anti-S1 IgG Research Articles

Serological and viral genetic features of patients with COVID-19 in a selected German patient cohort\u2014correlation with disease characteristics

To study host-virus interactions after SARS coronavirus-2 (SARS-CoV-2) infection, genetic virus characteristics and the ensued humoral immune response were investigated for the first time. Fifty-five SARS-CoV-2-infected patients from the early pandemic phase were followed up including serological testing and whole genome sequencing. Anti-spike and nucleocapsid protein (S/N) IgG and IgM levels were determined by screening ELISA and IgG was further characterized by reactivity to S-subunit 1 (anti-S1), S-subunit 2 (anti-S2) and anti-N. In 55 patients, 90 genetic SARS-CoV-2 changes including 48 non-synonymous single nucleotide variants were identified. Phylogenetic analysis of the sequencing data showed a cluster representing a local outbreak and various family clusters. Anti-S/N and anti-N IgG were detected in 49 patients at an average of 83 days after blood collection. Anti-S/N IgM occurred significantly less frequently than IgG whereas anti-S2 was the least prevalent IgG reactivity (P < 0.05, respectively). Age and overweight were significantly associated with higher anti-S/N and anti-S1 IgG levels while age only with anti-N IgG (multiple regression, P < 0.05, respectively). Anti-S/N IgG/IgM levels, blood group A + , cardiovascular and tumour disease, NSP12 Q444H and ORF3a S177I were independent predictors of clinical characteristics with anti-S/N IgM being associated with the need for hospitalization (multivariate regression, P < 0.05, respectively). Anti-SARS-CoV-2 antibody generation was mainly affected by higher age and overweight in the present cohort. COVID-19 traits were associated with genetic SARS-CoV-2 variants, anti-S/N IgG/IgM levels, blood group A + and concomitant disease. Anti-S/N IgM was the only antibody associated with the need for hospitalization.

Correlation between a quantitative anti-SARS-CoV-2 IgG ELISA and neutralization activity.

In the current COVID‐19 pandemic, a better understanding of the relationship between merely binding and functionally neutralizing antibodies is necessary to characterize protective antiviral immunity following infection or vaccination. This study analyzes the level of correlation between the novel quantitative EUROIMMUN Anti‐SARS‐CoV‐2 QuantiVac ELISA (IgG) and a microneutralization assay. A panel of 123 plasma samples from a COVID‐19 outbreak study population, preselected by semiquantitative anti‐SARS‐CoV‐2 IgG testing, was used to assess the relationship between the novel quantitative ELISA (IgG) and a microneutralization assay. Binding IgG targeting the S1 antigen was detected in 106 (86.2%) samples using the QuantiVac ELISA, while 89 (72.4%) samples showed neutralizing antibody activity. Spearman's correlation analysis demonstrated a strong positive relationship between anti‐S1 IgG levels and neutralizing antibody titers (r s = 0.819, p < 0.0001). High and low anti‐S1 IgG levels were associated with a positive predictive value of 72.0% for high‐titer neutralizing antibodies and a negative predictive value of 90.8% for low‐titer neutralizing antibodies, respectively. These results substantiate the implementation of the QuantiVac ELISA to assess protective immunity following infection or vaccination.

Induction of SARS-CoV-2-Specific IgG and IgA in Serum and Milk with Different SARS-CoV-2 Vaccines in Breastfeeding Women: A Cross-Sectional Study in Northern Spain.

