Reduced Antibody Response Research Articles

Robust immune response to COVID-19 vaccination in the island population of Greenland

BackgroundIn Greenland, the COVID-19 pandemic was characterised by a late onset of community transmission and a low impact on the healthcare system, hypothesised as being partly due to a high uptake of vaccinations. To underpin this description, we aimed to assess the SARS-CoV-2 immune response post-vaccination in a Greenlandic population.MethodsIn this observational cohort study, we included 430 adults in Greenland who had received a complete two-dose SARS-CoV-2 vaccination at enrolment. The total plasma SARS-CoV-2 spike glycoprotein Ig antibodies (S-Ab) induced by either the BNT162b2 or mRNA-1273 vaccine, was measured up to 11 months after the second vaccine dose. In addition, total salivary S-Abs were examined in 107 participants, and the T-cell response to the spike glycoprotein was assessed in 78 participants out of the entire study cohort.ResultsHere we demonstrate that two months after the second vaccine dose, 96% of participants have protective plasma S-Ab levels. By 11 months, 98% have protective levels, with prior SARS-CoV-2 infection particularly enhancing S-Ab levels by 37% (95% CI 25–51%). Among individuals aged 60 years and older, we observe a 21% (95% CI 7–33%) reduction in antibody response. Total salivary S-Ab levels are detectable in all participants and significantly correlate with plasma levels. Moreover, all participants exhibit a robust SARS-CoV-2-specific T-cell response 11 months post-primary vaccination.ConclusionsOur findings show that Greenlanders exhibit a robust and lasting immune response, both humoral and cellular, comparable to other population groups up to at least 11 months after the second vaccine dose. These results corroborate the hypothesis that vaccines contributed to the mild impact of the COVID-19 pandemic in the Greenlandic population.

Immunogenicity and safety of different combinations involving a third booster dose of SARS-CoV-2 inactivated vaccine, inactivated quadrivalent influenza vaccine, and 23-valent pneumococcal polysaccharide vaccine in adults aged ≥60 years: a phase 4, randomized, open-label study.

Concomitant administration of COVID-19, influenza, and pneumococcal vaccines could reduce the burden on healthcare systems. However, the immunogenicity and safety of various combinations of a third booster dose of SARS-CoV-2 inactivated vaccine (CoronaVac), inactivated quadrivalent influenza vaccine (IIV4), and 23-valent pneumococcal polysaccharide vaccine (PPV23), particularly in different age groups, is still unknown. A phase 4, randomized, open-label, controlled trial was conducted in Beijing, China. 636 healthy adults were divided into two age groups (18-59 and ≥60 years) and randomized equally into three groups: CoronaVac and IIV4 followed by PPV23; CoronaVac and PPV23 followed by IIV4; or CoronaVac followed by IIV4 and PPV23, with a 28-day interval between vaccinations. Immunogenicity was evaluated by measuring antibody titers, and safety was monitored. ClinicalTrials.gov Identifier: NCT05298800. Co-administration of a third dose of CoronaVac, IIV4, and PPV23 in any combination was safe. Among adults aged 18-59, co-administration with PPV23 maintained non-inferiority of antibody levels for CoronaVac and IIV4, despite a slight reduction in antibody responses. This reduction was not observed in participants ≥60 years. Furthermore, co-administration of IIV4 and PPV23 affected seroconversion rates for both vaccines. Co-administration of the third dose of SARS-CoV-2 inactivated vaccine with the influenza vaccine, followed by PPV23, may be optimal for adults aged 18-59. In adults ≥60, all vaccine combinations were immunogenic, suggesting a flexible vaccination approach. Since antibody measurements were taken 28 days post-vaccination, ongoing surveillance is essential to assess the longevity of the immune responses.

