVID-19) breakthrough infections were divided into two groups, with intervals from receiving the second dose of inactivated vaccine to the onset of illness <60 or ≥60 days. RESULTS: The median lymphocyte count and the median anti-SARS-CoV-2 spike immunoglobulin G (IgG) and immunoglobulin M (IgM) titers were higher in the <60-day interval group compared with the corresponding medians in the ≥60-day interval group (p = 0.005, p = 0.001, and p = 0.001, respectively). The median interleukin-6 (IL-6) level in the <60-day interval group was significantly lower than the median IL-6 level in the ≥60-day interval group (p < 0.001). CONCLUSIONS: Our results highlight the different anti-SARS-CoV-2 spike IgG and IgM antibody titers among patients with different intervals from receiving the second dose of inactivated vaccine to the onset of illness.

Dual blockages of a broad and potent neutralizing IgM antibody targeting GH loop of EV-As.

The reported enterovirus A 71 (EVA71) vaccines and immunoglobin G (IgG) antibodies have no cross-antiviral efficacy against other enterovirus A (EV-A) which caused hand, foot and mouth disease (HFMD). Here we constructed an IgM antibody (20-IgM) based on our previous discovery to address the resistance encountered by IgG-based immunotherapy. Although binding to the same conserved neutralizing epitope within the GH loop of EV-As VP1, the antiviral breath and potency of 20-IgM are still higher than its parental 20-IgG1. The 20-IgM blocks the interaction between the EV-As and its receptors, scavenger receptor class B, member 2 (SCARB2) and Kringle-containing transmembrane protein 1(KREMEN1) of the host cell. The 20-IgM also neutralizes the EV-As at the post-attachment stages, including postattachment neutralization, uncoating and RNA release inhibition after internalization. Mechanistically, the dual blockage effect of 20-IgM is dependent on both a conserved site targeting and high affinity binding. Meanwhile, 20-IgM provides cross-antiviral efficacy in EV-As orally infected neonatal ICR mice. Collectively, 20-IgM and its property exhibit excellent antiviral activity with a dual-blockage inhibitory effect at both the pre- and post-attachment stages. The finding enhances our understanding of IgM-mediated immunity and highlights the potential of IgM subtype antibodies against enterovirus infections.

Seroprevalence and geographical distribution of parvovirus B19 antibodies in pregnant women: A-meta analysis.

Parvovirus B19 has been identified to infect pregnant women and cause anemia, spontaneous abortion, and fetal death. Given the significance of parvovirus B19 complications, this study aims to determine the seroprevalence and geographical distribution of parvovirus B19 antibodies in pregnant women to improve health control policies in the community. Online international databases and national Persian databases were used to define appropriate studies published between 2000 and January 2021. The quality of all papers was determined by a Newcastle-Ottawa Scale (NOS) checklist. The statistical analyses were performed using the Stata version 11 package (StataCorp, College Station, TX, USA) software. Heterogeneity among the primary studies was calculated using Cochran's Q-test and I2 index. The Egger test and the funnel plot chart with a significance level of less than 0.1 were used to evaluate the publishing bias. The seroprevalence of parvovirus B19 IgG antibodies among pregnant and non-pregnant women in Iran was assessed in 12 primary studies. Our finding showed that the seroprevalence of parvovirus B19 IgG antibodies among pregnant women varies from 21% to 76%. Combining the results of 5 primary studies based on the random effect model, the seroprevalence of parvovirus B19 IgG antibody among pregnant women in Iran was estimated to be 54% (95% CI:33-76). The seroprevalence of parvovirus B19 IgM antibodies has been reported in 9 studies. By combining the results of these studies using a random effect model, the seroprevalence of parvovirus B19 IgM antibody among pregnant women was estimated to be 3% (95% CI: 1-6). Generally, it is suggested that appropriate screening programs should be performed for the treatment and prevention of diseases. According to this point, the prevalence of parvovirus B19 is low among pregnant women, but it can cause serious manifestations such as hydrops fetalis and severe anemia, therefore, antibody determination using ELISA can be recommended for all pregnant women.

Two pan-SARS-CoV-2 nanobodies and their multivalent derivatives effectively prevent Omicron infections in mice.

With the widespread vaccinations against coronavirus disease 2019 (COVID-19), we are witnessing gradually waning neutralizing antibodies and increasing cases of breakthrough infections, necessitating the development of drugs aside from vaccines, particularly ones that can be administered outside of hospitals. Here, we present two cross-reactive nanobodies (R14 and S43) and their multivalent derivatives, including decameric ones (fused to the immunoglobulin M [IgM] Fc) that maintain potent neutralizing activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after aerosolization and display not only pan-SARS-CoV-2 but also varied pan-sarbecovirus activities. Through respiratory administration to mice, monovalent and decameric R14 significantly reduce the lung viral RNAs at low dose and display potent pre- and post-exposure protection. Furthermore, structural studies reveal the neutralizing mechanisms of R14 and S43 and the multiple inhibition effects that the multivalent derivatives exert. Our work demonstrates promising convenient drug candidates via respiratory administration against SARS-CoV-2 infection, which can contribute to containing the COVID-19 pandemic.