Breastfeeding mothers were excluded from the clinical trials conducted for vaccines against SARS-CoV-2. Since the start of the vaccination, some doubts have arisen regarding its compatibility with breastfeeding. The aim of this study was to analyse the presence of anti-SARS-CoV-2 antibodies in breast milk and serum (IgG and IgA) of vaccinated breastfeeding women. The main variables of the observational study were: adverse related events after vaccination and determination of the presence of IgG and IgA isotypes antibodies in serum and in breast milk of vaccinated women against the SARS-CoV-2 antigens. Results: 110 breastfeeding mothers were included; 70 women (63.6%) were vaccinated with two doses of BNT162b2, 20 women (18.2%) with two doses of mRNA-1273, and 20 women (18.2%) with a single dose of ChAdOx1-S. Regarding adverse reactions and vaccine safety, 38 women had no adverse reactions; 20 (18.2%) had general malaise or adenopathies; 10 (9.1%) had a headache; and 7 (6.4%) had fever. When analysing IgG antibodies, significantly higher levels of antibodies were found in serum and breast milk from mothers vaccinated with BNT162b2 or mRNA-1273 vs. ChAdOx1-S (p < 0.001 and p = 0.001, respectively). Analysing IgA antibodies, significant differences were found when comparing mean values in serum from mothers vaccinated with BNT162b2 or mRNA-1273 vs. ChAdOx1-S (0.12, 0.16, and 0.02, respectively; p < 0.001) and breast milk of mothers vaccinated when comparing BNT16b2 vs. ChAdOx1-S. All vaccinated breastfeeding mothers had serum anti-S1 IgG antibodies in response to vaccination against SARS-CoV-2, regardless of the commercial vaccine administered. Conclusions: the anti-SARS-CoV-2 vaccines were well tolerated by the mothers and the breastfed infant. In addition, breastfeeding mothers offer their infants IgA and IgG isotype antibodies directed against SARS-CoV-2 protein S in breast milk.

Picture of the Favourable Immune Profile Induced by Anti-SARS-CoV-2 Vaccination.

COVID-19 pandemic has hit people’s health, economy, and society worldwide. Great confidence in returning to normality has been placed in the vaccination campaign. The knowledge of individual immune profiles and the time required to achieve immunological protection is crucial to choose the best vaccination strategy. We compared anti-S1 antibody levels produced over time by BNT162b2 and AZD1222 vaccines and evaluated the induction of antigen-specific T-cells. A total of 2569 anti-SARS-CoV-2 IgG determination on dried blood spot samples were carried out, firstly in a cohort of 1181 individuals at random time-points, and subsequently, in an independent cohort of 88 vaccinated subjects, up to the seventeenth week from the first dose administration. Spike-specific T-cells were analysed in seronegative subjects between the two doses. AZD1222 induced lower anti-S1 IgG levels as compared to BNT162b2. Moreover, 40% of AZD1222 vaccinated subjects and 3% of BNT162b2 individuals resulted in seronegative during all the time-points, between the two doses. All these subjects developed antigen-specific T cells, already after the first dose. These results suggest that this test represents an excellent tool for a wide sero-surveillance. Both vaccines induce a favourable immune profile guaranteeing efficacy against severe adverse effects of SARS-CoV-2 infection, already after the first dose administration.

Humoral Responses to Single-Dose BNT162b2 mRNA Vaccination in Dialysis Patients Previously Infected With SARS-CoV-2.

