Antibody and T cell responses to Sinopharm/BBIBP-CorV in naive and previously infected individuals in Sri Lanka

Background: As there are limited data of the immunogenicity of the Sinopharm/BBIBP-CorV in different populations, antibody responses against different SARS-CoV-2 variants of concern and T cell responses, we investigated the immunogenicity of the vaccine, in individuals in Sri Lanka. Methods: SARS-CoV-2-specific antibodies were measured in 282 individuals who were seronegative at baseline, and ACE2 receptor blocking antibodies, antibodies to the receptor binding domain (RBD) of the wild type (WT), B.1.1.7, B.1.351 and B.1.617.2, ex vivo and cultured IFNγ ELISpot assays, intracellular cytokine secretion assays and B cell ELISpot assays were carried out in a sub cohort of the vaccinees at 4 weeks and at 6 weeks (2 weeks after the second dose). Results: 95% of the vaccinees seroconverted, although the seroconversion rates were significantly lower (p<0.001) in individuals >60 years (93.3%) compared to those who were 20 to 39 years (98.9%). 81.25% had ACE2 receptor blocking antibodies at 6 weeks, and there was no difference in these antibody titres in vaccine sera compared to convalescent sera (p=0.44). Vaccinees had significantly less (p<0.0001) antibodies to the RBD of WT and B.1.1.7, although there was no difference in antibodies to the RBD of B.1.351 and B.1.617.2 compared to convalescent sera. 27.7% of 46.4% of vaccinees had ex vivo IFNγ and cultured ELISpot responses respectively, and IFNγ and CD107a responses were detected by flow cytometry. Conclusions: Sinopharm/BBIBP-CorV appeared to induce high seroconversion rates and induce a similar level of antibody responses against ACE2 receptor, B.1.617.2 and B.1.351 as seen following natural infection.

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Kinetics of immune responses to the AZD1222/Covishield vaccine with varying dose intervals in Sri Lankan individuals

10.1101/2021.10.27.21265561 ◽

2021 ◽

Author(s):

Chandima Jeewandara ◽

Inoka Sepali Aberathna ◽

Laksiri Gomes ◽

Pradeep Darshana Pushpakumara ◽

Saubhagya Danasekara ◽

...

Keyword(s):

T Cell ◽

Immune Responses ◽

Positive Response ◽

Ex Vivo ◽

Age Groups ◽

T Cell Responses ◽

Cell Responses ◽

Antibody Titres ◽

Blocking Antibodies ◽

Kinetics Of

AbstractBackgroundTo understand the kinetics of immune responses with different dosing gaps of the AZD1222 vaccine, we compared antibody and T cell responses in two cohorts with two different dosing gaps.MethodsAntibodies to the SARS-CoV-2 virus were assessed in 297 individuals with a dosing gap of 12 weeks, sampled at 12 weeks post second dose (cohort 1) and in 77 individuals with a median dosing gap of 21.4 weeks (cohort 2) sampled 6 weeks post second dose. ACE2 receptor blocking antibodies (ACE2R-Abs), antibodies to the receptor binding domain (RBD) of the virus and variants of concern (VOC) and ex vivo T cell responses were assessed in a sub cohort.ResultsAll individuals (100%) had SARS-CoV-2 specific total antibodies and 94.2% of cohort 1 and 97.1% of cohort 2 had ACE2R-blocking Abs. There was no difference in antibody titres or positivity rates in different age groups in both cohorts. The ACE2R-blocking Abs (p<0.0001) and antibodies to the RBD of the VOCs were significantly higher in cohort 2, compared to cohort 1. 41.2% to 65.8% of different age groups gave a positive response by the haemagglutination assay to the RBD of the ancestral virus and VOCs in cohort 1, while 53.6% to 90% gave a positive response in cohort 2. 17/57 (29.8%) of cohort 1 and 17/29 (58.6%) of cohort 2 had ex vivo IFNγ ELISpot responses above the positive threshold. The ACE2R-blocking antibodies and ex vivo IFNγ ELISpot responses at 12 weeks post-first dose, significantly correlated with levels 12 weeks post second dose (Spearman’s r=0.46, p=0.008) and (Spearman’s r=0.71, p<0.0001) respectively.ConclusionsBoth dosing schedules resulted in high levels of antibody and T cell responses post vaccination, although those with a longer dosing gap had a higher magnitude of responses, possibly as immune responses were measured 6 weeks post second dose compared to 12 weeks post second dose.

