Self-Adjuvanting Lipoprotein Conjugate αGalCer-RBD Induces Potent Immunity against SARS-CoV-2 and its Variants of Concern.

Safe and effective vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants are the best approach to successfully combat the COVID-19 pandemic. The receptor-binding domain (RBD) of the viral spike protein is a major target to develop candidate vaccines. α-Galactosylceramide (αGalCer), a potent invariant natural killer T cell (iNKT) agonist, was site-specifically conjugated to the N-terminus of the RBD to form an adjuvant-protein conjugate, which was anchored on the liposome surface. This is the first time that an iNKT cell agonist was conjugated to the protein antigen. Compared to the unconjugated RBD/αGalCer mixture, the αGalCer-RBD conjugate induced significantly stronger humoral and cellular responses. The conjugate vaccine also showed effective cross-neutralization to all variants of concern (B.1.1.7/alpha, B.1.351/beta, P.1/gamma, B.1.617.2/delta, and B.1.1.529/omicron). These results suggest that the self-adjuvanting αGalCer-RBD has great potential to be an effective COVID-19 vaccine candidate, and this strategy might be useful for designing various subunit vaccines.

Impaired humoral and cellular response to primary COVID-19 vaccination in patients less than 2 years after allogeneic bone marrow transplant.

Allogeneic haematopoietic stem cell transplant (HSCT) recipients remain at high risk of adverse outcomes from coronavirus disease 2019 (COVID-19) and emerging variants. The optimal prophylactic vaccine strategy for this cohort is not defined. T cell-mediated immunity is a critical component of graft-versus-tumour effect and in determining vaccine immunogenicity. Using validated anti-spike (S) immunoglobulin G (IgG) and S-specific interferon-gamma enzyme-linked immunospot (IFNγ-ELIspot) assays we analysed response to a two-dose vaccination schedule (either BNT162b2 or ChAdOx1) in 33 HSCT recipients at ≤2 years from transplant, alongside vaccine-matched healthy controls (HCs). After two vaccines, infection-naïve HSCT recipients had a significantly lower rate of seroconversion compared to infection-naïve HCs (25/32 HSCT vs. 39/39 HCs no responders) and had lower S-specific T-cell responses. The HSCT recipients who received BNT162b2 had a higher rate of seroconversion compared to ChAdOx1 (89% vs. 74%) and significantly higher anti-S IgG titres (p = 0.022). S-specific T-cell responses were seen after one vaccine in HCs and HSCT recipients. However, two vaccines enhanced S-specific T-cell responses in HCs but not in the majority of HSCT recipients. These data demonstrate limited immunogenicity of two-dose vaccination strategies in HSCT recipients, bolstering evidence of the need for additional boosters and/or alternative prophylactic measures in this group.

First-dose mRNA vaccination is sufficient to reactivate immunological memory to SARS-CoV-2 in subjects who have recovered from COVID-19.

The characterization of the adaptive immune response to COVID-19 vaccination in individuals who recovered from SARS-CoV-2 infection may define current and future clinical practice. To determine the effect of the 2-dose BNT162b2 mRNA COVID-19 vaccination schedule in individuals who recovered from COVID-19 (COVID-19-recovered subjects) compared with naive subjects, we evaluated SARS-CoV-2 Spike-specific T and B cell responses, as well as specific IgA, IgG, IgM, and neutralizing antibodies titers in 22 individuals who received the BNT162b2 mRNA COVID-19 vaccine, 11 of whom had a previous history of SARS-CoV-2 infection. Evaluations were performed before vaccination and then weekly until 7 days after second injection. Data obtained clearly showed that one vaccine dose is sufficient to increase both cellular and humoral immune response in COVID-19-recovered subjects without any additional improvement after the second dose. On the contrary, the second dose proved mandatory in naive subjects to further enhance the immune response. These findings were further confirmed at the serological level in a larger cohort of naive (n = 68) and COVID-19-recovered (n = 29) subjects, tested up to 50 days after vaccination. These results question whether a second vaccine injection in COVID-19-recovered subjects is required, and indicate that millions of vaccine doses may be redirected to naive individuals, thus shortening the time to reach herd immunity.