Advancing PFAS risk assessment: Integrative approaches using agent-based modelling and physiologically-based kinetic for environmental and health safety

Per- and polyfluoroalkyl substances (PFAS), ubiquitous in a myriad of consumer and industrial products, and depending on the doses of exposure represent a hazard to both environmental and public health, owing to their persistent, mobile, and bio accumulative properties. These substances exhibit long half-lives in humans and can induce potential immunotoxic effects at low exposure levels, sparking growing concerns. While the European Food Safety Authority (EFSA) has assessed the risk to human health related to the presence of PFAS in food, in which a reduced antibody response to vaccination in infants was considered as the most critical human health effect, a comprehensive grasp of the molecular mechanisms spearheading PFAS-induced immunotoxicity is yet to be attained. Leveraging modern computational tools, including the Agent-Based Model (ABM) Universal Immune System Simulator (UISS) and Physiologically Based Kinetic (PBK) models, a deeper insight into the complex mechanisms of PFAS was sought. The adapted UISS serves as a vital tool in chemical risk assessments, simulating the host immune system's reactions to diverse stimuli and monitoring biological entities within specific adverse health contexts. In tandem, PBK models unravelling PFAS' biokinetics within the body i.e. absorption, distribution, metabolism, and elimination, facilitating the development of time-concentration profiles from birth to 75 years at varied dosage levels, thereby enhancing UISS-TOX's predictive abilities. The integrated use of these computational frameworks shows promises in leveraging new scientific evidence to support risk assessments of PFAS. This innovative approach not only allowed to bridge existing data gaps but also unveiled complex mechanisms and the identification of unanticipated dynamics, potentially guiding more informed risk assessments, regulatory decisions, and associated risk mitigations measures for the future.

Neutralizing antibody responses against contemporary and future influenza A(H3N2) viruses in paradoxical clades elicited by repeated and single vaccinations.

As one of the most effective measures to prevent seasonal influenza viruses, annual influenza vaccination is globally recommended. Nevertheless, evidence regarding the impact of repeated vaccination to contemporary and future influenza has been inconclusive. A total of 100 subjects singly or repeatedly immunized with influenza vaccines including 3C.2a1 or 3C.3a1 A(H3N2) during 2018-2019 and 2019-2020 influenza season were recruited. We investigated neutralization antibody by microneutralization assay using four antigenically distinct A(H3N2) viruses circulating from 2018 to 2023, and tracked the dynamics of B cell receptor (BCR) repertoire for consecutive vaccinations. We found that vaccination elicited cross-reactive antibody responses against future emerging strains. Broader neutralizing antibodies to A(H3N2) viruses and more diverse BCR repertoires were observed in the repeated vaccination. Meanwhile, a higher frequency of BCR sequences shared among the repeated-vaccinated individuals with consistently boosting antibody response was found than those with a reduced antibody response. Our findings suggest that repeated seasonal vaccination could broaden the breadth of antibody responses, which may improve vaccine protection against future emerging viruses.

Diminished antibody response to SARS-CoV-2 in rheumatoid arthritis compared to metabolic disorders following the primary series of vaccinations and its recovery with a booster: A single-center prospective observational study.

To compare antibody responses after vaccinations between patients with rheumatoid arthritis (RA) and patients with metabolic disorders (MD). The study places special emphasis on understanding how common diseases affect antibody responses in individuals with RA within real-world settings. The participants were 117 patients with RA (66 with RA only and 51 with RA and MD) and 37 patients with MD who received both the primary series of vaccinations and a booster. Antibody titers were compared after the primary series of vaccinations and a booster, and factors influencing the antibody response were assessed. Following the primary series of vaccinations, a significant reduction in antibody titers was observed in patients with longer days between vaccination and antibody measurement, the use of IL-6 inhibitors, selective T cell co-stimulation modulators, and methotrexate. Comorbid MD did not exhibit significant influences on antibody response in RA. Notably, the presence of RA itself was not significant in multivariate linear regression analysis. After the administration of the booster, however, day between vaccination and antibody measurement, the use of IL-6 inhibitor, and methotrexate no longer remained significant. Only the use of selective T cell co-stimulation modulators retained its significance. MD did not exhibit a significant impact on antibody responses in RA patients. The reduced antibody response following the primary series in RA patients appeared to be attributed more to specific RA medications rather than to the disease itself. Booster vaccines are vital in restoring the antibody response in RA.

Informing the Need for a SARS-CoV-2 Booster Based on the Immune Responses Among Young Healthy Adults to Variants Circulating in Late 2023.

