IgG3 and IgM Identified as Key to SARS-CoV-2 Neutralization in Convalescent Plasma Pools

Analysis of convalescent plasma derived from individuals has shown that IgG3 has the most important role in binding to SARS-CoV-2 antigens; however, this has not yet been confirmed in large studies, and the link between binding and neutralization has not been confirmed. By analyzing plasma pools consisting of 247–567 individual convalescent donors, we demonstrated the binding of IgG3 and IgM to Spike-1 protein and the receptor-binding domain correlates strongly with viral neutralization in vitro. Furthermore, despite accounting for only approximately 12% of total immunoglobulin mass, collectively IgG3 and IgM account for approximately 80% of the total neutralization. This may have important implications for the development of potent therapies for COVID-19, as it indicates that hyperimmune globulins or convalescent plasma donations with high IgG3 concentrations may be a highly efficacious therapy.

PSXIV-22 Selection for low fecal egg count estimated breeding value correlates with greater circulating antibody in sheep

Sheep selected for resistance to gastro-intestinal parasites have been shown to have greater survivability to weaning. Data from Katahdin sheep indicates that selection based on post-weaning fecal egg count estimated breeding values (PWFEC EBV) may further improve generalized immunity. However, no data exists to confirm this increased circulating antibody occurs in breeds genetically unrelated to Katahdins. In the fall of 2020 post-weaning blood and fecal samples were collected from Shropshire sheep (n = 42) and Polypay sheep (n = 91). The blood samples were analyzed for total immunoglobulin-G (IgG) using ELISA. Shropshire sheep were sorted into low (PWFEC EBV < 0) and high (PWFEC EBV > 0) groups based on fecal egg count (FEC), which were analyzed via a modified McMaster’s method. Polypay sheep were sorted into three groups by PWEC EBV; A (< -50) B (>-50 < +50) and C (>+50). In Shropshire group, individuals with low FEC had greater average IgG concentration (87.9 µg/mL) than those with high FEC (62.4 µg/mL) (P > 0.05). In the Polypay group, sheep in PWFEC EBV group A had numerically higher IgG concentration (86.2 µg/mL) than sheep in group B (71.2 µg/mL) and group C (53.1 µg/mL) (P > 0.05). While data in either breed were not significant, the trend observed across breeds indicate that sheep with a lower PWFEC EBV have numerically greater circulating antibody.

Comparison of biochemical and immunological biomarker levels of patients with COVID-19 with healthy individuals

Objectives It was aimed to compare Alpha-1 antitrypsin (AAT), Alpha-1 acid glycoprotein (AGP), Total Immunoglobulin M (Total IgM), Total Immunoglobulin G (Total IgG), Galectin-3 (Gal3), and severe acute respiratory syndrome coronavirus 2 IgG (SARS-CoV-2 IgG) levels in patients with COVID-19 and healthy individuals. Methods The study included a total of 86 participants, 44 patients diagnosed with COVID-19 by real-time reverse transcription-polymerase chain reaction (rRT-PCR) test and 42 as the control group. AAT, AGP, Total IgM, and Total IgG levels were measured using the immunoturbidimetric method. Gal3 and SARS-CoV-2 IgG levels were measured using the chemiluminescent microparticle immunoassay method. Results AAT, AGP, Total IgG, Gal3, and SARS-CoV-2 IgG levels were found to be significantly higher in the patient group compared to the control group (p<0.001 for all tests). In the patient group, there was a moderate correlation between AAT-AGP and SARS-CoV-2 IgG-AAT (r=0.692; r=0.561, respectively). Conclusions High levels of AAT, AGP, Total IgG, Gal3, and SARS-CoV-2 IgG in the patient group and correlations between variables suggest that these parameters may be involved in the pathogenesis of the disease and provide an idea about the prognosis of the disease. However, new studies on this subject are needed in order to clearly reveal the laboratory tests related to the clinical course of the disease.

