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1.
Iranian Journal of Kidney Diseases ; 16(4):259-265, 2022.
Article in English | GIM | ID: covidwho-2026841

ABSTRACT

Introduction. SARS-CoV-2 infection have been reported to have a greater mortality rate in adults receiving dialysis, as compared to general population. Hence, vaccination is very important in this vulnerable population group, in order to achieve an acceptable level of immunity. The aim of this study was to compare the level of anti-SARS-CoV-2 anti-spike protein receptor-binding domain IgG neutralizing antibody before and after vaccination with two doses of SinopharmR vaccine, in patients undergoing hemodialysis. Methods. Ninety patients on maintenance in-center hemodialysis received two doses of SinopharmR COVID-19 vaccine with an interval of about 28 days. Anti-SARS-CoV-2 anti-spike protein receptor-binding domain IgG (Anti-RBD) neutralizing antibody was measured with an ELISA kit. All statistical analyses were performed by SPSS-26 software. Results. The absolute mean (+or- SE) change in antibody titer following full-scheduled vaccination was 8.98 +or- 1.49 micro g/mL. The rate of seroconversion was 31.1% after two doses of vaccine. In addition, the rate of seroconversion was higher in those with a history of COVID-19 than in those without a history of COVID-19. Conclusion. Conclusion. The administration of booster doses, doubling of the dose in each episode of vaccination schedule as well as combination of different vaccine platforms are recommended to increase COVID-19 vaccine efficacy in hemodialysis patients.

2.
Clinical Laboratory ; 2022.
Article in English | Web of Science | ID: covidwho-2025359

ABSTRACT

Background: To assess protective immunity among a general population against severe acute respiratory syndrome coronavirus 2, the correlation of the commercially available solid-phase assay (SPA) for SARS-CoV-2 IgG with a neutralization assay must be investigated. Methods: Both the neutralization assay and SPA were performed on samples of 143 recovered coronavirus disease 2019 (COVID-19) patients. SARS-CoV-2 IgG was measured using two SPAs for the chemiluminescence immunoassay principle with different target proteins: nucleocapsid and spike protein (Architect i2000SR [Abbott] and Liaison XL [DiaSorin], respectively). The plaque reduction neutralization test (PRNT) was conducted to obtain titers for the neutralizing antibody. Results: All patients had PRNT titers ranging from 10 to 2,560. Spike Ab SPA had greater sensitivity than nucleocapsid Ab SPA (81.1% [116/143] and 70.6% [101/143], respectively, p = 0.003). The values measured for both SPAs had a positive correlation with the PRNT titers (both R = 0.77, p < 0.001). To predict a high PRNT titer (>= 160), cutoff values of two SPAs were adjusted based on receiver-operating characteristics curve analysis. The nucleocapsid Ab SPA (cutoff index of 4.17) attained 90.3% sensitivity and 75.9% specificity, whereas the spike Ab SPA (cutoff value of 109 unit/mL) attained 87.1% sensitivity and 89.3% specificity. Therefore, the spike Ab SPA had greater specificity than the nucleocapsid Ab SPA (p = 0.003). Conclusions: The qualitative SPA for nucleocapsid Ab, as well as the quantitative SPA for spike Ab, had a modest positive correlation with the neutralization assay. However, spike Ab SPA was more suitable for neutralizing capacity.