Seroprevalence of Toxoplasma gondii among hemodialysis patients: A possible link to main T-lymphocyte subsets levels and dialysis adequacy.

BACKGROUND: A high prevalence of Toxoplasma gondii infection has been reported in patients with hemodialysis (HD). However, a lack of data exists on the relationship between T lymphocyte subsets and dialysis adequacy. This study aimed to investigate the seroprevalence of Toxoplasma gondii infection among HD patients and its relation to T lymphocyte cells subsets, CD3+, CD4+, CD8+, CD4+/CD8+ ratio, and HD adequacy. METHODS: This cross-sectional comparative study was conducted on 92 subjects. Of them, 42 HD patients and 50 were control participants. Anti-Toxoplasma gondii IgG, IgM antibodies, the T lymphocyte cells subset CD3+, CD4+, CD8+, CD4+/CD8+ ratio, and adequacy of dialysis via calculation of Kt/V were detected for all subjects. RESULTS: The seropositivity for anti-Toxoplasma gondii IgG antibodies was significantly higher in HD patients 66.7% (28/42) compared to 34% in controls (17/50), (p = 0.0003). The main T lymphocyte subsets was significantly lower in HD compared to controls (p < 0.05). Seropositive HD patients exhibited statistically significantly lower T lymphocyte cell subsets and CD4+/CD8+ ratio compared to seronegative patients (p < 0.05). There was a negative correlation between anti-Toxoplasma gondii IgG level and T lymphocyte subsets and the CD4/CD8+ ratio. Binary logistic regression showed that CD4+ T cell significantly predicts Toxoplasma gondii susceptibility among HD patients (p = 0.03). The mean Kt/V index is significantly lower among seropositive HD patients compared to seronegative HD patients (1.05 ± 0.46, 1.41 ± 0.53, respectively, p = 0.03) with a significant negative correlation with anti-Toxoplasma gondii IgG level (p < 0.05). ROC curve analysis showed the CD4+ T cell % had the highest AUC value among HD patients (AUC= 0.88, p < 0.001). The Kt/V value of ≤ 0.8 significantly predicted susceptibility to Toxoplasma gondii infection among HD patients (AUC = 0.68, p = 0.03). CONCLUSION: The current study reinforces previous reports of a high prevalence of Toxoplasma gondii infection among HD patients. CD4+ T cell and Kt/V showed a good diagnostic performance in predicting susceptibility for Toxoplasma gondii infection in HD patients. Considering the clinical consequences caused by Toxoplasma gondii infection in these patients, regular screening and adequate HD are recommended.

Clinical value of 1, 3-β-D glucan and mannan IgM/IgG antibodies in the early diagnosis of invasive candidiasis / 中华微生物学和免疫学杂志

Objective:To evaluate the diagnostic value of 1, 3-β-D glucan (BDG), mannan IgM antibody (Mn-IgM) and mannan IgG antibody (Mn-IgG) in invasive candidiasis and to compare the differences in the diagnostic capability of serological markers used alone or in combination.Methods:Serum samples of 126 patients with invasive candidiasis and 104 healthy people who took physical examination during the same period were collected. BDG was detected by dynamic chromogenic method, and Mn-IgM and Mn-IgG were detected by ELISA. The sensitivity, specificity, positive predictive value, negative predictive value, Youden index, coincidence rate and Kappa value of the three serological markers used alone or in combination in the diagnosis of invasive candidiasis were analyzed and compared. The receiver operating characteristic (ROC) curves were drawn and the areas under the curves (AUCs) were calculated.Results:The levels of BDG, Mn-IgM and Mn-IgG in patients with invasive candidiasis were significantly higher than those in healthy people ( P<0.01). The sensitivity, specificity, Kappa value and AUC of BDG were 48.41%, 92.31%, 0.389 and 0.842. The sensitivity, specificity, Kappa value and AUC of Mn-IgM were 64.29%, 91.35%, 0.540 and 0.829. The sensitivity, specificity, Kappa value and AUC of Mn-IgG were 27.78%, 95.19%, 0.214 and 0.737. The sensitivity, specificity, Kappa value and AUC of BDG+ Mn-IgM were 76.19%, 88.46%, 0.637 and 0.921. The sensitivity, specificity, Kappa value and AUC of BDG+ Mn-IgG were 59.52%, 91.35%, 0.491 and 0.856. The sensitivity, specificity, Kappa value and AUC of Mn-IgM+ Mn-IgG were 69.84%, 90.38%, 0.588 and 0.891. The sensitivity, specificity, Kappa value and AUC of BDG+ Mn-IgM+ Mn-IgG were 80.16%, 88.46%, 0.679 and 0.922. Conclusions:The sensitivity of Mn-IgM was higher than that of BDG and Mn-IgG in the diagnosis of invasive candidiasis. When the serological biomarkers were used in combination, BDG+ Mn-IgM and BDG+ Mn-IgM+ Mn-IgG had relatively high Kappa value and AUC, showing high accuracy. The clinical diagnostic value of multiple serological biomarkers used in combination was significantly higher than that of any serological biomarkers used alone. Early combined detection and continuous monitoring of multiple serological biomarkers in patients with high risk of invasive candidiasis could be used clinically to adjust antifungal treatment strategies timely.