Evaluation of the effect of lidocaine epidural injection on immunological indices in dogs under total intravenous anesthesia submitted to ovariohysterectomy

This study aimed to evaluate the effects of epidural anaesthesia with lidocaine in combination with general anaesthesia with propofol on some immunologic indices in dogs undergoing ovariohysterectomy. Twelve adult dogs were anesthetized with propofol (induction: 7 mg/kg; maintenance: 0.4 mg/kg/min) and were then allocated into either groups of epidural saline (control) or epidural lidocaine (4 mg/kg; treatment). All the included animals underwent ovariohysterectomy operation. The immune responses, hematologic parameters and cortisol levels were assessed in the predetermined intervals. Evaluation of the innate immunity revealed higher significant levels in the bactericidal, lysozyme and myeloperoxidase activities at 4 hours after surgery in the treatment. In the humoral immunity, the total immunoglobulin level was significantly higher in the treatment. In the assessment of cellular immunity, higher significant values were detected in the delayed skin sensitivity to phytohemagglutinine injection after 48 and 72 hours in the treatment. Moreover, higher significant levels were observed in the number and percentage of lymphocytes as well as an increase in the percentage of monocytes in the treatment at 4 hours after the operation. Notably, the cortisol hormone in the treatment was lower than control at 4 hours of the surgery. In conclusion, epidural anaesthesia with lidocaine when added to general anaesthesia with propofol attenuated the suppression of the innate and cellular immune responses produced by anaesthesia and surgery in the dogs.

Seroprevalence of SARS-CoV-2, Symptom Profiles and Sero-Neutralization in a Suburban Area, France

The World Health Organisation recommends monitoring the circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We investigated anti–SARS-CoV-2 total immunoglobulin (IgT) antibody seroprevalence and in vitro sero-neutralization in Nancy, France, in spring 2020. Individuals were randomly sampled from electoral lists and invited with household members over 5 years old to be tested for anti–SARS-CoV-2 (IgT, i.e., IgA/IgG/IgM) antibodies by ELISA (Bio-rad); the sero-neutralization activity was evaluated on Vero CCL-81 cells. Among 2006 individuals, the raw seroprevalence was 2.1% (95% confidence interval 1.5 to 2.9), was highest for 20- to 34-year-old participants (4.7% (2.3 to 8.4)), within than out of socially deprived area (2.5% vs. 1%, p = 0.02) and with than without intra-family infection (p < 10−6). Moreover, 25% of participants presented at least one COVID-19 symptom associated with SARS-CoV-2 positivity (p < 10−13), with highly discriminant anosmia or ageusia (odds ratio 27.8 [13.9 to 54.5]); 16.3% (6.8 to 30.7) of seropositive individuals were asymptomatic. Positive sero-neutralization was demonstrated in vitro for 31/43 seropositive subjects. Regarding the very low seroprevalence, a preventive effect of the lockdown in March 2020 can be assumed for the summer, but a second COVID-19 wave, as expected, could be subsequently observed in this poorly immunized population.

Impact of Nematode Infections on Non-specific and Vaccine-Induced Humoral Immunity in Dual-Purpose or Layer-Type Chicken Genotypes