Self-Assembled Particles Combining SARS-CoV-2 RBD Protein and RBD DNA Vaccine Induce Synergistic Enhancement of the Humoral Response in Mice.

Despite the fact that a range of vaccines against COVID-19 have already been created and are used for mass vaccination, the development of effective, safe, technological, and affordable vaccines continues. We have designed a vaccine that combines the recombinant protein and DNA vaccine approaches in a self-assembled particle. The receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 was conjugated to polyglucin:spermidine and mixed with DNA vaccine (pVAXrbd), which led to the formation of particles of combined coronavirus vaccine (CCV-RBD) that contain the DNA vaccine inside and RBD protein on the surface. CCV-RBD particles were characterized with gel filtration, electron microscopy, and biolayer interferometry. To investigate the immunogenicity of the combined vaccine and its components, mice were immunized with the DNA vaccine pVAXrbd or RBD protein as well as CCV-RBD particles. The highest antigen-specific IgG and neutralizing activity were induced by CCV-RBD, and the level of antibodies induced by DNA or RBD alone was significantly lower. The cellular immune response was detected only in the case of DNA or CCV-RBD vaccination. These results demonstrate that a combination of DNA vaccine and RBD protein in one construct synergistically increases the humoral response to RBD protein in mice.

Case Report: Clinical Management of a Patient With Metastatic Non-Small Cell Lung Cancer Newly Receiving Immune Checkpoint Inhibition During Symptomatic COVID-19.

Effects of initiation of programmed-death-protein 1 (PD1) blockade during active SARS-CoV-2 infection on antiviral immunity, COVID-19 course, and underlying malignancy are unclear. We report on the management of a male in his early 40s presenting with highly symptomatic metastatic lung cancer and active COVID-19 pneumonia. After treatment initiation with pembrolizumab, carboplatin, and pemetrexed, the respiratory situation initially worsened and high-dose corticosteroids were initiated due to suspected pneumonitis. After improvement and SARS-CoV-2 clearance, anti-cancer treatment was resumed without pembrolizumab. Immunological analyses with comparison to otherwise healthy SARS-CoV-2-infected ambulatory patients revealed a strong humoral immune response with higher levels of SARS-CoV-2-reactive IgG and neutralizing serum activity. Additionally, sustained increase of Tfh as well as activated CD4+ and CD8+ T cells was observed. Sequential CT scans showed regression of tumor lesions and marked improvement of the pulmonary situation, with no signs of pneumonitis after pembrolizumab re-challenge as maintenance. At the latest follow-up, the patient is ambulatory and in ongoing partial remission on pembrolizumab. In conclusion, anti-PD1 initiation during active COVID-19 pneumonia was feasible and cellular and humoral immune responses to SARS-CoV-2 appeared enhanced in our hospitalized patient. However, distinguishing COVID-19-associated changes from anti-PD1-associated immune-related pneumonitis posed a considerable clinical, radiographic, and immunologic challenge.

Analysis of the humoral and cellular immune response after a full course of BNT162b2 anti-SARS-CoV-2 vaccine in cancer patients treated with PD-1/PD-L1 inhibitors with or without chemotherapy: an update after 6 months of follow-up.