COVID-19 remains a global public health challenge due to new immune-evasive SARS-CoV-2 variants and heterogeneous immunity. In this cross-sectional study, we evaluated the adaptive immune responses in US active duty personnel who completed a COVID-19 primary vaccine series and had heterogenous SARS-CoV-2 vaccination and infection histories to 3 previously dominant variants (ancestral, Delta, BA.5) and 3 circulating variants (XBB.1.5, EG.5, and BA.2.86) in late 2023. Analyses were based on the most recent exposure in terms of timing (within or beyond 12 months) and type (vaccine or infection). Significant reduction was observed in binding antibodies, neutralization antibodies, memory B cells, and CD8+ T cells against circulating variants when compared with previous variants. The reduction in antibody response was more pronounced in those whose most recent exposure was >12 months from enrollment. In contrast, the CD4+ T-cell response was largely consistent across all tested variants. The type of most recent exposure was not a significant factor in determining the magnitude of current immune responses. Administration of the XBB.1.5-based booster is likely to enhance cross-reactive humoral responses against SARS-CoV-2 circulating lineages. Ongoing surveillance of immune responses to emerging variants is needed for informing vaccine composition and timing.

Longitudinal analysis of IAV-specific CD8+ T cell response to the high dose influenza vaccine (Fluzone) in healthy older adults

Abstract Influenza infection remains a leading cause of death among older adults worldwide. While vaccines offer an effective means of reducing the severity of influenza, their efficacy reduces in this demographic. To gain insight into the adaptive immune response, we conducted an analysis of antigen-specific CD8+ T cells before and after the administration of the high-dose seasonal influenza vaccine (Fluzone) over six seasons (2014, 2018, 2019, 2021, 2022, and 2023) in a cohort of healthy older adults (n=37, M=18, F=19, aged 72-92, spanning visits 1-3). Using the HAI assay, we observed seroconversion (a 4-fold antibody increase post-vaccination) for most strains (>67% of strains) in 46% of donors, for less than half of the strains (25-50% of strains) in 13% of donors, and no seroconversion (0% of strains) occurred in 30% of donors. Notably, there was a twofold higher occurrence of seroconversion for Influenza A virus (IAV) (51%) compared to Influenza B virus (IBV) (25%). As age advanced, 54% of donors exhibited a reduced antibody response, while 23% either experienced no change or saw an increase in their antibody response. Presently, we investigate the frequency and clonotype of influenza A virus (IAV) M1158-166-specific CD8+ T cells, tracking their changes post-vaccination and over a span of 1-5 years. This endeavor aims to uncover new insights into the molecular basis of the reduced antigen-specific CD8+ T cell response observed in certain older adults.

Safety and Immunogenicity of the mRNA-1273 Coronavirus Disease 2019 Vaccine in Solid Organ Transplant Recipients.

Solid organ transplant recipients (SOTRs) are at high risk for severe COVID-19. This open-label, phase 3b trial evaluated mRNA-1273 in 137 kidney and 77 liver SOTRs and 20 immunocompetent participants. In part A, SOTRs received three 100-µg doses of mRNA-1273; immunocompetent participants received 2 doses. In part B, an additional 100-µg dose was offered ≥4 months after the primary series. Here, we report interim trial results. mRNA-1273 was well-tolerated in SOTRs. Four serious adverse events were considered vaccine related by the investigator in 3 SOTRs with preexisting comorbidities. No vaccine-related biopsy-proven organ rejection events or deaths were reported. mRNA-1273 elicited modest neutralizing antibody responses after dose 2 and improved responses after dose 3 in SOTRs. Post-dose 3 responses among liver SOTRs were comparable to post-dose 2 responses in immunocompetent participants. Post-additional dose responses were increased in SOTRs, regardless of primary series vaccination. In liver SOTRs, post-additional dose responses were ∼3-fold higher versus post-dose 2 but lower than immunocompetent participant responses. Most kidney SOTRs received multiple immunosuppressants and had reduced antibody responses versus liver SOTRs. mRNA-1273 was well-tolerated, and dose 3 and the additional dose improved antibody responses among SOTRs. NCT04860297.