3.
Bratislavske Lekarske Listy ; 123(9):631-633, 2022.
Article in English | MEDLINE | ID: covidwho-2024874

ABSTRACT

Many of the deletions and large mutations found in the Omicron version of COVID-19 are identical to those seen in the alpha, pi, beta, and delta based VOCs. Such deletions and alterations have long been known to increase the viral risk of transmission and binding ability. Additionally, these changes are anticipated to increase the chances of immunological evasion and antibody secretion. T478K, G339D, Y505H, S373P, S371L, S375F, N440K, K417N, S477N, G446S, Q493R, E484A, G496S, N501Y, Q498R, and D614G are all mutations that potentially affect the virus's behavior. The N terminal region of the spike is typically targeted by NABs or neutralizing antibodies, immunologic polypeptides that prevent viruses from infecting cells. If the target region of the NABs significantly alters, the viruses may be able to avoid the autoimmune response generated by initial infection and vaccination. A possible "receptor shift" wherein ACE2 is not exclusively an Omicron receptor is worrying, given the huge number of mutations within the RBD region. D614G is the most prevalent mutation discovered among the three major pandemic variants. The Omicron variant is the most divergent variation seen in large numbers thus far in the pandemic, raising concerns that it could be linked to a faster transmission rate, lower vaccine effectiveness, and a greater risk of re-infection. Since identifying the Omicron variant, various countries have made significant modifications to their vaccination programs, including the recommendation of a third injection of boosting vaccination dosages in large populations to reduce the risk of adverse effects. However, all three vaccine producers (Johnson et Johnson, BioNTech, Pfizer, and Moderna) have published statements claiming vaccines would protect against severe sickness and that variant-specific vaccinations and boosters are in the works. This review sheds insight on several genetic mutations and their evolution in distinct variations. However, further study is needed to improve our understanding of illness transmissibility, immune escape capacity, patient features and severity, and the use of further diagnostic and therapeutic techniques (Fig. 1, Ref. 20). Keywords: SARS-CoV-2, global vaccination, booster doses, COVID-19.

4.
Zoonoses (Burlingt) ; 2(1)2022.
Article in English | MEDLINE | ID: covidwho-2025750

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused global destruction since its emergence in late 2019. Over the past two years, the virus has continuously evolved in human host, leading to emergence of variants with changed viral transmission, disease severity, and evasion of immunity. Although vaccines have been developed for the coronavirus disease 2019 (COVID-19) at an unprecedently pace, the variants have constantly posed threats to the effectiveness of the approved vaccines. In this short communication, we review the key variants and discuss their implications in viral replication, transmission, and immune evasion.

5.
Atmosphere ; 13(8):1199, 2022.
Article in English | ProQuest Central | ID: covidwho-2023113

ABSTRACT

To date, research regarding the changes of the sulfur and nitrogen rates in Wuhan during the summer is limited. In this study, we analyzed the air quality in Wuhan, China, using water-soluble ion, gaseous precursor, and weather data. A Spearman correlation analysis was then performed to investigate the temporal changes in air quality characteristics and their driving factors to provide a reference for air pollution control in Wuhan. The results indicate that SO2 in the atmosphere at Wuhan undergoes secondary conversion and photo-oxidation, and the conversion degree of SO2 is higher than that of NO2. During the summers of 2016 and 2017, secondary inorganic atmospheric pollution was more severe than during other years. The fewest oxidation days occurred in summer 2020 (11 days), followed by the summers of 2017 and 2014 (25 and 27 days, respectively). During the study period, ion neutralization was the strongest in summer 2015 and the weakest in August 2020. The aerosols in Wuhan were mostly acidic and NH4+ was an important neutralizing component. The neutralization factors of all cations showed little change in 2015. K+, Mg2+, and Ca2+ level changes were the highest in 2017 and 2020. At low temperature, high humidity, and low wind speed conditions, SO2 and NO2 were more easily converted into SO42− and NO3−.

6.
Frontiers in Immunology ; 13, 2022.
Article in English | Web of Science | ID: covidwho-2022731

ABSTRACT

To cope with the decline in COVID-19 vaccine-induced immunity caused by emerging SARS-CoV-2 variants, a heterologous immunization regimen using chimpanzee adenovirus vectored vaccine expressing SARS-CoV-2 spike (ChAd-S) and an inactivated vaccine (IV) was tested in mice and non-human primates (NHPs). Heterologous regimen successfully enhanced or at least maintained antibody and T cell responses and effectively protected against SARS-CoV-2 variants in mice and NHPs. An additional heterologous booster in mice further improved and prolonged the spike-specific antibody response and conferred effective neutralizing activity against the Omicron variant. Interestingly, priming with ChAd-S and boosting with IV reduced the lung injury risk caused by T cell over activation in NHPs compared to homologous ChAd-S regimen, meanwhile maintained the flexibility of antibody regulation system to react to virus invasion by upregulating or preserving antibody levels. This study demonstrated the satisfactory compatibility of ChAd-S and IV in prime-boost vaccination in animal models.