Nematode infections may induce immune-modulatory effects and influence host-immune responses to other pathogens. The aim of the study was to investigate whether a mixed nematode-infection influences non-specific and vaccine-induced humoral immunity against Newcastle Disease Virus (NDV), Infectious Bronchitis Virus (IBV), and Avian Metapneumovirus (AMPV) in already vaccinated hens of a dual-purpose (Lohmann Dual, LD) or a layer genotype (Lohmann Brown Plus; LB). Until 17 weeks-of-age, LD (n = 70) and LB (n = 109) hens were vaccinated against major bacterial and viral diseases and coccidiosis. At 24 weeks-of-age, the hens received either a placebo or an oral inoculation of 1,000 infectious eggs of A. galli and H. gallinarum. Plasma total immunoglobulin (Ig) isotypes (IgY, IgM, IgA) levels and vaccine-induced antibody titers against NDV, IBV, and AMPV were determined from 2 to 18 weeks post-infection (wpi). Infections had no suppressing effect on total Ig isotypes IgY, IgM, and IgA as well as on vaccine-induced antibody titers against NDV, IBV, and AMPV (P &gt; 0.05). Overall, LB hens had higher levels of IgY, IgM, and IgA than those of LD hens (P &lt; 0.05). There were no differences between IBV titers of the two genotypes (P &gt; 0.05). Independent of infection status of the hens, NDV titers were higher in LB hens than in LD hens at wpi 2 (P &lt; 0.05), but not in following weeks (P &gt; 0.05). Uninfected LD hens had lower AMPV titers than their infected counterparts at 6 and 14 wpi (P &lt; 0.05). Regardless of nematode infection, LD hens revealed a higher risk of responding weak to vaccination against NDV (odds ratio = 5.45; P = 0.021) and AMPV (odds ratio = 13.99, P &lt; 0.001) than did LB hens (P &gt; 0.05). We conclude that nematode infections have no adverse effects on non-specific and vaccine-induced humoral immunity in either genotype. LB hens have higher levels of total immunoglobulin isotypes than LD hens. Except for IBV, vaccine-induced humoral immune responses show a dependency on genotype. Dual-purpose hens show lower responsiveness to vaccinations against NDV and AMPV, possibly due to factors associated with increased body fat reserves in this genotype.

Seroprevalence of SARS-CoV-2, symptom profiles and seroneutralization during the first COVID-19 wave in a suburban area, France

BackgroundThe World Health Organisation recommends monitoring the circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We aimed to estimate anti–SARS-CoV-2 total immunoglobulin (IgT) antibody seroprevalence and describe symptom profiles and in vitro seroneutralization in Nancy, France, in spring 2020.MethodsIndividuals were randomly sampled from electoral lists and invited with household members over 5 years old to be tested for anti–SARS-CoV-2 (IgT, i.e. IgA/IgG/IgM) antibodies by ELISA (Bio-rad). Serum samples were classified according to seroneutralization activity >50% (NT50) on Vero CCL-81 cells. Age- and sex-adjusted seroprevalence was estimated. Subgroups were compared by chi-square or Fisher exact test and logistic regression.ResultsAmong 2006 individuals, 43 were SARS-CoV-2–positive; the raw seroprevalence was 2.1% (95% confidence interval 1.5 to 2.9), with adjusted metropolitan and national standardized seroprevalence 2.5% (1.8 to 3.3) and 2.3% (1.7 to 3.1). Seroprevalence was highest for 20-to 34-year-old participants (4.7% [2.3 to 8.4]), within than out of socially deprived area (2.5% vs 1%, P=0.02) and with than without intra-family infection (p<10−6). Moreover, 25% (23 to 27) of participants presented at least one COVID-19 symptom associated with SARS-CoV-2 positivity (p<10−13), with anosmia or ageusia highly discriminant (odds ratio 27.8 [13.9 to 54.5]), associated with dyspnea and fever. Among the SARS-CoV-2-positives, 16.3% (6.8 to 30.7) were asymptomatic. For 31 of these individuals, positive seroneutralization was demonstrated in vitro.ConclusionsIn this population of very low anti-SARS-CoV-2 antibody seroprevalence, a beneficial effect of the lockdown can be assumed, with frequent SARS-CoV-2 seroneutralization among IgT-positive patients.Key MessagesTotal immunoglobulin antibody (IgT) measurement is an accurate tool to monitor the circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and a key biological feature to assume the spread of COVID-19 later after the appearance of symptoms.IgT seroprevalence was 2.1% in the Grand Nancy Metropolitan area, France; was highest for young adults; in socially deprived area, but this was not confirmed at the individual level; and was associated with high intra-family viral transmission.About two thirds of IgT-positive individuals exhibited SARS-CoV-2–positive seroneutralization.Trial registrationNCT04448769