BACKGROUND: The durability of immunogenicity of SARS-CoV-2 vaccination in cancer patients remains to be elucidated. We prospectively evaluated the immunogenicity of the vaccine in triggering both the humoral and the cell-mediated immune response in cancer patients treated with anti-programmed cell death protein 1/programmed death-ligand 1 with or without chemotherapy 6 months after BNT162b2 vaccine. PATIENTS AND METHODS: In the previous study, 88 patients were enrolled, whereas the analyses below refer to the 60 patients still on immunotherapy at the time of the follow-up. According to previous SARS-CoV-2 exposure, patients were classified as SARS-CoV-2-naive (without previous SARS-CoV-2 exposure) and SARS-CoV-2-experienced (with previous SARS-CoV-2 infection). Neutralizing antibody (NT Ab) titer against the B.1.1 strain and total anti-spike immunoglobulin G concentration were quantified in serum samples. The enzyme-linked immunosorbent spot assay was used for quantification of anti-spike interferon-γ (IFN-γ)-producing cells/106 peripheral blood mononuclear cells. Fifty patients (83.0%) were on immunotherapy alone, whereas 10 patients (7%) were on chemo-immunotherapy. We analyzed separately patients on immunotherapy and patients on chemo-immunotherapy. RESULTS: The median T-cell response at 6 months was significantly lower than that measured at 3 weeks after vaccination [50 interquartile range (IQR) 20-118.8 versus 175 IQR 67.5-371.3 IFN-γ-producing cells/106 peripheral blood mononuclear cells; P < 0.0001]. The median reduction of immunoglobulin G concentration was 88% in SARS-CoV-2-naive subjects and 2.1% in SARS-CoV-2-experienced subjects. SARS-CoV-2 NT Ab titer was maintained in SARS-CoV-2-experienced subjects, whereas a significant decrease was observed in SARS-CoV-2-naive subjects (from median 1 : 160, IQR 1 : 40-1 : 640 to median 1 : 20, IQR 1 : 10-1 : 40; P < 0.0001). A weak correlation was observed between SARS-CoV-2 NT Ab titer and spike-specific IFN-γ-producing cells at both 6 months and 3 weeks after vaccination (r = 0.467; P = 0.0002 and r = 0.428; P = 0.0006, respectively). CONCLUSIONS: Our work highlights a reduction in the immune response in cancer patients, particularly in SARS-CoV-2-naive subjects. Our data support administering a third dose of COVID-19 vaccine to cancer patients treated with programmed cell death protein 1/programmed death-ligand 1 inhibitors.

Potential Association Between Dietary Fibre and Humoral Response to the Seasonal Influenza Vaccine.

Influenza vaccination is an effective public health measure to reduce the risk of influenza illness, particularly when the vaccine is well matched to circulating strains. Notwithstanding, the efficacy of influenza vaccination varies greatly among vaccinees due to largely unknown immunological determinants, thereby dampening population-wide protection. Here, we report that dietary fibre may play a significant role in humoral vaccine responses. We found dietary fibre intake and the abundance of fibre-fermenting intestinal bacteria to be positively correlated with humoral influenza vaccine-specific immune responses in human vaccinees, albeit without reaching statistical significance. Importantly, this correlation was largely driven by first-time vaccinees; prior influenza vaccination negatively correlated with vaccine immunogenicity. In support of these observations, dietary fibre consumption significantly enhanced humoral influenza vaccine responses in mice, where the effect was mechanistically linked to short-chain fatty acids, the bacterial fermentation product of dietary fibre. Overall, these findings may bear significant importance for emerging infectious agents, such as COVID-19, and associated de novo vaccinations.

Importance of the second SARS-CoV-2 vaccination dose for achieving serological response in patients with rheumatoid arthritis and seronegative spondyloarthritis.

OBJECTIVES: To assess the kinetics of humoral response after the first and second dose of messenger RNA (mRNA) vaccines in patients with inflammatory joint diseases compared with healthy controls (HC). To analyse factors influencing the quantity of the immune response. METHODS: We enrolled patients with rheumatoid arthritis (RA) and seronegative spondyloarthritis (SpA), excluding those receiving B-cell depleting therapies and assessed the humoral response to mRNA vaccines after the first and the second dose of the vaccine in terms of seroconversion rate and titre. We compared the results to a HC group and analysed the influence of therapies as well as other characteristics on the humoral response. RESULTS: Samples from 53 patients with RA, 46 patients with SpA and 169 healthy participants were analysed. Seroconversion rates after the first immunisation were only 54% in patients with inflammatory arthritis compared with 98% in the HC group. However, seroconversion rates were 100% in all groups after second immunisation. Patients developed reduced antibody titres after the first vaccination compared with HC, but there was no difference after the second dose. While disease modifying anti-rheumatic drug (DMARD) monotherapy did not affect antibody levels, seroconversion rates as well as titre levels were reduced in patients receiving a combination of DMARDs compared with HC. CONCLUSIONS: Patients with inflammatory joint diseases under DMARD therapy show impaired humoral responses to the first vaccine dose but excellent final responses to vaccination with mRNA vaccines. Therefore, the full course of two immunisations is necessary for efficient vaccination responses in patients with inflammatory arthritis under DMARD therapy.