7.
Clin Infect Dis ; 2021 Dec 10.
Article in English | MEDLINE | ID: covidwho-2017793

ABSTRACT

BACKGROUND: People living with HIV (PLWH) have been reported to have a higher risk of more severe Covid-19 disease and death. We assessed the ability of the Ad26.CoV2.S vaccine to elicit neutralizing activity against the Delta variant in PLWH relative to HIV-negative individuals. We also examined effects of HIV status and suppression on Delta neutralization response in SARS-CoV-2 infected unvaccinated participants. METHODS: We enrolled participants who vaccinated through the SISONKE South African clinical trial of the Ad26.CoV2.S vaccine in health care workers (HCW). PLWH in this group had well controlled HIV infection. We also enrolled unvaccinated participants previously infected with SARS-CoV-2. Neutralization capacity was assessed by a live virus neutralization assay of the Delta variant. RESULTS: Majority of Ad26.CoV2.S vaccinated HCW were previously infected with SARS-CoV-2. In this group, Delta variant neutralization was 9-fold higher compared to the infected only group and 26-fold higher relative to the vaccinated only group. No decrease in Delta variant neutralization was observed in PLWH relative to HIV-negative participants. In contrast, SARS-CoV-2 infected, unvaccinated PLWH showed 7-fold lower neutralization and a higher frequency of non-responders, with the highest frequency of non-responders in people with HIV viremia. Vaccinated only participants showed low neutralization capacity. CONCLUSIONS: The neutralization response of the Delta variant following Ad26.CoV2.S vaccination in PLWH with well controlled HIV was not inferior to HIV-negative participants, irrespective of past SARS-CoV-2 infection. In SARS-CoV-2 infected and non-vaccinated participants, HIV infection reduced the neutralization response to SARS-CoV-2, with the strongest reduction in HIV viremic individuals.

8.
Microbiol Spectr ; : e0212922, 2022.
Article in English | PubMed | ID: covidwho-2019796

ABSTRACT

The SARS-CoV-2 Omicron variant is characterized by substantial changes in the antigenic structure of the Spike (S) protein. Therefore, antibodies induced by primary Omicron infection lack neutralizing activity against earlier variants. In this study, we analyzed whether these antigenic changes impact the sensitivity of commercial anti-SARS-CoV-2 antibody assays. Sera from 37 unvaccinated, convalescent individuals after putative primary Omicron infection were tested with a panel of 20 commercial anti-SARS-CoV-2 immunoassays. As controls, we used samples from 43 individuals after primary infection with the SARS-CoV-2 ancestral wild-type strain. In addition, variant-specific live-virus neutralization assays were used as a reference for the presence of SARS-CoV-2-specific antibodies in the samples. Notably, in Omicron convalescents, there was a statistically significant reduction in the sensitivity of all antibody assays containing S or its receptor-binding-domain (RBD) as antigens. Furthermore, antibody levels quantified by these assays displayed a weaker correlation with Omicron-specific neutralizing antibody titers than with those against the wild type. In contrast, the sensitivity of nucleocapsid-protein-specific immunoassays was similar in wild-type and Omicron-infected subjects. In summary, the antigenic changes in the Omicron S lead to reduced immunoreactivity in the current commercial S- and RBD-specific antibody assays, impairing their diagnostic performance. IMPORTANCE This study demonstrates that the antigenic changes of the SARS-CoV-2 Omicron variant affect test results from commercial Spike- and RBD-specific antibody assays, significantly diminishing their sensitivities and diagnostic abilities to assess neutralizing antibodies.

9.
10.
Clin Infect Dis ; 2022 Jan 17.
Article in English | MEDLINE | ID: covidwho-2017815

ABSTRACT

While SARS-CoV-2 vaccines prevent severe disease effectively, post-vaccination 'breakthrough' COVID-19 infections and transmission among vaccinated individuals remain ongoing concerns. We present an in-depth characterization of transmission and immunity among vaccinated individuals in a household, revealing complex dynamics and unappreciated comorbidities, including autoimmunity to type1 interferon in the presumptive index case.