Seroconversion rates following infection and vaccination are lower in dialysis patients compared to healthy controls. There is an urgent need for the characterization of humoral responses and success of a single-dose SARS-CoV-2 vaccination in previously infected dialysis patients. We performed a dual-center cohort study comparing three different groups: 25 unvaccinated hemodialysis patients after PCR-confirmed COVID-19 (Group 1), 43 hemodialysis patients after two-time BNT162b2 vaccination without prior SARS-CoV-2 infection (Group 2), and 13 single-dose vaccinated hemodialysis patients with prior SARS-CoV-2 infection (Group 3). Group 3 consists of seven patients from Group 1 and 6 additional patients with sera only available after single-dose vaccination. Anti-S1 IgG, neutralizing antibodies, and antibodies against various SARS-CoV-2 protein epitopes were measured 3 weeks after the first and 3 weeks after the second vaccination in patients without prior SARS-CoV-2 infection, 6 weeks after the onset of COVID-19 in unvaccinated patients, and 3 weeks after single-dose vaccination in patients with prior SARS-CoV-2 infection, respectively. Unvaccinated patients after COVID-19 showed a significantly higher neutralizing antibody capacity than two-time vaccinated patients without prior COVID-19 [median (IQR) percent inhibition 88.0 (71.5–95.5) vs. 50.7 (26.4–81.0); P = 0.018]. After one single vaccine dose, previously infected individuals generated 15- to 34-fold higher levels of anti-S1 IgG than age- and dialysis vintage-matched unvaccinated patients after infection or two-time vaccinated patients without prior SARS-CoV-2 infection with a median (IQR) index of 274 (151–791) compared to 18 (8–41) and 8 (1–21) (for both P < 0.001). With a median (IQR) percent inhibition of 97.6 (97.2–98.9), the neutralizing capacity of SARS-CoV-2 antibodies was significantly higher in single-dose vaccinated patients with prior SARS-CoV-2 infection compared to other groups (for both P < 0.01). Bead-based analysis showed high antibody reactivity against various SARS-CoV-2 spike protein epitopes after single-dose vaccination in previously infected patients. In conclusion, single-dose vaccination in previously infected dialysis patients induced a strong and broad antibody reactivity against various SARS-CoV-2 spike protein epitopes with high neutralizing capacity.

Heterologous ChAdOx1 nCoV-19/BNT162b2 Prime-Boost Vaccination Induces Strong Humoral Responses among Health Care Workers.

Despite limited data on safety and immunogenicity, heterologous prime-boost vaccination is currently recommended for individuals with ChAdOx1 nCoV-19 prime immunization in certain age groups. In this prospective, single-center study we included 166 health care workers from Heidelberg University Hospital who received either heterologous ChAdOx1 nCoV-19/BNT162b2, homologous BNT162b2 or homologous ChAdOx1 nCoV-19 vaccination between December 2020 and May 2021. We measured anti-S1 IgG, SARS-CoV-2 specific neutralizing antibodies, and antibodies against different SARS-CoV-2 fragments 0–3 days before and 19–21 days after boost vaccination. Before boost, 55/70 (79%) ChAdOx1 nCoV-19-primed compared with 44/45 (98%) BNT162b2-primed individuals showed positive anti-S1 IgG with a median (IQR) anti-S1 IgG index of 1.95 (1.05–2.99) compared to 9.38 (6.26–17.12). SARS-CoV-2 neutralizing antibodies exceeded the threshold in 24/70 (34%) of ChAdOx1 nCoV-19-primed and 43/45 (96%) of BNT162b2-primed individuals. After boosting dose, median (IQR) anti-S1 IgG index in heterologous ChAdOx1 nCoV-19/BNT162b2 vaccinees was 116.2 (61.84–170), compared to 13.09 (7.03–29.02) in homologous ChAdOx1 nCoV-19 and 145.5 (100–291.1) in homologous BNT162b2 vaccinees. All boosted vaccinees exceeded the threshold for neutralization, irrespective of their vaccination scheme. Vaccination was well-tolerated overall. We show that heterologous ChAdOx1 nCoV-19/BNT162b2 vaccination is safe and induces a strong and broad humoral response in healthy individuals.

Immunogenicity of the BNT162b2 COVID-19 mRNA vaccine and early clinical outcomes in patients with haematological malignancies in Lithuania: a national prospective cohort study