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Immune responses to a single dose of the AZD1222/Covishield vaccine at 16 weeks in individuals in Sri Lanka

10.1101/2021.07.26.21261122 ◽

2021 ◽

Author(s):

Chandima Jeewandara ◽

Dinuka Guruge ◽

Pradeep Pushpakumara ◽

Achala Kamaladasa ◽

Inoka Aberathna ◽

...

Keyword(s):

Single Dose ◽

T Cell ◽

B Cell ◽

High Frequency ◽

Ex Vivo ◽

P Value ◽

Receptor Blocking ◽

Specific Antibodies ◽

Cell Responses ◽

Blocking Antibodies

Introduction: Due to limited access to vaccines, many countries have only administered a single dose of the AZD1222, while the dosage intervals have increased ≥ weeks. We sought to investigate the immunogenicity of a single dose of vaccine at ≥ 16 weeks. Methods: SARS-CoV-2 specific antibodies in 553 individuals and antibodies to the receptor binding domain (RBD) of the Wuhan virus (WT) and the variants of concern (VOCs), ACE2 receptor blocking antibodies, ex vivo and cultured IFNγ T cell responses and B cell ELISpot responses were investigated in a sub-cohort. Results: The seropositivity rates in those >70 years of age (93.7%) was not significantly different compared to other age groups (97.7 to 98.2, Pearson Chi-Square = 7.8, p-value = 0.05). The antibody titres (antibody index) significantly declined (p<0.0001) with increase in age. 18/69 (26.1%) of individuals did not have ACE2 receptor blocking antibodies, while responses to the RBD of WT (p=0.03), B.1.1.7 (p=0.04) and B.1.617.2 (p=0.02) were significantly lower in those who were >60 years. Ex vivo IFN γ T cell ELISpot responses were seen in 10/66 (15.1%), while only a few expressed CD107a. However, >85% had a high frequency of cultured IFNγ T cell ELISpot responses and B cell ELISpots. Conclusion: Virus specific antibodies were maintained at ≥ 16 weeks after receiving a single dose of AZD1222, although levels were lower to VOCs, especially in older individuals. A single dose induced a high frequency of memory T and B cell responses.

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Novel Mumps Virus Epitopes Reveal Robust Cytotoxic T Cell Responses After Natural Infection but Not After Vaccination

10.21203/rs.3.rs-147373/v1 ◽

2021 ◽

Author(s):

Patricia Kaaijk ◽

Maarten Emmelot ◽

Hugo Meiring ◽

Cecile van Els ◽

Jelle de Wit

Keyword(s):

T Cells ◽

T Cell ◽

Ex Vivo ◽

Natural Infection ◽

T Cell Responses ◽

Mumps Virus ◽

Cytotoxic T Cell ◽

Cell Responses ◽

Cell Immunity ◽

Hla Class I Molecules

Abstract Mumps is nowadays re-emerging despite vaccination. The contribution of T cell immunity to protection against mumps has not been clearly defined. Previously, we described a set of 41 peptides that were eluted from human leukocyte antigen (HLA) class I molecules of mumps virus (MuV)-infected cells. Here, we confirmed immunogenicity of five novel HLA-B*07:02- and HLA-A*01:01-restricted MuV T cell epitopes from this set of peptides. High frequencies of T cells against these five MuV epitopes could be detected ex vivo in all tested mumps patients. Moreover, these epitope-specific T cells derived from mumps patients displayed strong cytotoxic activity. In contrast, only marginal T cell responses against these novel MuV epitopes could be detected in recently vaccinated persons, corroborating earlier findings. Identifying which MuV epitopes are dominantly targeted in the mumps-specific CD8+ T- response is an important step towards better understanding in the discrepancies between natural infection or vaccination-induced cell-mediated immune protection

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Antibody and T-cell responses to a single dose of the AZD1222/Covishield vaccine in previously SARS-CoV-2 infected and naive health care workers in Sri Lanka

10.1101/2021.04.09.21255194 ◽

2021 ◽

Author(s):

Chandima Jeewandara ◽

Achala Kamaladasa ◽

Pradeep D Pushpakumara ◽

Deshni Jayathilaka ◽

Inoka Sepali ◽

...