11.
J Clin Immunol ; 2022.
Article in English | Web of Science | ID: covidwho-2014278

ABSTRACT

Reliable immunoassays are essential to early predict and monitor vaccine efficacy against SARS-CoV-2. The performance of an Interferon Gamma Release Assay (IGRA, QuantiFERON(R) SARS-CoV-2), and a current anti-spike serological test, compared to a plaque reduction neutralization test (PRNT) taken as gold standard were compared. Eighty vaccinated individuals, whose 16% had a previous history of COVID-19, were included in a longitudinal prospective study and sampled before and two to four weeks after each dose of vaccine. In non-infected patients, 2 doses were required for obtaining both positive IGRA and PRNT assays, while serology was positive after one dose. Each dose of vaccine significantly increased the humoral and cellular response. By contrast, convalescent subjects needed a single dose of vaccine to be positive on all 3 tests. Both IGRA and current serology assay were found predictive of a positive titer of neutralizing antibodies that is correlated with vaccine protection. Patients over 65 or 80 years old had a significantly reduced response. The response tended to be better with the heterologous scheme (vs. homologous) and with the mRNA-1273 vaccine (vs. BNT162b2) in the homologous group, in patients under 55 and under 65 years old, respectively. Finally, decrease intensity or absence of IGRA response and to a less extent of anti-spike serology were also correlated to reinfection which has occurred during the follow up. In conclusion, both IGRA and current anti-spike serology assays could be used at defined thresholds to monitor the vaccine response against SARS-CoV-2 and to simply identify non-responding individuals after a complete vaccination scheme. Two available specific tests (IGRA and anti-spike antibodies) could early assess the vaccine-induced immunity against SARS-CoV-2 at the individual scale, to potentially adapt the vaccination scheme in non-responder patients.

12.
Int J Infect Dis ; 122: 576-584, 2022 Jul 08.
Article in English | MEDLINE | ID: covidwho-2015433

ABSTRACT

OBJECTIVES: Observing the serological cross-reactivity between SARS-CoV-2 and dengue virus (DV), we aimed to elucidate its effect on dengue serodiagnosis and infectivity in a highly dengue-endemic city in India. METHODS: A total of 52 COVID-19 (reverse transcription-polymerase chain reaction [RT-PCR] positive) serum samples were tested in rapid lateral flow immunoassays and DV immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) to detect DV or SARS-CoV-2 IgG/immunoglobulin M. The COVID-19 antibody (Ab) positive samples were subjected to a virus neutralization test (Huh7 cells) using DV type 1 (DV1) clinical isolate. RESULTS: Most (93%) of the SARS-CoV-2 Ab-positive serum samples cross-reacted with DV in rapid or ELISA tests. All were DV RNA and nonstructural protein 1 (NS1) antigen-negative. COVID-19 serum samples that were DV cross-reactive neutralized DV1. Of these, 57% had no evidence of DV pre-exposure (DV NS1 Ab-negative). The computational study also supported potential interactions between SARS-CoV-2 Ab and DV1. CONCLUSION: DV serodiagnosis will be inconclusive in areas co-endemic for both viruses. The COVID-19 pandemic appears to impart a protective response against DV in DV-endemic populations.

13.
Clin Infect Dis ; 2021 Nov 10.
Article in English | MEDLINE | ID: covidwho-2008527

ABSTRACT

BACKGROUND: The factors associated with severe acute respiratory coronavirus 2 (SARS-CoV-2) reinfection remain poorly defined. METHODS: We identified patients with SARS-CoV-2 infection and at least one repeat reverse transcription (RT) - polymerase chain reaction (PCR) result a minimum of 90 days after the initial positive test and prior to January 21, 2021. Those with a repeat positive test were deemed to have reinfection (n = 75), and those with only negative tests were classified as convalescents (n = 1,594). Demographics, coronavirus disease 2019 (COVID-19) severity, and treatment histories were obtained from the Boston Medical Center electronic medical record. Humoral responses were analyzed using SARS-CoV-2 specific enzyme linked immunosorbent assays and pseudovirus neutralizations in subset of reinfection (n = 16) and convalescent samples (n = 32). Univariate, multivariate, and time to event analyses were used to identify associations. RESULTS: Individuals with reinfection had more frequent testing at shorter intervals compared to the convalescents. Unstable housing was associated with more than two-fold greater chance of reinfection. Pre-existing comorbidities and COVID-19 severity after the initial infection were not associated with reinfection. SARS-CoV-2 IgG levels and pseudovirus neutralization were not different within the early weeks after primary infection and at a time-point at least 90 days later in the two groups. In the convalescents, but not in those with reinfection, the late as compared to early humoral responses were significantly higher. CONCLUSIONS: Reinfection associates with unstable housing, which is likely a marker for virus exposure, and reinfection occurs in the presence of SARS-CoV-2 antibodies.

