Imiquimod: A TLR-7 agonist as adjuvant for a recombinant protein cancer vaccine

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 8545-8545
Author(s):  
S. Adams ◽  
D. O'Neill ◽  
D. Nonaka ◽  
O. Manches ◽  
L. Chiriboga ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Intracellular Cytokine Staining ◽  
T Cell Responses ◽  
Protein Vaccine ◽  
Imiquimod Cream ◽  
Antigen Uptake ◽  
Cell Responses ◽  
Cell Immunity

8545 Purpose: This clinical trial evaluates the safety and adjuvant activity of imiquimod, a toll-like receptor (TLR)-7 agonist, when given with a NY-ESO-1 protein vaccine. Imiquimod, by locally activating and recruiting dendritic cells (DCs) into the skin, is expected to stimulate antigen uptake by DCs, induce maturation and migration to draining lymph nodes, and to induce antigen-specific T and B cell immunity. Methods: Pilot study; 9 patients with resected stage 2B-3C malignant melanoma. Four 21 day cycles consisted of topical imiquimod cream (250 mg) on days 1–5 and id. injected NY-ESO-1 protein (100 mcg) into the site on day 3. Blood was drawn at several time points for immune monitoring; skin punch biopsies were obtained from control, imiquimod and vaccination sites 48 hours after the last vaccination. Results: The regimen was tolerated well, all patients completed four vaccinations. AEs were mild and transient and included injection site reactions (8/9 patients), fatigue (4/9 patients) and fever (2/9 patients). Significant levels of antigen-specific CD4+ or CD8+ T cell responses were not detected in ex-vivo ELISPOT assays. However, intracellular cytokine staining assays after in vitro pre-stimulation indicated that 6 of 8 subjects developed NY-ESO-1 CD4+ T cell responses. Humoral immunity was manifest by the induction of anti-NY-ESO-1 antibodies in 7/9 patients post-vaccination. Histochemistry of skin sections showed significant dermal mononuclear cell infiltrates in Imiquimod treated skin, whereas none were seen in untreated skin (p<0.01). IHC revealed markedly increased numbers of CD3+ (T-cells), CD68+ (macrophages/monocytes), CD123+ (plasmacytoid DCs) and DC-LAMP+ (mature myeloid DCs) immune cells in Imiquimod treated skin when compared with control skin of the same patients (p<0.05). Conclusion: Imiquimod, a topical immune response modifier, generated clear inflammatory infiltrates in the dermis, with significant increases in antigen-presenting cells and T cells. Imiquimod was well tolerated when used as an adjuvant to an NY-ESO-1 protein vaccine. Systemic immunity of both humoral and cellular types was induced in the majority of patients; however, responses were weak and the vaccine combination needs to be optimized in future studies. No significant financial relationships to disclose.

scholarly journals Safety and exceptional immunogenicity of novel 5T4 viral vectored vaccination regimes in early stage prostate cancer: a phase I clinical trial

2020 ◽  
Author(s):  
Federica Cappuccini ◽  
Richard Bryant ◽  
Emily Pollock ◽  
Lucy Carter ◽  
Clare Verrill ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Early Stage ◽  
Specific Antigen ◽  
T Cell Responses ◽  
Cell Responses ◽  
Cell Immunity

AbstractProstate cancer (PCa) has been under investigation as a target for antigen-specific immunotherapies in metastatic disease settings for a decade. However, neither of the two clinically most developed prostate cancer vaccines, Sipuleucel-T and ProstVac, induce strong T cell immunity. In this first-in-man study, VANCE, we evaluated a novel vaccination platform based on two replication-deficient viruses, chimpanzee adenovirus (ChAd) and MVA (Modified Vaccinia Ankara), targeting the oncofetal self-antigen 5T4 in early stage PCa. Forty patients, either newly diagnosed with early stage prostate cancer and scheduled for radical prostatectomy or patients with stable disease on an active surveillance protocol, were recruited to the study to assess the vaccine safety and T cell immunogenicity. Secondary and exploratory endpoints included immune infiltration into the prostate, prostate specific antigen (PSA) change and assessment of phenotype and functionality of antigen-specific T cells. The vaccine had an excellent safety profile. Vaccination-induced 5T4-specific T cell responses were measured in blood by ex vivo IFN-γ ELISpot and were detected in the majority of patients with a mean level in responders of 198 spot-forming cells (SFC) per million peripheral blood mononuclear cells (PBMCs). Flow cytometry analysis demonstrated the presence of both CD8+ and CD4+ polyfunctional 5T4-specific T cells in the circulation. 5T4-reactive tumour infiltrating lymphocytes (TILs) were isolated from post-treatment prostate tissue. Some of the patients had a transient PSA rise 2-8 weeks following vaccination, possibly indicating an inflammatory response in the target organ. The potent T cell responses elicited support the evaluation of these vectored vaccine in efficacy trials.