Determination of in vitro immunotoxic potencies of a series of perfluoralkylsubstances (PFASs) in human Namalwa B lymphocyte and human Jurkat T lymphocyte cells.

Exposure to PFASs is associated to several adverse health effects, such as immunotoxicity. Immunotoxic effects of PFOA and PFOS, including a reduced antibody response in both experimental animals and humans, have been reported. However, there is limited understanding of the underlying mechanisms involved. Moreover, there is only a restricted amount of immunotoxicity data available for a limited number of PFASs. In the current study the effects of 15 PFASs, including short- and long-chain perfluorinated carboxylic and sulfonic acids, fluorotelomer alcohols, and perfluoralkyl ether carboxylic acids were studied on the expression of recombinant activating gene 1 (RAG1) and RAG2 in the Namalwa human B lymphoma cell line, and on the human IL-2 promotor activity in Jurkat T-cells. Concentration-response data were subsequently used to derive in vitro relative potencies through benchmark dose analysis. In vitro relative potency factors (RPFs) were obtained for 6 and 9 PFASs based on their effect on RAG1 and RAG2 gene expression in Namalwa B-cells, respectively, and for 10 PFASs based on their inhibitory effect on IL-2 promotor activity in Jurkat T-cells. The most potent substances were HFPO-TA for the reduction of RAG1 and RAG2 gene expression in Namalwa cells (RPFs of 2.1 and 2.3 respectively), and PFDA on IL-2 promoter activity (RPF of 9.1). RAG1 and RAG2 play a crucial role in V (D)J gene recombination, a process for acquiring a varied array of antibodies crucial for antigen recognition. Hence, the effects observed in Namalwa cells might indicate a PFAS-induced impairment of generating a diverse range of B-cells essential for antigen recognition. The observed outcomes in the Jurkat T-cells suggest a possible PFAS-induced reduction of T-cell activation, which may contribute to a decline in the T-cell dependent antibody response. Altogether, the present study provides potential mechanistic insights into the reported PFAS-induced decreased antibody response. Additionally, the presented in vitro models may represent useful tools for assessing the immunotoxic potential of PFASs and prioritization for further risk assessment.

Naturally acquired adaptive immunity to Streptococcus pneumoniae is impaired in rheumatoid arthritis patients.

Patients with rheumatoid arthritis (RA) have an increased susceptibility to infections, including those caused by Streptococcus pneumoniae. Why RA is associated with increased susceptibility to S. pneumoniae is poorly understood. This study aims to assess the effects of RA and B-cell depletion therapy on naturally acquired antibody responses to 289 S. pneumoniae protein antigens using a novel protein array. IgG responses to S. pneumoniae were characterised in serum from RA patients and disease controls (myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)) using whole-cell ELISA, a flow cytometry opsonisation assay and an S. pneumoniae protein array. For the RA patients, results were compared before and after B-cell depletion therapy. Compared to a well-characterised disease control group of ME/CFS patients, RA patients had reduced antibody responses to multiple S. pneumoniae protein antigens, with significant IgG recognition of approximately half the number of antigens along with reduced median strengths of these responses. Reduction in multiple array antigen-specific responses also correlated with reduced IgG opsonisation of S. pneumoniae. Although B-cell depletion therapy with rituximab did not reduce overall IgG recognition of S. pneumoniae in the RA group, it was associated with marked disruption of pre-existing IgG repertoire to protein antigens in individual patients. These data show RA is associated with major disruption of naturally acquired adaptive immunity to S. pneumoniae, which can be assessed rapidly using a protein antigen array and is likely to contribute towards the increased incidence of pneumonia in patients with RA.

Immunogenicity and risk factors for poor humoral immune response to SARS-CoV-2 vaccine in patients with autoimmune hepatitis: a systematic review and meta-analysis.