14.
Annals of the Rheumatic Diseases ; 81:938-939, 2022.
Article in English | EMBASE | ID: covidwho-2008904

ABSTRACT

Background: The impact of immunosuppressants on COVID-19 vaccination response and durability in patients with immune-mediated infammatory diseases (IMID) is yet to be fully characterized. Humoral response may be attenuated in these patients especially those on B cell depleting therapy and higher doses of corticosteroids, but data regarding other immunosuppressants are scarce. Objectives: We aimed to investigate antibody and T cell responses and durability to SARS-CoV-2 mRNA vaccines (BNT162b and/or mRNA 1273) in IMID patients on immunomodulatory maintenance therapy other than B-cell depleting therapy and corticosteroids. Methods: This prospective observational cohort study examined the immuno-genicity of SARS-CoV-2 mRNA vaccines in adult patients with IMIDs (psoriatic arthritis, psoriasis, infammatory bowel disease and rheumatoid arthritis) with or without maintenance immunosuppressive therapies (anti-TNF, methotrexate/azathioprine [MTX/AZA], anti-TNF + MTX/AZA, anti IL12/23, anti-IL-17, anti-IL23) compared to healthy controls. Automated ELISA for IgGs to spike trimer, spike receptor binding domain (RBD) and the nucleocapsid (NP) and T-cell release of 9 cytokines (IFNg, IL2, IL4, IL17A, TNF) and cytotoxic molecules (sFasL, GzmA, GzmB, Perforinin) in cell culture supernatants following stimulation with spike or NP peptide arrays were conducted at 4 time points: T1=pre vaccination, T2=me-dian 26 days after dose 1, T3=median 16 days after dose 2 and T4=median 106 days after dose 2. Neutralization assays against four SARS-CoV-2 variants (wild type, delta, beta and gamma) were conducted at T3. Results: We followed 150 subjects: 26 healthy controls and 124 IMID patients: 9 untreated, 44 on anti-TNF, 16 on anti-TNF with MTX/AZA, 10 on anti-IL23, 28 on anti-IL12/23, 9 on anti-IL17, 8 on MTX/AZA (Table 1). Most patients mounted antibody and T cell responses with increases from dose 1 to dose 2 (100% sero-conversion at T3) and some decline by T4, with variability within groups. Antibody levels and neutralization efficacy was lower in anti-TNFgroups (anti-TNF, anti-TNF + MTX/AZA) compared to controls and waned by T4 (Figure 1). T cell responses were not consistently different between groups. Pooled data showed a higher antibody response to mRNA-1273 compared to BNT162b. Conclusion: Following 2 doses of mRNA vaccination there is 100% seroconver-sion in IMID patients on maintenance therapy. Antibody levels and neutralization efficacy in anti-TNF group are lower than controls, and wane substantially by 3 months after dose 2. These fndings highlight the need for third dose in patients undergoing treatment with anti-TNF therapy and continued monitoring of immunity in these patient groups, taking into consideration newer variants and additional vaccine doses.