Preparation of HSV-IgM human-mouse chimeric antibody and development of stable recombinant cell line / 生物工程学报

In order to achieve large-scale production of HSV-IgM (HSV1, HSV2) human-mouse chimeric antibody in vitro, the gene sequence of the corresponding hybridoma cell was harvested by RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) technique to clone the chimeric antibody into eukaryotic expression vectors, and express the target proteins in CHO-S cells. At the same time, the screening process of stable cell lines was optimized, and the pressure conditions of pool construction stage and monoclonal screening stage were explored. Finally, the target protein was purified by protein L affinity purification method and the biological activity was detected. The recombinant IgM antibodies, HSV1 and HSV2, weighted at 899 kDa and 909 kDa respectively, were prepared. The optimal screening pressure was 20P200M (the first phase of pressure) and 50P1000M (the second phase of pressure). The final titer for the monoclonal expression of HSV1-IgM and HSV2-IgM was 1 620 mg/L and 623 mg/L, respectively. This study may facilitate the development of quality control products of HSV1 and HSV2 IgM series recombinant antibodies as well as efficient expression of IgM subtype antibodies in vitro.

Results of serum antibody detection from patients with hemorrhagic fever with renal syndrome in Heilongjiang, 2019-2021 / 中国热带医学

@#Abstract: Objective　To detect the antibody levels of hantavirus in serum samples from patients suspected with hemorrhagic fever with renal syndrome (HFRS) in Heilongjiang Province from 2019 to 2021, and to provide scientific basis for the prevention and control of disease. Methods　Enzyme-linked immunosorbent assays (ELISA) were used to detect the IgM antibodies to hantavirus in serum samples collected from suspected patients with HFRS in the acute-phase, and IgM and IgG antibody in convalescent-phase serum samples. The positive rate of IgM antibody in acute-phase serum samples of patients in different years was analyzed with χ2 test by SPSS 19.0, and the data were sorted out and analyzed about patients' gender, occupation, age, date of onset and interval from onset to initial diagnosis by EpiData 3.1, Excel 2003 software. Results　A total of 351 acute-phase serum samples and 208 convalescent-phase serum samples were detected in patients suspected with HFRS, respectively. There were 317 positive IgM antibodies of serum samples in the acute stage, with the positive rate of 90.31%. There was no significant difference in the positive rate of IgM antibodies in the acute stage between different years (χ2=0.895, P=0.639). T The IgM antibodies and IgG antibodies were positive in 32 (15.39%) and 28 (13.46%) of the convalescent-phase serum samples, respectively. Moreover, 148 patients (71.15%) were double-positive for IgM and IgG antibodies at the convalescent stage. The ratio of male to female patients was 4.56∶1, for which male patients were much more than female patients. Occupation was dominated by farmers (253 cases, 79.81%), followed by workers (19 cases, 5.99%) and the unemployed (17 cases, 5.36%), respectively. The age of patients ranged from 10 to 88 years old, with a median age of 49 years old. Most of the patients were in the age group from 30 years old to 60 years old (209 cases, 65.93%), among which the age group from 40 years old to 50 years old (86 cases, 27.13%) had the highest proportion, and the age group from 60 years old to 90 years old had a proportion of 20.18% (19 cases). May and November were the peak periods of HFRS in Heilongjiang Province. The median interval between onset and initial diagnosis was 4 days. Conclusions　There is a gap of about 10% between the clinical diagnosis of HFRS cases and the confirmed cases detected by laboratory in Heilongjiang Province from 2019 to 2021. The virus-specific detection results are important for confirming the diagnosis of local patients with HFRS.

Mechanistic Studies for the Rational Design of Multivalent Glycodendrimers.

We have synthesized B-antigen-displaying dendrimers (16-mers) with different sizes and evaluated their affinity to their IgM antibody in order to investigate which design features lead to effective multivalency. Unexpectedly, the smallest dendrimer, which cannot chelate the multiple binding sites of IgM, clearly exhibited multivalency, together with an affinity similar to or higher than those of the larger dendrimers. These results indicate that the statistical rebinding model, which involves the rapid exchange of clustered glycans, significantly contributes to the multivalency of glycodendrimers. Namely, in the design of glycodendrimers, high-density glycan presentation to enhance statistical rebinding should be considered in addition to the ability to chelate multiple binding sites. This notion stands in contrast to the currently prevailing scientific consensus, which prioritizes the chelation model. This study thus provides new and important guidelines for molecular design of glycodendrimers.