BackgroundHaematological malignancies and their treatments are likely to affect SARS-CoV-2 vaccine efficacy. We aimed to evaluate serological response to BNT162b2 vaccine in patients with haematological malignancies by type of treatment.MethodsOur national prospective cohort study was done in Lithuania and assessed serological response to one and two BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccine doses in healthy health-care workers and in patients with haematological malignancies. Eligible participants were aged 18 years or older, had received both vaccine doses, and had available biobanked blood samples from before vaccination and after the second dose. Biobanked samples and health data were obtained from Vilnius University Hospital Santaros Klinikos Biobank. Abbott Architect SARS-CoV-2 IgG Quant II chemiluminescent microparticle assay was used to quantify serum anti-SARS-CoV-2-S1 IgG antibody (anti-S1 IgG antibody) concentrations 0–10 days before the first BNT162b2 vaccine, on the day of second immunisation (around day 21), and 7 to 21 days after the second immunisation. Adverse events were assessed by a standardised questionnaire. Breakthrough infections were characterised clinically and by SARS-CoV-2 genotyping whenever possible. This study is registered with ClinicalTrials.gov, NCT04871165.FindingsBetween Jan 8 and April 21, 2021, 885 participants with haematological malignancies were included in the study. 857 patients were anti-S1 IgG seronegative at timepoint 0 and constituted the main analysis cohort. The age-matched comparison was made between 315 patients with haematological malignancies who were aged 18–60 years and 67 healthy health-care workers in the same age group. Patients aged 18–60 years with haematological malignancies had lower median anti-S1 IgG antibody responses after two BNT162b2 vaccine doses than did health-care workers of the same age group (median 6961 AU/mL [IQR 1292–20 672] vs 21 395 AU/mL [14 831–33 553]; p<0·0001). Compared with untreated patients with haematological malignancies (n=53; median 5761 AU/mL [629–16 141]), patients actively treated with Bruton tyrosine kinase inhibitors (BTKIs; n=44; 0 AU/mL [0–7]; p<0·0001), ruxolitinib (n=16; 10 AU/mL [0–45]; p<0·0001), venetoclax (n=10; 4 AU/mL [0–1218]; p=0·0005), or anti-CD20 antibody therapy (n=87; 17 AU/mL [1–2319]; p<0·0001) showed particularly poor anti-S1 IgG antibody responses following two BNT162b2 doses. Patients being treated with tyrosine kinase inhibitors (n=41; 10 537 AU/mL [IQR 2335–19 388]) or patients who received autologous haematopoietic stem-cell transplantation (HSCT; n=192; 6203 AU/mL [1451–16 834]) or allogeneic HSCT (n=122; 6304 AU/mL [1120–16 913]) were among the subgroups with the highest numerical responses. Nine SARS-CoV-2 infections and three COVID-19 deaths were observed among fully vaccinated patients with haematological malignancies.InterpretationPatients with haematological malignancies mount blunted and heterogeneous antibody responses to the full course of BNT162b2 mRNA vaccination. Patients who are actively treated with BTKIs, ruxolitinib, venetoclax, or anti-CD20 antibody therapies seem to be the most negatively affected and might be left unprotected from SARS-CoV-2 infection. Breakthrough severe SARS-CoV-2 infections in fully vaccinated patients with haematological malignancies emphasise the importance of ongoing strict adherence to non-pharmacological interventions and household vaccination while SARS-CoV-2 is circulating in the community.FundingVilnius University Hospital Santaros Klinikos.TranslationFor the Lithuanian translation of the abstract see Supplementary Materials section.

Blunted humoral response after mRNA vaccine in patients with haematological malignancies

Blunted humoral response after mRNA vaccine in patients with haematological malignancies

Early Humoral Responses of Hemodialysis Patients after COVID-19 Vaccination with BNT162b2.

