The emerging of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused COVID-19 pandemic. The first case of COVID-19 was reported at early December in 2019 in Wuhan City, China. To examine specific antibodies against SARS-CoV-2 in biological samples before December 2019 would give clues when the epidemic of SARS-CoV-2 might start to circulate in populations. We obtained all 88,517 plasmas from 76,844 blood donors in Wuhan between 1 September and 31 December 2019. We first evaluated the pan-immunoglobin (pan-Ig) against SARS-CoV-2 in 43,850 samples from 32,484 blood donors with suitable sample quality and enough volume. Two hundred and sixty-four samples from 213 donors were pan-Ig reactive, then further tested IgG and IgM, and validated by neutralizing antibodies against SARS-CoV-2. Two hundred and thirteen samples (from 175 donors) were only pan-Ig reactive, 8 (from 4 donors) were pan-Ig and IgG reactive, and 43 (from 34 donors) were pan-Ig and IgM reactive. Microneutralization assay showed all negative results. In addition, 213 screened reactive donors were analyzed and did not show obviously temporal or regional tendency, but the distribution of age showed a difference compared with all tested donors. Then we reviewed SARS-CoV-2 antibody results from these donors who donated several times from September 2019 to June 2020, partly tested in a previous published study, no one was found a significant increase in S/CO of antibodies against SARS-CoV-2. Our findings showed no SARS-CoV-2-specific antibodies existing among blood donors in Wuhan, China before 2020, indicating no evidence of transmission of COVID-19 before December 2019 in Wuhan, China.
Humans ; Antibodies, Viral ; Blood Donors ; China/epidemiology* ; COVID-19/immunology* ; Immunoglobulin G ; Immunoglobulin M ; Pandemics ; SARS-CoV-2

The aim of this study was to estimate the seroprevalence of immunoglobulin M (IgM) and G (IgG) antibodies against SARS-CoV-2 in asymptomatic people in Wuhan. This was a cross-sectional study, which enrolled 18,712 asymptomatic participants from 154 work units in Wuhan. Pearson Chi-square test,
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antibodies, Viral/blood* ; COVID-19/immunology* ; Carrier State/immunology* ; Child ; Child, Preschool ; China/epidemiology* ; Coronavirus Nucleocapsid Proteins/immunology* ; Cross-Sectional Studies ; Female ; Humans ; Immunoglobulin G/blood* ; Immunoglobulin M/blood* ; Male ; Middle Aged ; Occupations/classification* ; Phosphoproteins/immunology* ; SARS-CoV-2/immunology* ; Seroepidemiologic Studies ; Spike Glycoprotein, Coronavirus/immunology* ; Young Adult

Hepatitis B virus core protein can self-assemble into icosahedral symmetrical viral-like particles (VLPs) in vitro, and display exogenous sequences repeatedly and densely on the surface. VLPs also have strong immunogenicity and biological activity. When the nanoparticles enter the body, they quickly induce specific humoral and cellular immune responses to exogenous antigens. In this study, we designed an HBc-VLPs that can be coupled with antigens at specific sites, and developed a set of efficient methods to prepare HBc-VLPs. Through site-specific mutation technology, the 80th amino acid of peptide was changed from Ala to Cys, a specific cross-linking site was inserted into the main immunodominant region of HBc-VLPs, and the prokaryotic expression vector pET28a(+)-hbc was constructed. After expression and purification, high purity HBc(A80C) monomer protein was assembled into HBc-VLPs nanoparticles in Phosphate Buffer. The results of particle size analysis show that the average particle size of nanoparticles was 29.8 nm. Transmission electron microscopy (TEM) showed that HBc-VLPs formed spherical particles with a particle size of about 30 nm, and its morphology was similar to that of natural HBV particles. The influenza virus antigen M2e peptide as model antigen was connected to Cys residue of HBc-VLPs by Sulfo-SMCC, an amino sulfhydryl bifunctional cross-linking agent, and M2e-HBc-VLPs model vaccine was prepared. The integrity of HBc-VLPs structure and the correct cross-linking of M2e were verified by cell fluorescence tracing. Animal immune experiments showed that the vaccine can effectively stimulate the production of antigen-specific IgG antibody in mice, which verified the effectiveness of the vaccine carrier HBc-VLPs. This study lays a foundation for the research of HBc-VLPs as vaccine vector, and help to promote the development of HBc-VLPs vaccine and the application of HBc-VLPs in other fields.
Animals ; Hepatitis B Core Antigens ; genetics ; immunology ; Immunity, Cellular ; immunology ; Immunoglobulin G ; blood ; Mice ; Mice, Inbred BALB C ; Vaccines, Virus-Like Particle ; genetics ; immunology

Antibodies, Viral ; blood ; Betacoronavirus ; Coronavirus ; immunology ; Coronavirus Infections ; immunology ; Humans ; Immunoglobulin G ; blood ; Pandemics ; Pneumonia, Viral ; immunology