Keyword(s):

Health Care ◽

Single Dose ◽

T Cell ◽

Health Care Workers ◽

Ex Vivo ◽

T Cell Responses ◽

Wild Type Virus ◽

Cell Responses ◽

Care Workers ◽

Blocking Antibodies

Background: In order to determine the immunogenicity of a single dose of the AZD1222/Covishield vaccine in a real-world situation, we assessed the immunogenicity, in a large cohort of health care workers in Sri Lanka. Methods: SARS-CoV-2 antibodies was carried out in 607 naive and 26 previously infected health care workers (HCWs) 28 to 32 days following a single dose of the vaccine. Haemagglutination test (HAT) for antibodies to the receptor binding domain (RBD) of the wild type virus, B.1.1.7, B.1.351 and the surrogate neutralization assay (sVNT) was carried out in 69 naive and 26 previously infected individuals. Spike protein (pools S1 and S2) specific T cell responses were measured by ex vivo ELISpot IFNg; assays in 76 individuals. Results: 92.9% of previously naive HCWs seroconverted to a single dose of the vaccine, irrespective of age and gender; and ACE2 blocking antibodies were detected in 67/69 (97.1%) previously naive vaccine recipients. Although high levels of antibodies were found to the RBD of the wild type virus, the titres for B.1.1.7 and B.1.351 were lower in previously naive HCWs. Ex vivo T cell responses were observed to S1 in 63.9% HCWs and S2 in 31.9%. The ACE2 blocking titres measured by the sVNT significantly increased (p<0.0001) from a median of 54.1 to 97.9 % of inhibition, in previously infected HCWs and antibodies to the RBD for the variants B.1.1.7 and B.1.351 also significantly increased. Discussion: a single dose of the AZD1222/Covishield vaccine was shown to be highly immunogenic in previously naive individuals inducing antibody levels greater than following natural infection. In infected individuals, a single dose induced very high levels of ACE2 blocking antibodies and antibodies to RBDs of SARS-CoV-2 variants of concern.

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Dengue virus infection elicits highly polarized CX3CR1+cytotoxic CD4+T cells associated with protective immunity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1505956112 ◽

2015 ◽

Vol 112 (31) ◽

pp. E4256-E4263 ◽

Cited By ~ 139

Author(s):

Daniela Weiskopf ◽

Derek J. Bangs ◽

John Sidney ◽

Ravi V. Kolla ◽

Aruna D. De Silva ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Dengue Virus ◽

Ex Vivo ◽

Natural Infection ◽

Dengue Infection ◽

Flow Cytometric Analysis ◽

T Cell Responses ◽

Severe Dengue ◽

Cell Responses

Dengue virus (DENV) is a rapidly spreading pathogen with unusual pathogenesis, and correlates of protection from severe dengue disease and vaccine efficacy have not yet been established. Although DENV-specific CD8+T-cell responses have been extensively studied, the breadth and specificity of CD4+T-cell responses remains to be defined. Here we define HLA-restricted CD4+T-cell epitopes resulting from natural infection with dengue virus in a hyperepidemic setting. Ex vivo flow-cytometric analysis of DENV-specific CD4+T cells revealed that the virus-specific cells were highly polarized, with a strong bias toward a CX3CR1+Eomesodermin+perforin+granzyme B+CD45RA+CD4 CTL phenotype. Importantly, these cells correlated with a protective HLA DR allele, and we demonstrate that these cells have direct ex vivo DENV-specific cytolytic activity. We speculate that cytotoxic dengue-specific CD4+T cells may play a role in the control of dengue infection in vivo, and this immune correlate may be a key target for dengue virus vaccine development.

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Novel mumps virus epitopes reveal robust cytotoxic T cell responses after natural infection but not after vaccination

Scientific Reports ◽

10.1038/s41598-021-92926-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Patricia Kaaijk ◽

Maarten E. Emmelot ◽

Hugo D. Meiring ◽

Cécile A. C. M. van Els ◽

Jelle de Wit

Keyword(s):

T Cells ◽

T Cell ◽

Ex Vivo ◽

Natural Infection ◽

T Cell Responses ◽

Mumps Virus ◽

Cytotoxic T Cell ◽

Cell Responses ◽

Cell Immunity ◽

Hla Class I Molecules

AbstractMumps is nowadays re-emerging despite vaccination. The contribution of T cell immunity to protection against mumps has not been clearly defined. Previously, we described a set of 41 peptides that were eluted from human leukocyte antigen (HLA) class I molecules of mumps virus (MuV)-infected cells. Here, we confirmed immunogenicity of five novel HLA-B*07:02- and HLA-A*01:01-restricted MuV T cell epitopes from this set of peptides. High frequencies of T cells against these five MuV epitopes could be detected ex vivo in all tested mumps patients. Moreover, these epitope-specific T cells derived from mumps patients displayed strong cytotoxic activity. In contrast, only marginal T cell responses against these novel MuV epitopes could be detected in recently vaccinated persons, corroborating earlier findings. Identifying which MuV epitopes are dominantly targeted in the mumps-specific CD8+ T- response is an important step towards better understanding in the discrepancies between natural infection or vaccination-induced cell-mediated immune protection.