Research on the immunogenicity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in patients with autoimmune hepatitis (AIH) has produced varied results, and the determinants of the immunological response remain largely elusive. A comprehensive search of three primary databases (PubMed, Embase, and Web of Science) yielded pertinent studies on the topic. The data extraction was a collaborative effort among three independent researchers, who subsequently reconvened to validate the key data that were collated. The primary outcomes were the magnitudes of humoral and cellular immune responses to the vaccines. The secondary outcomes were related to factors affecting the humoral immune response post-vaccination. Our systematic review incorporated eight studies, and the meta-analysis involved three. The average antibody response rates after one, two, and three doses of the SARS-CoV-2 vaccine were 86%, 82%, and 91%, respectively. Unexpectedly, the antibody concentrations of seropositive patients were markedly lower than those of their healthy counterparts. The cellular immune response rates after two and three vaccine doses were 74% and 56%, respectively. Treatment with mycophenolate mofetil and corticosteroids was associated with a notable decrease in seropositivity [pooled odds ratio (95% confidence interval): 2.62 (2.12-3.25) and 2.4 (1.51-3.82), respectively]. In contrast, azathioprine had no discernable impact on the humoral response. In patients with AIH, the immune response to COVID-19 vaccination is attenuated. Specific immunosuppressive agents, such as steroids and MMF, have been found to reduce antibody responses. Recognizing these determinants is foundational to formulating individualized vaccination strategies for patients with AIH. Further research with an emphasis on post-vaccination cellular immunity will be essential to refine the vaccination approaches for this demographic.

Early-life exposure to perfluoroalkyl substances and serum antibody concentrations towards common childhood vaccines in 18-month-old children in the Odense Child Cohort

Exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with reduced antibody response to childhood vaccinations. Previous studies have mostly focused on antibodies against diphtheria or tetanus, while fewer studies have assessed antibodies toward attenuated viruses, such as measles, mumps or rubella (MMR). Therefore, we set out to determine associations between prenatal and early postnatal PFAS exposure and vaccine-specific Immunoglobulin G (IgG) in the background-exposed Odense Child Cohort. Blood samples were drawn in pregnancy at gestation weeks 8–16 and from the offspring at age 18 months. In the maternal serum samples we quantified perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA). In the offspring serum samples we quantified the same five PFAS compounds and IgG towards diphtheria, tetanus and MMR. A total of 880 and 841 children were included in the analyses of diphtheria and tetanus or MMR, respectively. Multiple linear regression models were used for estimation of difference in virus-specific IgG per doubling of PFAS concentrations. Maternal PFAS concentrations were non-significantly inversely associated with most vaccine-specific antibody concentrations. Likewise, child PFAS concentrations were associated with non-significant reductions of antibodies towards tetanus and MMR. A significant reduction in the percent difference in mumps antibody concentration per doubling of child PFNA (−9.2% (95% confidence interval: −17.4;-0.2)), PFHxS (−8.3% (−15.0;-1.0) and PFOS (−7.9% (−14.8;-0.4) was found. These findings are of public health concern, as inadequate response towards childhood vaccines may represent a more general immune dysfunction.

Influenza A(H3N2) Antibody Responses to Standard-Dose Versus Enhanced Influenza Vaccine Immunogenicity in Older Adults and Prior Season's Vaccine Status.

Annual influenza vaccination is recommended for older adults but repeated vaccination with standard-dose influenza vaccine has been linked to reduced immunogenicity and effectiveness, especially against A(H3N2) viruses. Community-dwelling Hong Kong adults aged 65-82 years were randomly allocated to receive 2017-2018 standard-dose quadrivalent, MF59-adjuvanted trivalent, high-dose trivalent, and recombinant-HA quadrivalent vaccination. Antibody response to unchanged A(H3N2) vaccine antigen was compared among participants with and without self-reported prior year (2016-2017) standard-dose vaccination. Mean fold rise (MFR) in antibody titers from day 0 to day 30 by hemagglutination inhibition and virus microneutralization assays were lower among 2017-2018 standard-dose and enhanced vaccine recipients with (range, 1.7-3.0) versus without (range, 4.3-14.3) prior 2016-2017 vaccination. MFR was significantly reduced by about one-half to four-fifths for previously vaccinated recipients of standard-dose and all 3 enhanced vaccines (β range, .21-.48). Among prior-year vaccinated older adults, enhanced vaccines induced higher 1.43 to 2.39-fold geometric mean titers and 1.28 to 1.74-fold MFR versus standard-dose vaccine by microneutralization assay. In the context of unchanged A(H3N2) vaccine strain, prior-year vaccination was associated with reduced antibody response among both standard-dose and enhanced influenza vaccine recipients. Enhanced vaccines improved antibody response among older adults with prior-year standard-dose vaccination.