Antineoplastic treatment class modulates COVID-19 mRNA-BNT162b2 vaccine immunogenicity in cancer patients: a secondary analysis of the prospective Vax-On study.

BACKGROUND: Preliminary analysis from the Vax-On study did not find a correlation between cancer treatment type and antibody response to COVID-19 vaccination. We carried out a secondary subgroup analysis to verify the effects of comprehensive cancer treatment classification on vaccine immunogenicity. METHODS: The Vax-On study prospectively enrolled patients who started a two-dose messenger RNA-BNT162b2 vaccine schedule from 9 March 2021 to 12 April 2021 (timepoint-1). Those on active treatment within the previous 28 days accounted for the exposed cases. Patients who had discontinued such treatment by at least 28 days or received intravesical therapy represented the control cases. Quantification of immunoglobulin G (IgG) antibodies against the receptor binding domain of the S1 subunit of the SARS-CoV-2 spike protein was carried out before the second dose (timepoint-2) and 8 weeks thereafter (timepoint-3). Seroconversion response was defined at ≥50 arbitrary units/ml IgG titer. Classification of antineoplastic agents was based on their pharmacodynamic properties. RESULTS: Three hundred and sixty-six patients were enrolled (86 and 260 as control and exposed cases, respectively). Univariate analysis revealed a significantly lower IgG titer after both doses of vaccine in subgroups treated with tyrosine kinase inhibitors (TKIs), multiple cytotoxic agents, alkylating agents, and topoisomerase inhibitors. At timepoint-3, seroconversion response was significantly impaired in the topoisomerase inhibitors and mechanistic target of rapamycin (mTOR) inhibitors subgroups. After multivariate testing, treatment with alkylating agents and TKIs was significantly associated with a reduced change in IgG titer at timepoint-2. Treatment with mTOR inhibitors resulted in a similar interaction at each timepoint. Cyclin-dependent kinase 4/6 inhibitor treatment was independently correlated with an incremental variation in IgG titer at timepoint-3. Specific subgroups (TKIs, antimetabolites, alkylating agents, and multiple-agent chemotherapy) predicted lack of seroconversion at timepoint-2, but their effect was not retained at timepoint-3. Eastern Cooperative Oncology Group performance status 2, immunosuppressive corticosteroid dosing, and granulocyte colony-stimulating factor use were independently linked to lower IgG titer after either dose of vaccine. CONCLUSIONS: Drugs interfering with DNA synthesis, multiple-agent cytotoxic chemotherapy, TKIs, mTOR and cyclin-dependent kinase 4/6 inhibitors differentially modulate humoral response to messenger RNA-BNT162b2 vaccine.

Cellular and humoral immune responses following SARS-CoV-2 mRNA vaccination in patients with multiple sclerosis on anti-CD20 therapy.

SARS-CoV-2 messenger RNA vaccination in healthy individuals generates immune protection against COVID-19. However, little is known about SARS-CoV-2 mRNA vaccine-induced responses in immunosuppressed patients. We investigated induction of antigen-specific antibody, B cell and T cell responses longitudinally in patients with multiple sclerosis (MS) on anti-CD20 antibody monotherapy (n = 20) compared with healthy controls (n = 10) after BNT162b2 or mRNA-1273 mRNA vaccination. Treatment with anti-CD20 monoclonal antibody (aCD20) significantly reduced spike-specific and receptor-binding domain (RBD)-specific antibody and memory B cell responses in most patients, an effect ameliorated with longer duration from last aCD20 treatment and extent of B cell reconstitution. By contrast, all patients with MS treated with aCD20 generated antigen-specific CD4 and CD8 T cell responses after vaccination. Treatment with aCD20 skewed responses, compromising circulating follicular helper T (TFH) cell responses and augmenting CD8 T cell induction, while preserving type 1 helper T (TH1) cell priming. Patients with MS treated with aCD20 lacking anti-RBD IgG had the most severe defect in circulating TFH responses and more robust CD8 T cell responses. These data define the nature of the SARS-CoV-2 vaccine-induced immune landscape in aCD20-treated patients and provide insights into coordinated mRNA vaccine-induced immune responses in humans. Our findings have implications for clinical decision-making and public health policy for immunosuppressed patients including those treated with aCD20.