16.
Cell Host & Microbe ; 2022.
Article in English | ScienceDirect | ID: covidwho-2007589

ABSTRACT

Summary The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariant BA.2.75 emerged recently and appears to be spreading. It has nine mutations in Spike compared to currently circulating BA.2, raising concerns it may further evade vaccine-elicited and therapeutic antibodies. We found BA.2.75 to be moderately more neutralization resistant to sera from vaccinated/boosted individuals than BA.2 (1.8-fold), similar to BA.2.12.1 (1.1-fold), but more neutralization sensitive than BA.4/5 (0.6-fold). Relative to BA.2, BA.2.75 showed heightened resistance to class 1 and class 3 monoclonal antibodies targeting the Spike receptor-binding domain, while gaining sensitivity to class 2 antibodies. Resistance was largely conferred by G446S and R460K mutations. BA.2.75 was slightly resistant (3.7-fold) to bebtelovimab, a therapeutic antibody with potent activity against all Omicron subvariants. BA.2.75 also exhibited higher binding affinity to host receptor ACE2 than other Omicron subvariants. BA.2.75 provides further insight into SARS-CoV-2 evolution as it gains transmissibility while incrementally evading antibody neutralization.

17.
Methods in Enzymology ; 2022.
Article in English | ScienceDirect | ID: covidwho-2007357

ABSTRACT

After more than two years, COVID-19 still represents a global health burden of unprecedented extent and assessing the degree of immunity of individuals against SARS-CoV-2 remains a challenge. Virus neutralization assays represent the gold standard for assessing antibody-mediated protection against SARS-CoV-2 in sera from recovered and/or vaccinated individuals. Neutralizing antibodies block the interaction of viral spike protein with human angiotensin-converting enzyme 2 (ACE2) receptor in vitro and prevent viral entry into host cells. Classical viral neutralization assays using full replication-competent viruses are restricted to specific biosafety level 3-certified laboratories, limiting their utility for routine and large-scale applications. We developed therefore a cell-fusion-based assay building on the interaction between viral spike and ACE2 receptor expressed on two different cell lines, substantially reducing biosafety risks associated with classical viral neutralization assays. This chapter describes this simple, sensitive, safe and cost-effective approach for rapid and high-throughput evaluation of SARS-CoV-2 neutralizing antibodies relying on high-affinity NanoLuc® luciferase complementation technology (HiBiT). When applied to a variety of standards and patient samples, this method yields highly reproducible results in 96-well, as well as in 384-well format. The use of novel NanoLuc® substrates with increased signal stability like Nano-Glo® Endurazine™ furthermore allows for high flexibility in assay set-up and full automatization of all reading processes. Lastly, the assay is suitable to evaluate the neutralizing capacity of sera against the existing spike variants, and potentially variants that will emerge in the future.

18.
Infect Dis Ther ; : 1-17, 2022.
Article in English | PMC | ID: covidwho-2007309

ABSTRACT

INTRODUCTION: AOD01 is a novel, fully human immunoglobulin (Ig) G1 neutralizing monoclonal antibody that was developed as a therapeutic against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). This first-in-human study assessed safety, tolerability, pharmacokinetics (PK), and pharmacodynamics of AOD01 in healthy volunteers. METHODS: Intravenous doses of AOD01 were evaluated in escalating cohorts [four single-dose cohorts (2, 5, 10, and 20 mg/kg) and one two-dose cohort (two doses of 20 mg/kg, 24 h apart)]. RESULTS: Twenty-three subjects were randomized to receive AOD01 or a placebo in blinded fashion. A total of 34 treatment-emergent adverse events (TEAEs) were reported;all were mild in severity. Related events (headache and diarrhea) were reported in one subject each. No event of infusion reactions, serious adverse event (SAE), or discontinuation due to AE were reported. The changes in laboratory parameters, vital signs, and electrocardiograms were minimal. Dose-related exposure was seen from doses 2 to 20 mg/kg as confirmed by Cmax and AUC0-tlast. The median Tmax was 1.5-3 h. Clearance was dose independent. Study results revealed long half-lives (163-465 h). Antidrug antibodies (ADA) to AOD01 were not detected among subjects, except in one subject of the two-dose cohort on day 92. Sustained ex vivo neutralization of SARS-CoV-2 was recorded until day 29 with single doses from 2 to 20 mg/kg and until day 43 with two doses of 20 mg/kg. CONCLUSIONS: AOD01 was safe and well tolerated, demonstrated dose-related PK, non-immunogenic status, and sustained ex vivo neutralization of SARS-CoV-2 after single intravenous dose ranging from 2 to 20 mg/kg and two doses of 20 mg/kg and show good potential for treatment of SARS-CoV-2 infection. (Health Sciences Authority identifier number CTA2000119).