Clinical and immunological responses to COVID-19 vaccination in rheumatoid arthritis patients on disease modifying antirheumatic drugs: a cross-sectional study.

This study was conducted to investigate the immunological and clinical response to COVID-19 vaccination in rheumatoid arthritis (RA) patients receiving disease modifying antirheumatic drugs (DMARDs). A cross-sectional study was conducted among RA patients who received two doses of COVID-19 vaccine within 6 months to one year. Demographic information, comorbidities, vaccination details, and past COVID-19 infection details were collected. Hemoglobin (Hb), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and interleukin-6 (IL-6) levels were estimated. Disease Activity Score-28 (DAS-28) was calculated for RA patients. Anti-spike antibody (ASA) concentrations were measured, and compared with a healthy control population. Correlations of ASA with age, sex, disease parameters, medication use, and comorbidities were assessed. A total of 103 RA patients and 185 controls were included in the study. RA patients had higher mean age, lower mean Hb, higher ESR, and elevated IL-6 levels. Both groups showed positive results for anti-spike antibodies, with a higher percentage in controls. Among RA patients majority had low DAS-28 score. The number of DMARDs used showed a negative correlation with antibody levels. There was a slight positive correlation between ASA concentration and DAS-28 score. Comorbidities did not significantly influence antibody concentration. No significant differences were found in antibody levels based on the type of COVID-19 vaccine or previous COVID-19 infection or booster dose vaccination among RA patients. The study revealed that RA patients showed a reduced antibody response following COVID-19 vaccination compared to the control group and potentially influenced by immunosuppressive treatments and disease-related factors.

Antibody Responses to Influenza Vaccination are Diminished in Patients With Inflammatory Bowel Disease on Infliximab or Tofacitinib.

We sought to determine whether six commonly used immunosuppressive regimens were associated with lower antibody responses after seasonal influenza vaccination in patients with inflammatory bowel disease [IBD]. We conducted a prospective study including 213 IBD patients and 53 healthy controls: 165 who had received seasonal influenza vaccine and 101 who had not. IBD medications included infliximab, thiopurines, infliximab and thiopurine combination therapy, ustekinumab, vedolizumab, or tofacitinib. The primary outcome was antibody responses against influenza/A H3N2 and A/H1N1, compared to controls, adjusting for age, prior vaccination, and interval between vaccination and sampling. Lower antibody responses against influenza A/H3N2 were observed in patients on infliximab (geometric mean ratio 0.35 [95% confidence interval 0.20-0.60], p = 0.0002), combination of infliximab and thiopurine therapy (0.46 [0.27-0.79], p = 0.0050), and tofacitinib (0.28 [0.14-0.57], p = 0.0005) compared to controls. Lower antibody responses against A/H1N1 were observed in patients on infliximab (0.29 [0.15-0.56], p = 0.0003), combination of infliximab and thiopurine therapy (0.34 [0.17-0.66], p = 0.0016), thiopurine monotherapy (0.46 [0.24-0.87], p = 0.017), and tofacitinib (0.23 [0.10-0.56], p = 0.0013). Ustekinumab and vedolizumab were not associated with reduced antibody responses against A/H3N2 or A/H1N1. Vaccination in the previous year was associated with higher antibody responses to A/H3N2. Vaccine-induced anti-SARS-CoV-2 antibody concentration weakly correlated with antibodies against H3N2 [r = 0.27; p = 0.0004] and H1N1 [r = 0.33; p < 0.0001]. Vaccination in both the 2020-2021 and 2021-2022 seasons was associated with significantly higher antibody responses to influenza/A than no vaccination or vaccination in 2021-2022 alone. Infliximab and tofacitinib are associated with lower binding antibody responses to influenza/A, similar to COVID-19 vaccine-induced antibody responses.