Delivery of STING agonists for adjuvanting subunit vaccines.

Adjuvant is an essential component in subunit vaccines. Many agonists of pathogen recognition receptors have been developed as potent adjuvants to optimize the immunogenicity and efficacy of vaccines. Recently discovered cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway has attracted much attention as it is a key mediator for modulating immune responses. Vaccines adjuvanted with STING agonists are found to mediate a robust immune defense against infections and cancer. In this review, we first discuss the mechanisms of STING agonists in the context of vaccination. Next, we present recent progress in novel STING agonist discovery and the delivery strategies. We next highlight recent work in optimizing the efficacy while minimizing toxicity of STING agonist-assisted subunit vaccines for protection against infectious diseases or treatment of cancer. Finally, we share our perspectives of current issues and future directions in further developing STING agonists for adjuvanting subunit vaccines.

Humoral Response of Renal Transplant Recipients to the BNT162b2 SARS-CoV-2 mRNA Vaccine Using Both RBD IgG and Neutralizing Antibodies.

BACKGROUND: Data about SARS-CoV-2 vaccines efficacy in renal transplant recipients (RTR) are lacking. METHODS: To reveal predictors for humoral response to BNT162b2 vaccine among RTR, patients were divided into positive (N = 42) and negative (N = 78) response groups based on receptor-binding domain (RBD) immunoglobulin G (IgG) ≥1.1 and neutralizing antibodies (NA) ≥16 dilution versus RBD IgG <1.1 or NA <16, respectively. NA were detected using a SARS-CoV-2 pseudo-virus. RESULTS: NA were detected in only 42 of 120 (35%) of RTR versus 197 of 202 (97.5%) immunocompetent controls (P < 0.001). NA geometric mean titers in RTR were significantly lower versus the control group {83.7 (95% confidence interval [CI], 50.5-138.8) versus 482 (95% CI, 411-566), P < 0.001}. In a multivariable analysis, mycophenolic acid (MPA) dose and hemoglobin level were found to be independent predictors for antibody response in RTR. A positive response rate of 27% versus 63% was observed in patients on and off MPA, respectively. An increase in MPA dose by 1 mg/kg weight reduced the odds for a positive response by 17% (odds ratio = 0.83; 95% CI, 0.75-0.92; P < 0.001). Geometric mean titers for RBD IgG were significantly reduced as MPA daily dose increased. Hemoglobin blood level <13 g/dL reduced the antibody response by 63% (P = 0.04). Pain at the injection site after the second vaccine dose was significantly higher in the responders versus nonresponders (20.5% versus 5.5%, P = 0.01). CONCLUSIONS: Only 35% of RTR develop NA to the BNT162b2 mRNA vaccine. MPA is a major suppressor of antibody response in RTR.

COVID19 Disease Map, a computational knowledge repository of virus-host interaction mechanisms.

We need to effectively combine the knowledge from surging literature with complex datasets to propose mechanistic models of SARS-CoV-2 infection, improving data interpretation and predicting key targets of intervention. Here, we describe a large-scale community effort to build an open access, interoperable and computable repository of COVID-19 molecular mechanisms. The COVID-19 Disease Map (C19DMap) is a graphical, interactive representation of disease-relevant molecular mechanisms linking many knowledge sources. Notably, it is a computational resource for graph-based analyses and disease modelling. To this end, we established a framework of tools, platforms and guidelines necessary for a multifaceted community of biocurators, domain experts, bioinformaticians and computational biologists. The diagrams of the C19DMap, curated from the literature, are integrated with relevant interaction and text mining databases. We demonstrate the application of network analysis and modelling approaches by concrete examples to highlight new testable hypotheses. This framework helps to find signatures of SARS-CoV-2 predisposition, treatment response or prioritisation of drug candidates. Such an approach may help deal with new waves of COVID-19 or similar pandemics in the long-term perspective.

Airway antibodies emerge according to COVID-19 severity and wane rapidly but reappear after SARS-CoV-2 vaccination.