Patients receiving hemodialysis are at high risk for both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe coronavirus disease 2019. A lifesaving vaccine is available, but sensitivity to vaccines is generally lower in patients on dialysis. Little is yet known about antibody responses after coronavirus disease 2019 (COVID-19) vaccination in this vulnerable group. In this prospective single-center study, we included 22 patients on dialysis and 46 healthy controls from Heidelberg University Hospital between December 2020 and February 2021. We measured anti-S1 IgG with a threshold index for detection greater than one, neutralizing antibodies with a threshold for viral neutralization of ≥30%, and antibodies against different SARS-CoV2 fragments 17-22 days after the first dose and 18-22 days after the second dose of the mRNA vaccine BNT162b2. After the first vaccine dose, four of 22 (18%) patients on dialysis compared with 43 of 46 (93%) healthy controls developed positive anti-S1 IgG, with a median anti-S1 IgG index of 0.2 (interquartile range, 0.1-0.7) compared with nine (interquartile range, 4-16), respectively. SARS-CoV2 neutralizing antibodies exceeded the threshold for neutralization in four of 22 (18%) patients on dialysis compared with 43 of 46 (93%) healthy controls, with a median percent inhibition of 11 (interquartile range, 3-24) compared with 65 (interquartile range, 49-75), respectively. After the second dose, 14 of 17 (82%) patients on dialysis developed neutralizing antibodies exceeding the threshold for viral neutralization and antibodies against the receptor binding S1 domain of the spike protein, compared with 46 of 46 (100%) healthy controls, respectively. The median percent inhibition was 51 (interquartile range, 32-86) compared with 98 (interquartile range, 97-98) in healthy controls. Patients receiving long-term hemodialysis show a reduced antibody response to the first and second doses of the mRNA vaccine BNT162b2. The majority (82%) develop neutralizing antibodies after the second dose but at lower levels than healthy controls.

Antibody Kinetics and Durability in SARS-CoV-2 mRNA Vaccinated Solid Organ Transplant Recipients.

Decline in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antispike antibodies over time following natural infection and vaccination have been reported,1–3 though kinetics and durability of antispike antibodies in vaccinated transplant recipients are unknown. We sought to quantify antispike antibody titers over a 3 mo period in transplant recipients who completed the mRNA vaccine series. As previously reported,4,5 serologic testing was undertaken on the Roche Elecsys anti-SARS-CoV-2 S enzyme immunoassay (range <0.4–>250 U/mL [positive ≥0.8 U/mL]) which tests for antibodies against the receptor-binding domain of the spike protein or EUROIMMUN enzyme immunoassay (positive ≥1.1 arbitrary units) which tests for IgG to the S1 domain of the spike protein at 3 time points: before dose 2, 1 mo and 3 mo after dose 2. Participants underwent vaccination between 16 December 2020 and 13 March 2021, and this study was approved by the Johns Hopkins Institutional Review Board. Overall, 40/305 (13%) had detectable antibody at median (interquartile range [IQR]) 21 (18–25) d after dose 1; 169/305 (55%) had detectable antibody at median (IQR) 29 (28–31) d after dose 2; and 203/305 (67%) had detectable antibody at median (IQR) 90 (88–92) d after dose 2. Among the participants with detectable antibody at 1 mo, 6/169 (4%) fell below the threshold of positivity at 3 mo (Table 1). Titers decreased in 59/169 (35%), increased in 74/169 (43%), and remained constant in 36/169 (21%). TABLE 1. - Antispike antibody sero-response 3 mo following SARS-CoV-2 vaccine dose 2 in transplant recipients, stratified by antibody response 1 mo after 2-dose mRNA vaccine series Sero-response after 3 mo Negative Low-positive High-positive Sero-response after 1 mo Negative 96 (70) 31 (23) 9 (7) Low-positive 5 (7) 35 (47) 35 (47) High-positive 1 (1) 18 (19) 75 (80) Negative sero-response was defined per manufacturer data as EUROIMMUN anti-S1 IgG <1.1 arbitrary units (AU) or Roche Elecsys anti-RBD pan Ig <0.8 units/mL. Low-positive sero-response was defined as anti-S1 IgG 1.1–4 AU or anti-RBD pan Ig 0.8–50 units/mL. High-positive sero-response was defined as anti-S1 IgG >4 AU or anti-RBD pan Ig >50 units/mL.IgG, immunoglobulin G; RBD, receptorbinding domain; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2. Among those with any positive titer after dose 2, median (IQR [range]) change between 1 mo and 3 mo antibody levels was 0 (0–75 [−166.8.1 to 247.12]; Roche) and −1.19 (−2.04 to 0.55, [−4.2 to 3.02]; EUROIMMUN). Among those with low-positive titers at 1 mo, 35/75 (47%) remained in the low-positive range and 35/75 (47%) became high-positive. Among those with high-positive titers at 1 mo, 18/94 (19%) dropped to the low-positive range and 75/94 (80%) remained high-positive. In this study of antibody kinetics and durability following SARS-CoV-2 mRNA vaccination, 43% experienced an increase antibody titer, 35% decreased, and 21% remained stable between 1 and 3 mo postvaccination. Though only a small minority (4%) who had detectable antibody at 1 mo fell below the threshold of detectability at 3 mo, 19% with high-positive titers at 1 mo dropped to low-positive. In the mRNA-1273 trial, binding antibody levels declined slightly over time, but remained elevated at 3 mo after the completion of the 2-dose series.1 It is unknown if antibody decline over time results in higher risk of SARS-CoV-2 infection; however, these results raise the suggestion that additional booster dosing may help augment lower antibody responses in transplant recipients. This study is limited by convenience sampling, lack of immunocompetent control group, and lack of exploration of neutralizing antibody and memory B immune response. Also, despite clinical screening for incident symptomatic coronavirus disease 2019, antinucleocapsid testing was not performed, precluding analysis of asymptomatic exposure. In conclusion, we found that antispike antibody sero-response 3 mo following the mRNA vaccine series was largely stable. Understanding longitudinal kinetics of antibody decline among transplant recipients in the context of thresholds for protection may inform need and timing for booster vaccinations.