Immune responses and clinical outcomes after COVID-19 vaccination in patients with liver disease and liver transplant recipients

Comparative assessments of immunogenicity following different COVID-19 vaccines in patients with distinct liver diseases are lacking. SARS-CoV-2-specific T-cell and antibody responses were evaluated longitudinally after one to three vaccine doses, with long-term follow-up for COVID-19-related clinical outcomes. A total of 849 participants (355 with cirrhosis, 74 with autoimmune hepatitis [AIH], 36 with vascular liver disease [VLD], 257 liver transplant recipients [LTRs] and 127 healthy controls [HCs]) were recruited from four countries. Standardised immune assays were performed pre and post three vaccine doses (V1-3). In the total cohort, there were incremental increases in antibody titres after each vaccine dose (p <0.0001). Factors associated with reduced antibody responses were age and LT, whereas heterologous vaccination, prior COVID-19 and mRNA platforms were associated with greater responses. Although antibody titres decreased between post-V2 and pre-V3 (p= 0.012), patients with AIH, VLD, and cirrhosis had equivalent antibody responses to HCs post-V3. LTRs had lower and more heterogenous antibody titres than other groups, including post-V3 where 9% had no detectable antibodies; this was heavily influenced by intensity of immunosuppression. Vaccination increased T-cell IFNγ responses in all groups except LTRs. Patients with liver disease had lower functional antibody responses against nine Omicron subvariants and reduced T-cell responses to Omicron BA.1-specific peptides compared to wild-type. 122 cases of breakthrough COVID-19 were reported of which 5/122 (4%) were severe. Of the severe cases, 4/5 (80%) occurred in LTRs and 2/5 (40%) had no serological response post-V2. After three COVID-19 vaccines, patients with liver disease generally develop robust antibody and T-cell responses to vaccination and have mild COVID-19. However, LTRs have sustained no/low antibody titres and appear most vulnerable to severe disease. Standardised assessments of the immune response to different COVID-19 vaccines in patients with liver disease are lacking. We performed antibody and T-cell assays at multiple timepoints following up to three vaccine doses in a large cohort of patients with a range of liver conditions. Overall, the three most widely available vaccine platforms were immunogenic and appeared to protect against severe breakthrough COVID-19. This will provide reassurance to patients with chronic liver disease who were deemed at high risk of severe COVID-19 during the pre-vaccination era, however, liver transplant recipients had the lowest antibody titres and remained vulnerable to severe breakthrough infection. We also characterise the immune response to multiple SARS-CoV-2 variants and describe the interaction between disease type, severity, and vaccine platform. These insights may prove useful in the event of future viral infections which also require rapid vaccine development and delivery to patients with liver disease.

Association of vaccine-specific regulatory T cells with reduced antibody response to repeated influenza vaccination.

Repeated annual influenza vaccinations have been associated with reduced vaccine-induced antibody responses. This prospective study aimed to explore the role of vaccine antigen-specific regulatory T (Treg) cells in antibody response to repeated annual influenza vaccination. We analyzed pre- and postvaccination hemagglutination inhibition (HI) titers, seroconversion rates, seroprotection rates, vaccine antigen hemagglutinin (HA)-specific Treg cells, and conventional T (Tconv) cells. We compared these parameters between vaccinees with or without vaccine-induced seroconversion. Our multivariate logistic regression revealed that prior vaccination was significantly associated with a decreased likelihood of achieving seroconversion for both H1N1(adjusted OR, 0.03; 95% CI, 0.01-0.13) and H3N2 (adjusted OR, 0.09; 95% CI, 0.03-0.30). Furthermore, individuals who received repeated vaccinations had significantly higher levels of pre-existing HA-specific Treg cells than those who did not. We also found that vaccine-induced fold-increases in HI titers and seroconversion were negatively correlated with pre-existing HA-specific Treg cells and positively correlated with the ratio of Tconv to Treg cells. Overall, our findings suggest that repeated annual influenza vaccination is associated with a lower vaccine-induced antibody response and a higher frequency of vaccine-specific Treg cells. However, a lower frequency of pre-existing Treg cells correlates with a higher postvaccination antibody response.