Antibodies, Viral ; blood ; Betacoronavirus ; immunology ; Coronavirus Infections ; diagnosis ; Gold Colloid ; chemistry ; Humans ; Immunoassay ; methods ; Immunoglobulin G ; blood ; Immunoglobulin M ; blood ; Pandemics ; Pneumonia, Viral ; diagnosis ; Reagent Kits, Diagnostic

The ongoing pandemic of Coronavirus disease 19 (COVID-19) is caused by a newly discovered β Coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). How long the adaptive immunity triggered by SARS-CoV-2 can last is of critical clinical relevance in assessing the probability of second infection and efficacy of vaccination. Here we examined, using ELISA, the IgG antibodies in serum specimens collected from 17 COVID-19 patients at 6-7 months after diagnosis and the results were compared to those from cases investigated 2 weeks to 2 months post-infection. All samples were positive for IgGs against the S- and N-proteins of SARS-CoV-2. Notably, 14 samples available at 6-7 months post-infection all showed significant neutralizing activities in a pseudovirus assay, with no difference in blocking the cell-entry of the 614D and 614G variants of SARS-CoV-2. Furthermore, in 10 blood samples from cases at 6-7 months post-infection used for memory T-cell tests, we found that interferon γ-producing CD4
Adaptive Immunity/physiology* ; Adult ; Aged ; Antibodies, Neutralizing/blood* ; COVID-19/immunology* ; Cohort Studies ; Female ; Humans ; Immunoglobulin G/blood* ; Male ; Middle Aged ; SARS-CoV-2/immunology* ; T-Lymphocytes/physiology* ; Time Factors ; Viral Proteins/immunology*

Major depressive disorder (MDD) is the most common nonfatal disease burden worldwide. Systemic chronic low-grade inflammation has been reported to be associated with MDD progression by affecting monoaminergic and glutamatergic neurotransmission. However, whether various proinflammatory cytokines are abnormally elevated before the first episode of depression is still largely unclear. Here, we evaluated 184 adolescent patients who were experiencing their first episode of depressive disorder, and the same number of healthy individuals was included as controls. We tested the serum levels of high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), IgE, 14 different types of food antigen-specific IgG, histamine, homocysteine, S100 calcium-binding protein B, and diamine oxidase. We were not able to find any significant differences in the serum levels of hs-CRP or TNF-α between the two groups. However, the histamine level of the patients (12.35 μM) was significantly higher than that of the controls (9.73 μM, P < 0.001, Mann-Whitney U test). Moreover, significantly higher serum food antigen-specific IgG positive rates were also found in the patient group. Furthermore, over 80% of patients exhibited prolonged food intolerance with elevated levels of serum histamine, leading to hyperpermeability of the blood-brain barrier, which has previously been implicated in the pathogenesis of MDD. Hence, prolonged high levels of serum histamine could be a risk factor for depressive disorders, and antihistamine release might represent a novel therapeutic strategy for depression treatment.
Adolescent ; Biomarkers ; blood ; C-Reactive Protein ; Chronic Disease ; Cytokines ; Depressive Disorder, Major ; blood ; epidemiology ; etiology ; Female ; Food Hypersensitivity ; blood ; complications ; Histamine ; blood ; Homocysteine ; blood ; Humans ; Immunoglobulin E ; blood ; Immunoglobulin G ; blood ; immunology ; Inflammation Mediators ; blood ; Male ; Risk Factors ; S100 Calcium Binding Protein beta Subunit ; blood ; Young Adult

BACKGROUND: Plastic resins are complex chemicals that contain toluene diisocyanate (TDI) and/or trimellitic anhydride (TMA), which cause occupational allergies (OA), including respiratory allergies. Serum IgGs against TDI and TMA have been suggested as potential markers of the exposure status and as exploring cause of OA. Although TDI-specific IgG has been examined for suspected OA, TMA-specific IgG is not commonly evaluated in a urethane foam factory. This study therefore investigated both TDI- and TMA-specific IgGs in suspected OA patients and to evaluate the usefulness of the measurement of multiple chemical-specific IgG measurement for practical monitoring. METHODS: Blood samples were collected from two male workers who developed respiratory allergies supposedly caused by occupational exposure to TDI and/or TMA for the presence of TDI- and TMA-specific IgGs. In addition, blood samples from 75 male workers from a urethane foam factory, along with 87 male control subjects, were collected in 2014 and tested for the same IgGs in 2014. The presence and levels of TDI- and TMA-specific serum IgGs were measured using dot blot assays. RESULTS: We found that controls had mean concentrations of TDI- and TMA-specific IgGs of 0.98 and 2.10 μg/mL, respectively. In the two workers with respiratory allergies, the TDI-specific IgG concentrations were 15.6 and 9.51 μg/mL, and TMA-specific IgG concentrations were 4.56 and 14.4 μg/mL, which are clearly higher than those in controls. Mean concentrations of TDI- and TMA-specific IgGs in the factory workers were 1.89 and 2.41 μg/mL, respectively, and are significantly higher than those of the controls (P < 0.001 and P < 0.026 for TDI- and TMA-specific IgGs, respectively). CONCLUSION The workers suspected of OA showed an evidently high level of TDI- and TMA-specific IgG, and these levels in workers at the urethane foam factory were also significantly higher than those in controls. In conclusion, the measurement of TDI- and TMA-specific IgG among workers using plastic resins is helpful to monitor their exposure status.
Adult ; Air Pollutants, Occupational ; adverse effects ; immunology ; Environmental Monitoring ; Humans ; Immunoglobulin G ; blood ; immunology ; Japan ; Male ; Manufacturing and Industrial Facilities ; statistics & numerical data ; Middle Aged ; Occupational Diseases ; blood ; chemically induced ; Occupational Exposure ; adverse effects ; statistics & numerical data ; Phthalic Anhydrides ; immunology ; toxicity ; Respiratory Hypersensitivity ; blood ; chemically induced ; Toluene 2,4-Diisocyanate ; immunology ; toxicity ; Workforce