Impaired humoral immunity to SARS-CoV-2 BNT162b2 vaccine in kidney transplant recipients and dialysis patients.

Patients with kidney failure are at increased risk for SARS-CoV-2 infection making effective vaccinations a critical need. It is not known how well mRNA vaccines induce B and plasma cell responses in dialysis patients (DP) or kidney transplant recipients (KTR) compared to healthy controls (HC). We studied humoral and B cell responses of 35 HC, 44 DP and 40 KTR. Markedly impaired anti-BNT162b2 responses were identified among KTR and DP compared to HC. In DP, the response was delayed (3-4 weeks after boost) and reduced with anti-S1 IgG and IgA positivity in 70.5% and 68.2%, respectively. In contrast, KTR did not develop IgG responses except one patient who had a prior unrecognized infection and developed anti-S1 IgG. The majority of antigen-specific B cells (RBD+) were identified in the plasmablast or post-switch memory B cell compartments in HC, whereas RBD+ B cells were enriched among pre-switch and naïve B cells from DP and KTR. The frequency and absolute number of antigen-specific circulating plasmablasts in the cohort correlated with the Ig response, a characteristic not reported for other vaccinations. In conclusion, these data indicated that immunosuppression resulted in impaired protective immunity after mRNA vaccination, including Ig induction with corresponding generation of plasmablasts and memory B cells. Thus, there is an urgent need to improve vaccination protocols in patients after kidney transplantation or on chronic dialysis.

One-Stop Serum Assay Identifies COVID-19 Disease Severity and Vaccination Responses.

SARS-CoV-2 has caused over 100,000,000 cases and almost 2,500,000 deaths globally. Comprehensive assessment of the multifaceted antiviral Ab response is critical for diagnosis, differentiation of severity, and characterization of long-term immunity, especially as COVID-19 vaccines become available. Severe disease is associated with early, massive plasmablast responses. We developed a multiplex immunoassay from serum/plasma of acutely infected and convalescent COVID-19 patients and prepandemic and postpandemic healthy adults. We measured IgA, IgG, and/or IgM against SARS-CoV-2 nucleocapsid (N), spike domain 1 (S1), S1–receptor binding domain (RBD) and S1–N-terminal domain. For diagnosis, the combined [IgA + IgG + IgM] or IgG levels measured for N, S1, and S1-RBD yielded area under the curve values ≥0.90. Virus-specific Ig levels were higher in patients with severe/critical compared with mild/moderate infections. A strong prozone effect was observed in sera from severe/critical patients—a possible source of underestimated Ab concentrations in previous studies. Mild/moderate patients displayed a slower rise and lower peak in anti-N and anti-S1 IgG levels compared with severe/critical patients, but anti-RBD IgG and neutralization responses reached similar levels at 2–4 mo after symptom onset. Measurement of the Ab responses in sera from 18 COVID-19–vaccinated patients revealed specific responses for the S1-RBD Ag and none against the N protein. This highly sensitive, SARS-CoV-2–specific, multiplex immunoassay measures the magnitude, complexity, and kinetics of the Ab response and can distinguish serum Ab responses from natural SARS-CoV-2 infections (mild or severe) and mRNA COVID-19 vaccines.

