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

To screen the best genotypeⅠJapanese encephalitis virus subunit vaccine candidate antigens, the prMEIII gene, the polytope gene and the prMEIII-polytope fusion gene of the GenotypeⅠJapanese encephalitis virus GS strain were cloned into prokaryotic expression vector pET-30a. The recombinant proteins were obtained after the induction and purification. The prepared recombinant proteins were immunized to mice, and the immunogenicity of the subunit vaccine candidate antigens was evaluated through monitoring the humoral immune response by ELISA, detecting the neutralizing antibody titer by plaque reduction neutralization test, and testing the cell-mediated immune response by lymphocyte proliferation assay and cytokine profiling. The recombinant proteins with the molecular weights of 35 (prMEIII), 28 (polytope antigen) and 57 kDa (prMEIII-polytope) induced strong humoral and cellular immune responses in mice. Compared with prMEIII-polytope and polytope proteins, the prMEIII protein induced a significant expression of IL-2 and IFN-γ (P<0.05) and the significant lymphoproliferation of splenocytes (P<0.05). The neutralizing antibody titer induced by the prMEIII protein was close to that induced by the commercial attenuated vaccine SA14-14-2 (P>0.05). The study suggests that the prMEIII protein can be used for the development of the Japanese encephalitis virus subunit vaccine.
Animals ; Antibodies, Viral ; blood ; Antigens, Viral ; immunology ; Encephalitis Virus, Japanese ; immunology ; Encephalitis, Japanese ; immunology ; prevention & control ; Immunogenicity, Vaccine ; Mice ; Mice, Inbred BALB C ; Vaccines, Subunit ; immunology ; Viral Vaccines ; immunology

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*

OBJECTIVE: To retrospectively analyze the identification results of irregular antibodies, to clarify the distribution features and to explore the relation of alloantibodies and autoantibodies with the immunized history of patients and disease kinds. METHODS: 49 820 patients who applied for red blood transfusion during Sep 1st 2017 to Sep 1st 2018 were selected. All the specimens were screened for the antibody by microcolumn gel antiglobulin technique, which then were identified for irregular antibody. RESULTS: Antibodies were found in 861 (1.73%) of all 49 820 transfused samples. The alloimmunization history of the patients with antibodies was significantly different between male and female (χ=18.54，P＜0.01). The alloantibody was the most common, accounting for 59.50% in all of the antibodies. Warm autoantibody, anti-E, anti-M, anti-cE and anti-Ce accounted for 68.5% of the antibodies. The blood group of Rh, MNS and Lewis were responsible for 92.40% of alloantibody, especially anti-E accounted for the largest percentage(38.60%) of alloantibody. Patients with alloantiboies experienced much more the alloimmunization and transfusion history (χ=20.13，P＜0.01；χ=5.40，P＜0.05) . The distribution of auto and alloantibody was very significantly different among the ddifferent isease (χ=51.8，P＜0.01), Hematopathy, solid tumor and osteoarthropathy were often associated with alloantibody, otherwise, autoantibodies often occurred in hematopathy and autoimmune disease. CONCLUSION The most important factor that results in antibody-screening positive is alloantibody, in which anti-E antibody from Rh blood group system in most common.
Antibodies ; immunology ; Blood Group Antigens ; Blood Transfusion ; Erythrocytes ; Female ; Humans ; Isoantibodies ; Male ; Retrospective Studies