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413 GEN-009, a personalized neoantigen vaccine, elicits robust immune responses in individuals with advanced or metastatic solid tumors

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0413 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A438-A438

Author(s):

Mara Shainheit ◽

Devin Champagne ◽

Gabriella Santone ◽

Syukri Shukor ◽

Ece Bicak ◽

...

Keyword(s):

Clinical Trial ◽

T Cells ◽

T Cell ◽

Immune Responses ◽

Solid Tumors ◽

Ex Vivo ◽

T Cell Responses ◽

Checkpoint Blockade ◽

T Cell Subsets ◽

Cell Responses

BackgroundATLASTM is a cell-based bioassay that utilizes a cancer patient‘s own monocyte-derived dendritic cells and CD4+ and CD8+ T cells to screen their mutanome and identify neoantigens that elicit robust anti-tumor T cell responses, as well as, deleterious InhibigensTM.1 GEN-009, a personalized vaccine comprised of 4–20 ATLAS-identified neoantigens combined with Hiltonol®, harnesses the power of neoantigen-specific T cells to treat individuals with solid tumors. The safety and efficacy of GEN-009 is being assessed in a phase 1/2a clinical trial (NCT03633110).MethodsA cohort of 15 adults with solid tumors were enrolled in the study. During the screening period, patients received standard of care PD-1-based immunotherapies appropriate for their tumor type. Subsequently, patients were immunized with GEN-009 with additional doses administered at 3, 6, 12, and 24 weeks. Peripheral blood mononuclear cells (PBMCs) were collected at baseline, pre-vaccination (D1), as well as 29, 50, 92, and 176 days post first dose. Vaccine-induced immunogenicity and persistence were assessed by quantifying neoantigen-specific T cell responses in ex vivo and in vitro stimulation dual-analyte fluorospot assays. Polyfunctionality of neoantigen-specific T cells was evaluated by intracellular cytokine staining. Additionally, potential correlations between the ATLAS-identified profile and vaccine-induced immunogenicity were assessed.ResultsGEN-009 augmented T cell responses in 100% of evaluated patients, attributable to vaccine and not checkpoint blockade. Furthermore, neoantigen-induced secretion of IFNγ and/or TNFα by PBMCs, CD4+, and CD8+ T cells was observed in all patients. Responses were primarily from polyfunctional TEM cells and detectable in both CD4+ and CD8+ T cell subsets. Some patients had evidence of epitope spreading. Unique response patterns were observed for each patient with no apparent relationship between tumor types and time to emergence, magnitude or persistence of response. Ex vivo vaccine-induced immune responses were observed as early as 1 month, and in some cases, persisted for 176 days. Clinical efficacy possibly attributable to GEN-009 was observed in several patients, but no correlation has yet been identified with neoantigen number or magnitude of immune response.ConclusionsATLAS empirically identifies stimulatory neoantigens using the patient‘s own immune cells. GEN-009, which is comprised of personalized, ATLAS-identified neoantigens, elicits early, long-lasting and polyfunctional neoantigen-specific CD4+ and CD8+ T cell responses in individuals with advanced cancer. Several patients achieved clinical responses that were possibly attributable to vaccine; efforts are underway to explore T cell correlates of protection. These data support that GEN-009, in combination with checkpoint blockade, represents a unique approach to treat solid tumors.AcknowledgementsWe are grateful to the patients and their families who consented to participate in the GEN-009-101 clinical trial.Trial RegistrationNCT03633110Ethics ApprovalThis study was approved by Western Institutional Review Board, approval number 1-1078861-1. All subjects contributing samples provided signed individual informed consent.ReferenceDeVault V, Starobinets H, Adhikari S, Singh S, Rinaldi S, Classon B, Flechtner J, Lam H. Inhibigens, personal neoantigens that drive suppressive T cell responses, abrogate protection of therapeutic anti-tumor vaccines. J. Immunol 2020; 204(1 Supplement):91.15.

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Detection of IFNγ-Secreting CD4+ and CD8+ Memory T Cells in COVID-19 Convalescents after Stimulation of Peripheral Blood Mononuclear Cells with Live SARS-CoV-2

Viruses ◽

10.3390/v13081490 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1490

Author(s):

Victoria Matyushenko ◽

Irina Isakova-Sivak ◽

Igor Kudryavtsev ◽

Arina Goshina ◽

Anna Chistyakova ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Memory T Cells ◽