OBJECTIVETo investigate the changes in serum YKL-40 level and humoral immune function and their significance in children with recurrent pneumonia.

METHODSBlood samples were collected from 30 children with recurrent pneumonia (recurrent pneumonia group), 30 children with acute pneumonia (acute pneumonia group), and 30 healthy children (control group). Serum YKL-40 levels were measured by enzyme-linked immunosorbent assay. The correlation between serum YKL-40 level and laboratory indices related to humoral immune function was analyzed. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of serum YKL-40 level for recurrent pneumonia.

RESULTSThe recurrent pneumonia group had a significantly higher serum YKL-40 level than the acute pneumonia and control groups (P<0.05). The acute pneumonia group had a significantly higher serum YKL-40 level than the control group (P<0.05). Serum levels of IgG and complement 4 in the recurrent pneumonia group were significantly lower than in the acute pneumonia group (P<0.05). Serum YKL-40 level was negatively correlated with serum IgG level (r=-0.309, P=0.047) and serum complement 4 level (r=-0.324, P=0.039). The area under the ROC curve of serum YKL-40 level for diagnosing recurrent pneumonia was 0.958 (95%CI: 0.921-0.994).

CONCLUSIONSHumoral immune function is low in children with recurrent pneumonia. Serum YKL-40 may be involved in the occurrence of recurrent pneumonia and can be used as a reference index for diagnosing recurrent pneumonia.

Child, Preschool ; Chitinase-3-Like Protein 1 ; blood ; Complement C4 ; analysis ; Female ; Humans ; Immunity, Humoral ; Immunoglobulin G ; blood ; Male ; Pneumonia ; immunology ; Recurrence

Diagnosis of scrub typhus is challenging due to its more than twenty serotypes and the similar clinical symptoms with other acute febrile illnesses including leptospirosis, murine typhus and hemorrhagic fever with renal syndrome. Accuracy and rapidity of a diagnostic test to Orientia tsutsugamushi is an important step to diagnose this disease. To discriminate scrub typhus from other diseases, the improved ImmuneMed Scrub Typhus Rapid Diagnostic Test (RDT) was evaluated in Korea and Sri Lanka. The sensitivity at the base of each IgM and IgG indirect immunofluorescent assay (IFA) in Korean patients was 98.6% and 97.1%, and the specificity was 98.2% and 97.7% respectively. The sensitivity and specificity for retrospective diagnosis at the base of IFA in Sri Lanka was 92.1% and 96.1%. ImmuneMed RDT was not reactive to any serum from seventeen diseases including hemorrhagic fever with renal syndrome (n = 48), leptospirosis (n = 23), and murine typhus (n = 48). ImmuneMed RDT shows superior sensitivity (98.6% and 97.1%) compared with SD Bioline RDT (84.4% at IgM and 83.3% at IgG) in Korea. The retrospective diagnosis of ImmuneMed RDT exhibits 94.0% identity with enzyme-linked Immunosorbent assay (ELISA) using South India patient serum samples. These results suggest that this RDT can replace other diagnostic tests and is applicable for global diagnosis of scrub typhus. This rapid and accurate diagnosis will be beneficial for diagnosing and managing scrub typhus.
Antibodies, Bacterial/blood ; Enzyme-Linked Immunosorbent Assay ; Fluorescent Antibody Technique, Indirect ; Humans ; Immunoglobulin G/blood ; Immunoglobulin M/blood ; Orientia tsutsugamushi/immunology ; Reagent Kits, Diagnostic ; Retrospective Studies ; Scrub Typhus/*diagnosis/microbiology ; Sensitivity and Specificity