IgG Antibodies against SARS-CoV-2 Correlate with Days from Symptom Onset, Viral Load and IL-10

Abstract The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a pandemic of coronavirus disease 2019 (COVID-19). Antibody testing is essential to identify persons exposed to the virus and potentially predicting immunity. 183 COVID-19 patients (68 mechanically ventilated) and 41 controls were tested for plasma IgG, IgA and IgM against the SARS-CoV-2 S1, S2, receptor binding domain (RBD) and N proteins using the MILLIPLEX® SARS-CoV-2 Antigen Panels. COVID-19 positive patients had high levels of IgG, IgA and IgM anti-SARS-CoV-2 antibodies against viral proteins. Sensitivity of anti-S1 IgG increased from 60% to 93% one week after symptom onset. S1-IgG and S1-IgA had specificities of 98%. Ventilated COVID-19 patients had higher antibody levels than the COVID-19 patients who were not ventilated. IgG antibody levels against S1 protein had the strongest correlation to days from symptom onset. We found that patients with the highest IgG levels had the lowest viral load. Finally, there was a correlation of high plasma IL-10 with low anti-SARS-CoV-2 IgG.

Heterogenous Serological Responses to BNT162b2 mRNA Vaccine in Patients with Haematological Malignancies

Background: Patients with active haematological malignancies (HM) have been excluded from clinical trials evaluating vaccines against SARS-CoV-2. Both HM and their treatments are commonly immunosuppressive and are likely to impact COVID-19 vaccine efficacy.Methods: We performed a study assessing serological response to one and two BNT162b2 vaccine doses in healthy healthcare workers (HCWs) and in patients with HM. Peripheral blood samples were collected at three time points: 0-10 days before the first BNT162b2 vaccine jab, on the day of second jab (around day 21) and 7 to 21 days after the second jab. Abbott Architect SARS-CoV-2 IgG Quant II assay was used to quantify serum anti-SARS-CoV-2-S1 IgG antibody (anti-S1 IgG) levels. HM individuals were stratified into groups by current or most recent treatment, latency since treatment and anti-S1 IgG seroconversion status before the first jab.Results: 653 anti-S1 IgG negative participants with HM (median age 64 years, IQR 53 - 72, 52% female) and 69 healthy HCWs (40 [32 - 53] years, 83% female) were included in the study. 18-60 year-old HM patients had lower median anti-S1 IgG response (median 6810 [IQR 635 - 20574] vs 21394 [14289 - 33322], pConclusion: Patients with HM mount blunted and heterogeneous antibody responses to full course of BNT162b2 mRNA vaccination. Patients actively treated with BTKi, ruxolitinib and anti-CD20 therapies appear to be the most negatively affected and may be left unprotected from COVID-19 infection. Regardless of seroconversion status before vaccination, many HM patients improve their serologic responses after the second BNT162b2 jab at 3 weeks.Funding Statement: This research is funded by the sponsor of our study - Vilnius University Hospital Santaros Klinikos.Declaration of Interests: We declare no competing interests.Ethics Approval Statement: The study was approved by the Vilnius Regional Bioethics Committee (approval No. 2021/3-1331-803).

Temporal development and neutralising potential of antibodies against SARS-CoV-2 in hospitalised COVID-19 patients: An observational cohort study.