19.
Gut ; 71:A36, 2022.
Article in English | EMBASE | ID: covidwho-2005346

ABSTRACT

Introduction Patients with inflammatory bowel disease (IBD) treated with anti-TNF therapy exhibit attenuated humoral immune responses to vaccination against SARS-CoV-2. The gut microbiota and its functional metabolic output, which are perturbed in IBD, play an important role in shaping host immune responses. We explored whether the gut microbiota and metabolome could explain variation in anti-SARS-CoV-2 vaccination responses in immunosuppressed IBD patients. Methods Faecal and serum samples were prospectively collected from patients with IBD established on infliximab therapy (for >12 weeks) who were undergoing vaccination against SARS-CoV-2. The Roche Elecsys Anti-SARS-CoV-2 spike (S) and nucleocapsid (N) immunoassays were used to measure antibody responses following two doses of either ChAdOx1 nCoV-19 or BNT162b2 vaccine. Seroconversion was defined by a cut-off anti-S concentration of 15 U/ml, which correlated with 20% viral neutralization;anti-S antibody concentration of < 380 U/ml was indicative of poor response to vaccination. Patients with serological evidence of prior SARS-CoV-2 infection were excluded from the analysis. Faecal calprotectin measurement, 16S rRNA gene amplicon sequencing, nuclear magnetic resonance (NMR) spectroscopy and bile acid profiling with ultra-performance liquid chromatography mass spectrometry (UPLC-MS) were performed on faecal samples. Results Forty-five infliximab-treated patients were recruited (median age 40 [range 19-67];32 Crohn's disease, 13 ulcerative colitis;28 with concomitant immunomodulator therapy;six with prior infection). 14 patients (35%) had seroconverted after one dose of vaccine and 37 (95%) seroconverted after two doses. 18 patients (46%) had a poor response after two doses of vaccine. There was no association between faecal calprotectin and vaccine response (p=0.41). No differences between satisfactory and poor vaccine responders were noted in alpha or beta diversity of the gut microbiota. The faecal metabolome of satisfactory responders was enriched in the microbial metabolite trimethylamine (q=0.03). Trends were noted linking the short chain fatty acid butyrate with satisfactory response (P=0.01) and succinate with poor response (P=0.06). No significant differences in primary or secondary bile acids were found to associate with vaccine response. The butyrate-producing genus Roseburia was positively correlated with faecal butyrate abundance (q=0.03). Conclusions Our data suggest an association between gut microbiota function and variable serological response to vaccination against SARS-CoV-2 in immunocompromised patients. Microbial metabolites including trimethylamine and butyrate may be important in mitigating anti-TNF-induced attenuation of the immune response.

20.
Vaccine ; 2022.
Article in English | ScienceDirect | ID: covidwho-2004590

ABSTRACT

Respiratory transmission of SARS-CoV-2 is considered to be the major dissemination route for COVID-19, therefore, mucosal immune responses have great importance in preventing SARS-CoV-2 from infection. In this study, we constructed a recombinant Vaccinia virus (VV) harboring trimeric receptor-binding domain (RBD) of SARS-CoV-2 spike protein (VV-tRBD), and evaluated the immune responses towards RBD following intranasal immunization against mice and rabbits. In BALB/c mice, intranasal immunization with VV-tRBD elicited robust humoral and cellular immune responses, with high-level of both neutralizing IgG and IgA in sera against SARS-CoV-2 psudoviruses, and a number of RBD-specific IFN-γ-secreting lymphocytes. Sera from immunized rabbits also exhibited neutralization effects. Notably, RBD-specific secretory IgA (sIgA) in both nasal washes and bronchoalveolar lavage fluids (BALs) were detectable and showed substantial neutralization activities. Collectively, a recombinant VV expressing trimeric RBD confers robust systemic immune response and mucosal neutralizing antibodies, thus warranting further exploration as a mucosal vaccine.

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