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

BACKGROUND: The coronavirus disease 2019 (COVID-19) outbreak occurred during the flu season around the world. This study aimed to analyze the impact of influenza A virus (IAV) exposure on COVID-19. METHODS: Seventy COVID-19 patients admitted to the hospital during January and February 2020 in Wuhan, China were included in this retrospective study. Serum tests including respiratory pathogen immunoglobulin M (IgM) and inflammation biomarkers were performed upon admission. Patients were divided into common, severe, and critical types according to disease severity. Symptoms, inflammation indices, disease severity, and fatality rate were compared between anti-IAV IgM-positive and anti-IAV IgM-negative groups. The effects of the empirical use of oseltamivir were also analyzed in both groups. For comparison between groups, t tests and the Mann-Whitney U test were used according to data distribution. The Chi-squared test was used to compare disease severity and fatality between groups. RESULTS: Thirty-two (45.71%) of the 70 patients had positive anti-IAV IgM. Compared with the IAV-negative group, the positive group showed significantly higher proportions of female patients (59.38% vs. 34.21%, χ = 4.43, P = 0.035) and patients with fatigue (59.38% vs. 34.21%, χ = 4.43, P = 0.035). The levels of soluble interleukin 2 receptor (median 791.00 vs. 1075.50 IU/mL, Z = -2.70, P = 0.007) and tumor necrosis factor α (median 10.75 vs. 11.50 pg/mL, Z = -2.18, P = 0.029) were significantly lower in the IAV-positive group. Furthermore, this group tended to have a higher proportion of critical patients (31.25% vs. 15.79%, P = 0.066) and a higher fatality rate (21.88% vs. 7.89%, P = 0.169). Notably, in the IAV-positive group, patients who received oseltamivir had a significantly lower fatality rate (0 vs. 36.84%, P = 0.025) compared with those not receiving oseltamivir. CONCLUSIONS The study suggests that during the flu season, close attention should be paid to the probability of IAV exposure in COVID-19 patients. Prospective studies with larger sample sizes are needed to clarify whether IAV increases the fatality rate of COVID-19 and to elucidate any benefits of empirical usage of oseltamivir.
Adult ; Aged ; Antibodies, Viral/blood* ; Betacoronavirus ; COVID-19 ; Coronavirus Infections/mortality* ; Female ; Humans ; Immunoglobulin M/blood* ; Influenza A virus/immunology* ; Influenza, Human/complications* ; Male ; Middle Aged ; Pandemics ; Pneumonia, Viral/mortality* ; Retrospective Studies ; SARS-CoV-2 ; Severity of Illness Index

OBJECTIVE: To observe the clinical effect of plasma exchange and tocilizumab in treatment of patients with severe coronavirus disease 2019 (COVID-19). METHODS: Six patients with severe COVID-19 admitted in First Affiliated Hospital of Bengbu Medical College from January 25 to February 25, 2020. Three patients were treated with plasma exchange and three patients were treated with tocilizumab. The effect on excessive inflammatory reaction of plasma exchange and tocilizumab was observed. RESULTS: The C-reactive protein (CRP) and IL-6 levels were significantly decreased and the lymphocyte and prothrombin time were improved in 3 patients after treatment with plasma exchange; while inflammation level was not significantly decreased, and lymphocyte and prothrombin time did not improve in 3 patients treated with tocilizumab. CONCLUSIONS For severe COVID-19 patients with strong inflammatory reaction, plasma exchange may be preferred.
Antibodies, Monoclonal, Humanized ; administration & dosage ; Betacoronavirus ; isolation & purification ; Coronavirus Infections ; blood ; immunology ; therapy ; Cytokine Release Syndrome ; therapy ; Humans ; Pandemics ; Plasma Exchange ; standards ; Pneumonia, Viral ; blood ; immunology ; therapy ; Prothrombin Time ; Treatment Outcome

Objective: Long-term seroprotection the hepatitis A vaccine is essential for the prevention of disease from the hepatitis A virus (HAV). Due to documented difficulties during decade-long follow-ups after receiving vaccines, statistical-modeling approaches have been applied to predict the duration of immune protection. Methods: Based on five-year follow-up data from a randomized positive-controlled trial among Chinese children (1-8 years old) following a 0, 6 months vaccination schedule, a power-law model accounting for the kinetics of B-cell turnover, as well as a modified power-law model considering a memory-B-cell subpopulation, were fitted to predict the long-term immune responses induced by HAV vaccination (Healive or Havrix). Anti-HAV levels of each individual and seroconversion rates up to 30 years after vaccination were predicted. Results: A total of 375 participants who completed the two-dose vaccination were included in the analysis. Both models predicted that, over a life-long period, participants vaccinated with Healive would have close but slightly higher antibody titers than those of participants vaccinated with Havrix. Additionally, consistent with previous studies, more than 90% of participants were predicted to maintain seroconversion for at least 30 years. Moreover, the modified power-law model predicted that the antibody titers would reach a plateau level after nearly 15 years post-vaccination. Conclusions Based on the results of our modeling, Healive may adequately induce long-term immune responses following a 0, 6 months vaccination schedule in children induction of memory B cells to provide stable and durable immune protection.
Adolescent ; Child ; Child, Preschool ; China ; Female ; Hepatitis A ; immunology ; Hepatitis A Antibodies ; blood ; Hepatitis A Vaccines ; administration & dosage ; Humans ; Immunity, Active ; Infant ; Male ; Models, Statistical ; Vaccination ; statistics & numerical data