Antibody responses are important in the control of viral respiratory infection in the human host. What is not clear for SARS-CoV-2 is how rapidly this response occurs, or when antibodies with protective capability evolve. Hence, defining the events of SARS-CoV-2 seroconversion and the time frame for the development of antibodies with protective potential may help to explain the different clinical presentations of COVID-19. Furthermore, accurate descriptions of seroconversion are needed to inform the best use of serological assays for diagnostic testing and serosurveillance studies. Here, we describe the humoral responses in a cohort of hospitalised COVID-19 patients (n = 19) shortly following the onset of symptoms. Commercial and ‘in-house’ serological assays were used to measure IgG antibodies against different SARS-CoV-2 structural antigens–Spike (S) S1 sub-unit and Nucleocapsid protein (NP)–and to assess the potential for virus neutralisation mediated specifically by inhibition of binding between the viral attachment protein (S protein) and cognate receptor (ACE-2). Antibody response kinetics varied amongst the cohort, with patients seroconverting within 1 week, between 1–2 weeks, or after 2 weeks, following symptom onset. Anti-NP IgG responses were generally detected earlier, but reached maximum levels slower, than anti-S1 IgG responses. The earliest IgG antibodies produced by all patients included those that recognised the S protein receptor-binding domain (RBD) and were capable of inhibiting binding to ACE-2. These data revealed events and patterns of SARS-CoV-2 seroconversion that may be important predictors of the outcome of infection and guide the delivery of clinical services in the COVID-19 response.

Antibody Responses One Year after Mild SARS-CoV-2 Infection.

Understanding the long-term kinetics of antibodies in coronavirus disease 2019 (COVID-19) is essential in interpreting serosurvey data. We investigated the antibody response one year after infection in 52 mildly symptomatic patients with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection, using three commercial immunoassays and a surrogate virus neutralization test (sVNT) kit. Anti-N pan-immunoglobulin (Ig), anti-S IgG, and anti-S1 IgG were detected in 43 (82.7%), 44 (84.6%), and 30 (57.7%), respectively. In 49 (94.2%), the antibody could be detected by either anti-N pan-Ig or anti-S IgG assay. In the sVNT, 30 (57.7%) had positive neutralizing activity. Despite waning immunity, SARS-CoV-2 antibodies can be detected up to one year after infection, even in mild COVID-19 patients.

Persistence of IgG response to SARS-CoV-2

Persistence of IgG response to SARS-CoV-2

Specific antibodies against the nucleocapsid protein and S1 domain of spike glycoprotein in patients with severe acute respiratory syndrome

To explore the laws of the appearance of the specific serum antibodies against the nucleocapsid (N) protein and the S1 domain of spike (S) glycoprotein in patients with severe acute respiratory syndrome (SARS) and to evaluate the value of these two proteins to be used as diagnostic makers for SARS. The serum samples of 86 patients with SARS confirmed clinically and serologically, 31 males and 55 females, aged 9 approximately 86, with the course of disease of 1 approximately 81 days, and 745 healthy persons were collected during the course. The specific immunoglobulin G (IgG) against N protein, IgG against S1 domain of S protein, and the SARS-CoV IgG in these sera were detected by ELISA. The positive rates of anti-N-IgG, anti S1-IgG, and anti-SARS-CoV IgG were 14% (6/44), 5% (2/44), and 14% (6/44) respectively in the first week of the course of disease, 56% (10/18), 39% (7/18), and 56% (10/18) respectively in the second week, and 100% (24/24), S1-IgG 83% (20/24), and 100% (24/24) respectively in the third week. The agreement rates of the results of anti-N-IgG and anti-s1-IgG with that of the anti-SARS-CoV IgG were 88% (76/86) and 83% (71/86) respectively. The anti-SARS-CoV IgG positive rate in the healthy persons was 1.88% (14.745). The N protein and S1 protein may be used as antigens in the development of serological assay for detection of SARS-CoV infection.