Understanding the presence and durability of antibodies against SARS-CoV-2 in the airways is required to provide insights into the ability of individuals to neutralize the virus locally and prevent viral spread. Here, we longitudinally assessed both systemic and airway immune responses upon SARS-CoV-2 infection in a clinically well-characterized cohort of 147 infected individuals representing the full spectrum of COVID-19 severity, from asymptomatic infection to fatal disease. In addition, we evaluated how SARS-CoV-2 vaccination influenced the antibody responses in a subset of these individuals during convalescence as compared with naive individuals. Not only systemic but also airway antibody responses correlated with the degree of COVID-19 disease severity. However, although systemic IgG levels were durable for up to 8 months, airway IgG and IgA declined significantly within 3 months. After vaccination, there was an increase in both systemic and airway antibodies, in particular IgG, often exceeding the levels found during acute disease. In contrast, naive individuals showed low airway antibodies after vaccination. In the former COVID-19 patients, airway antibody levels were significantly elevated after the boost vaccination, highlighting the importance of prime and boost vaccinations for previously infected individuals to obtain optimal mucosal protection.

BNT162b2 vaccine-induced humoral and cellular responses against SARS-CoV-2 variants in systemic lupus erythematosus.

OBJECTIVES: Our aim was to evaluate systemic lupus erythematosus (SLE) disease activity and SARS-CoV-2-specific immune responses after BNT162b2 vaccination. METHODS: In this prospective study, disease activity and clinical assessments were recorded from the first dose of vaccine until day 15 after the second dose in 126 patients with SLE. SARS-CoV-2 antibody responses were measured against wild-type spike antigen, while serum-neutralising activity was assessed against the SARS-CoV-2 historical strain and variants of concerns (VOCs). Vaccine-specific T cell responses were quantified by interferon-γ release assay after the second dose. RESULTS: BNT162b2 was well tolerated and no statistically significant variations of BILAG (British Isles Lupus Assessment Group) and SLEDAI (SLE Disease Activity Index) scores were observed throughout the study in patients with SLE with active and inactive disease at baseline. Mycophenolate mofetil (MMF) and methotrexate (MTX) treatments were associated with drastically reduced BNT162b2 antibody response (ß=-78, p=0.007; ß=-122, p<0.001, respectively). Anti-spike antibody response was positively associated with baseline total immunoglobulin G serum levels, naïve B cell frequencies (ß=2, p=0.018; ß=2.5, p=0.003) and SARS-CoV-2-specific T cell response (r=0.462, p=0.003). In responders, serum neutralisation activity decreased against VOCs bearing the E484K mutation but remained detectable in a majority of patients. CONCLUSION: MMF, MTX and poor baseline humoral immune status, particularly low naïve B cell frequencies, are independently associated with impaired BNT162b2 mRNA antibody response, delineating patients with SLE who might need adapted vaccine regimens and follow-up.

Immune responses to two and three doses of the BNT162b2 mRNA vaccine in adults with solid tumors.

Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have shown high efficacy, but immunocompromised participants were excluded from controlled clinical trials. In this study, we compared immune responses to the BNT162b2 mRNA Coronavirus Disease 2019 vaccine in patients with solid tumors (n = 53) who were on active cytotoxic anti-cancer therapy to a control cohort of participants without cancer (n = 50). Neutralizing antibodies were detected in 67% of patients with cancer after the first immunization, followed by a threefold increase in median titers after the second dose. Similar patterns were observed for spike protein-specific serum antibodies and T cells, but the magnitude of each of these responses was diminished relative to the control cohort. In most patients with cancer, we detected spike receptor-binding domain and other S1-specific memory B cell subsets as potential predictors of anamnestic responses to additional immunizations. We therefore initiated a phase 1 trial for 20 cancer cohort participants of a third vaccine dose of BNT162b2 ( NCT04936997 ); primary outcomes were immune responses, with a secondary outcome of safety. At 1 week after a third immunization, 16 participants demonstrated a median threefold increase in neutralizing antibody responses, but no improvement was observed in T cell responses. Adverse events were mild. These results suggest that a third dose of BNT162b2 is safe, improves humoral immunity against SARS-CoV-2 and could be immunologically beneficial for patients with cancer on active chemotherapy.