Natural Infection ◽

Intracellular Cytokine Staining ◽

T Cell Responses ◽

Effector Memory ◽

Memory T Cell ◽

Cell Responses ◽

Stimulation Of

Background: New coronavirus SARS-CoV-2, a causative agent of the COVID-19 pandemic, has been circulating among humans since November 2019. Multiple studies have assessed the qualitative and quantitative characteristics of virus-specific immunity in COVID-19 convalescents, however, some aspects of the development of memory T-cell responses after natural SARS-CoV-2 infection remain uncovered. Methods: In most of published studies T-cell immunity to the new coronavirus is assessed using peptides corresponding to SARS-CoV-1 or SARS-CoV-2 T-cell epitopes, or with peptide pools covering various parts of the viral proteins. Here, we determined the level of CD4+ and CD8+ memory T-cell responses in COVID-19 convalescents by stimulating PBMCs collected 1 to 6 months after recovery with sucrose gradient-purified live SARS-CoV-2. IFNγ production by the central and effector memory helper and cytotoxic T cells was assessed by intracellular cytokine staining assay and flow cytometry. Results: Stimulation of PBMCs with live SARS-CoV-2 revealed IFNγ-producing T-helper effector memory cells with CD4+CD45RA−CCR7− phenotype, which persisted in circulation for up to 6 month after COVID-19. In contrast, SARS-CoV-2-specific IFNγ-secreting cytotoxic effector memory T cells were found at significant levels only shortly after the disease, but rapidly decreased over time. Conclusion: The stimulation of immune cells with live SARS-CoV-2 revealed a rapid decline in the pool of effector memory CD8+, but not CD4+, T cells after recovery from COVID-19. These data provide additional information on the development and persistence of cellular immune responses after natural infection, and can inform further development of T cell-based SARS-CoV-2 vaccines.

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Characterisation of CD154+ T cells following ex vivo allergen stimulation illustrates distinct T cell responses to seasonal and perennial allergens in allergic and non-allergic individuals

BMC Immunology ◽

10.1186/1471-2172-14-49 ◽

2013 ◽

Vol 14 (1) ◽

pp. 49 ◽

Cited By ~ 4

Author(s):

Karen A Smith ◽

Nicola J Gray ◽

Femi Saleh ◽

Elizabeth Cheek ◽

Anthony J Frew ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Ex Vivo ◽

T Cell Responses ◽

Cell Responses ◽

Perennial Allergens

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153 NEO-PTC-01 (BNT-221), an autologous neoantigen-specific T-cell product for adoptive cell therapy of metastatic melanoma

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0153 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A167-A167

Author(s):

Divya Lenkala ◽

Jessica Kohler ◽

Brian McCarthy ◽

Michael Nelson ◽

Jonathan McGee ◽

...

Keyword(s):

T Cell ◽

Metastatic Melanoma ◽

Ex Vivo ◽

Adoptive Cell Therapy ◽

T Cell Responses ◽

Process Engineering ◽

High Quality ◽

Cell Product ◽

Cell Responses ◽

Melanoma Patients

BackgroundNeoantigens are tumor-specific antigens that are important in the anti-tumor immune response. These antigens are not subject to central immune tolerance and are therefore potentially more immunogenic than tumor-associated antigens. NEO-STIM®, our propriety ex vivo induction process, was developed to generate T-cell products specific to these neoantigens from the peripheral blood of patient. Here, we present the results of a proof of concept, pre-clinical study with multiple successful process engineering runs generating a neoantigen-specific T-cell product (NEO-PTC-01) using leukaphereses from metastatic melanoma patients. These products contain specific T-cell responses targeting multiple neoantigens from each individual patient‘s tumor.MethodsPatient-specific neoantigens were predicted using our RECON® bioinformatics platform. Predicted high-quality neoantigens were utilized in our ex vivo stimulation protocol, NEO-STIM, in the process engineering runs of NEO-PTC-01. NEO-STIM is used to prime, activate and expand memory and de novo T-cell responses from both the CD4+ and the CD8+ compartment. High throughput flow cytometric analysis was performed to characterize the specificity and functionality (cytokine production and cytolytic capacity) of the induced T-cell responses.ResultsHere we present the successful induction of 4–5 CD8+ and 4–7 CD4+ T-cell responses per patient, generated using peripheral blood mononuclear cells from multiple melanoma patients during these successful process engineering runs. We then extensively characterized these T-cell responses and demonstrate that these responses are functional, specific and have cytolytic capacity. Moreover, the induced T cells can recognize autologous tumor.ConclusionsNEO-STIM is a novel platform that generates ex vivo T-cell responses to high-quality neoantigen targets. NEO-PTC-01, the neoantigen-specific T cell product generated from this process, is a potent adoptive cell therapy targeting multiple immunogenic neoantigens in patients with metastatic melanoma.

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