Tuberculosis and COVID-19 in the elderly: factors driving a higher burden of disease.

Mycobacterium tuberculosis (M.tb) and SARS-CoV-2 are both infections that can lead to severe disease in the lower lung. However, these two infections are caused by very different pathogens (Mycobacterium vs. virus), they have different mechanisms of pathogenesis and immune response, and differ in how long the infection lasts. Despite the differences, SARS-CoV-2 and M.tb share a common feature, which is also frequently observed in other respiratory infections: the burden of disease in the elderly is greater. Here, we discuss possible reasons for the higher burden in older adults, including the effect of co-morbidities, deterioration of the lung environment, auto-immunity, and a reduced antibody response. While the answer is likely to be multifactorial, understanding the main drivers across different infections may allow us to design broader interventions that increase the health-span of older people.

B cell Tet2 promotes maturation of the antibody response through active DNA demethylation and OGT-mediated histone glycosylation of Aicdaand Prdm1loci

Abstract Epigenetic DNA methylation regulates gene expression and, therefore, cellular functions. It typically represses gene transcription, which can be re-activated by demethylation in the absence of cell division by the recently characterized Tet1, Tet2 and Tet3 dioxygenases. Tet2, the most abundant Tet protein in B cells, not only actively demethylates DNA but also promotes Ogt recruitment to chromatin to effect Ogt-dependent histone O-GlcNAcylation. This potentiates catalytic DNA demethylation to activate gene expression. To define the role of Tet2 in B cell functions and antibody responses, we generated Aicda creTet2 fl/flmice, which specifically delete Tet2 in activated B cells. Aicda creTet2 fl/flmice showed significantly reduced antibody responses to T-dependent and T-independent antigens, due to downregulation of AID and Blimp-1 expression, CSR/SHM and plasma cell differentiation. Accordingly, activated Aicda creTet2 fl/flB cells reduced DNA hydroxymethylation (resulting in increased methylation) and histone O-GlcNAcylation of Aicda and Prdm1 promoters and enhancers, thereby dampening CSR/SHM and plasma cell differentiation. These were partially rescued by enforced expression of Tet2 mutants defective in catalytic activity or Ogt-binding, but not by a double mutant lacking both activities. Accordingly, Tet2 and Ogt inhibitors synergistically inhibited Aicda and Prdm1 expression in both human and mouse B cells. Conversely, Tet2 activation by vitamin C enhanced CSR and plasma cell differentiation. Thus, Tet2 plays a B cell-intrinsic role in modulation of CSR/SHM and plasma cell differentiation through catalytic active DNA demethylation and (non-catalytic) Ogt-mediated histone O-GlcNAcylation. Supported by NIH grants AI 079705, AI 105813/105813S1, AI138944, AI 167416 and Lupus Research Alliance grant LRA 641363 to PC.

Celastrol suppresses humoral immune responses and autoimmunity by targeting the COMMD3/8 complex.

Celastrol, a bioactive molecule extracted from the Tripterygium wilfordii plant, has been shown to exhibit anti-inflammatory properties. However, its mechanism of action has not been fully elucidated. Here, we show that celastrol suppresses humoral immune responses and autoimmunity by disabling a protein complex consisting of copper metabolism MURR1 domain-containing (COMMD) 3 and COMMD8 (COMMD3/8 complex), a signaling adaptor for chemoattractant receptors. Having demonstrated the involvement of the COMMD3/8 complex in a mouse model of rheumatoid arthritis, we identified celastrol as a compound that covalently bound to and dissociated the COMMD3/8 complex. Celastrol inhibited B cell migration, reduced antibody responses, and blocked arthritis progression, recapitulating deficiency of the COMMD3/8 complex. These effects of celastrol were abolished in mice expressing a celastrol-resistant mutant of the COMMD3/8 complex. These findings establish that celastrol exerts immunosuppressive activity by targeting the COMMD3/8 complex. Our study suggests that the COMMD3/8 complex is a potentially druggable target in autoimmune diseases and points to celastrol as a lead pharmacologic candidate in this capacity.