HLA-Class I Alleles Impact Susceptibility To EBV+ Classical Hodgkin Lymphoma By Altering EBV Latent Antigen-Specific CD8+ T-Cell Immune Hierarchies

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 630-630
Author(s):  
Maher K Gandhi ◽  
Rebekah M Brennan ◽  
Leesa Wockner ◽  
Pratip K Chattopadhyay ◽  
Mario Roederer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Hla Class I ◽  
Cd8 T Cell ◽  
T Cell Immunity ◽  
Class I ◽  
Cell Responses ◽  
Cell Immunity

Abstract In Epstein-Barr virus (EBV) classical Hodgkin lymphoma (EBV+ cHL), Hodgkin-Reed Sternberg cell antigen presentation is intact, with viral expression restricted to sub-dominant latent-antigens including LMP1/2A. Large epidemiological studies have reported differential HLA-class I (HLA-I) susceptibility to EBV+ cHL. The functional basis for these observations is unknown. HLA-I molecules present viral peptides for recognition by CD8+ T-cells, and it may be that the relative risk of developing EBV+ cHL is due to HLA-I alleles influencing the magnitude of CD8+ T-cell immunity against relevant EBV-specific antigens. However this remains speculative, with immunological evidence lacking. Several non-HLA-I linked genetic susceptibility loci have been identified, and HLA-I associations may simply represent markers for genes of diverse functions that are in linkage disequilibrium to the HLA-I region. We undertook an Australasian Leukaemia and Lymphoma Group study to address this fundamental question, utilizing 4 distinct but complimentary experimental approaches. 1. 9 EBV+ cHL and 11 EBV-ve cHL pre-therapy PBMC samples were tested for ex-vivo IFNγ, TNFα and CD107a CD8+ T-cell immunity, using overlapping LMP1 and LMP2A peptide pools. The non-HRS expressed EBV-lytic protein BZLF1 was a control. Highly stringent FACS gating was used to maximize specificity. Results were interrogated using Profile and SPICE analysis. Interestingly IFNγ, TNFα and CD107 CD8+ T-cell responses in HLA-A*02 EBV+ cHL (but not EBV-ve cHL) patients were greater than non-HLA-A*02 (LMP1 p=0.002; LMP2A p=0.03; combined LMP1/LMP2A p=0.005), whereas BZLF1 was equivalent, indicating that HLA-I provides differential CD8+ T-cell immunity against relevant EBV-latent antigens in EBV+ cHL but not EBV-ve cHL. 2. However, up to 4 different HLA-A/B molecules can potentially present relevant EBV-derived epitopes in each individual, adding a confounding layer of complexity to single allele-based effects. To overcome this and enhance sensitivity, we used the mutant HLA-I 721.221 cell-line (pulsed with LMP2A), transfected with either HLA-A*01, HLA-A*02, HLA-A*03 or HLA-B*08 alleles, as antigen presenting cells to in-vitro expand LMP2A-specific CD8+ T-cells from HLA-A*02 heterozygotes. This found ∼90% of the HLA-I LMP2A response was restricted through HLA-A*02. 3. In contrast to EBV+ cHL, in EBV-post-transplant lymphoproliferative disorders (EBV+ PTLD) the immunogenic EBNA3A/3B/3C latent-antigens are expressed. We compared HLA-I associations in 110 cHL (35% EBV+ cHL) to 153 PTLD (63% EBV+ PTLD) patients. Using Bonferoni corrected statistics, we confirmed that HLA-A*02 and HLA-A*01 homozygotes had lower and higher susceptibility to EBV+ cHL respectively, and that HLA-B*37 was positively associated. Notably, no HLA-I associations with EBV+ PTLD were found. 4. To investigate the impact of HLA-I on the hierarchy of CD8+ T-cell immunity to sub-dominant (LMP1/2A) and immune-dominant (EBNA3A/3B/3C) EBV-latent proteins, we analysed the diversity of HLA-class I restricted T-cells in 30 healthy EBV+ participants. To supplement 30 ‘defined' (i.e. validated) HLA-I EBV-latent antigen epitopes and expand HLA-I coverage, we identified 31 ‘SYFPEITHI' bioinformatically ‘predicted' peptide epitopes for HLA-A*01, HLA-A*03 or HLA-B*37 restricted EBV-latent antigens. All SYFPEITHI scores were ≥21, and thermal stability circular dichroism analysis (HLA-A*01) or MHC stabilization assays on T2 cells (HLA-A*03) confirmed peptide binding to HLA-I. Ex-vivo CD107 CD8+ T-cell assays for the 61 peptides, found that sub-dominant LMP1/2A-specific peptide responses were largely confined to HLA-A*02 (Fig 1A), whilst immuno-dominant CD8+ T-cell responses were stimulated by peptides presented by numerous HLA-I alleles (Fig 1B). These data combined illustrate that differential HLA-I-associated susceptibility to EBV+ cHL reflects altered EBV latent antigen-specific CD8+ T-cell immune hierarchies. For lymphomas expressing a restricted set of poorly immunogenic proteins, even modest CD8+ T-cell responses against relevant tumor-associated proteins confer protection, with broad implications for EBV-vaccine design. Studies are required to determine if similar mechanisms are applicable to non-lymphoid EBV+ malignancies with restricted latency such as undifferentiated nasopharngeal carcinoma. Disclosures: No relevant conflicts of interest to declare.

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

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

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

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.

538 Harnessing cross-dressing dendritic cells to strengthen anti-tumor immunity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A574-A574
Author(s):  
Ellen Duong ◽  
Timothy Fessenden ◽  
Arjun Bhutkar ◽  
Stefani Spranger
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cancer Cell ◽  
Tumor Immunity ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Cell Responses ◽  
Cell Immunity ◽  
Cross Dressing

BackgroundCytotoxic (CD8+) T-cells are required for tumor eradication and durable anti-tumor immunity.1 The induction of tumor-reactive CD8+ T-cells is predominately attributed to a subset of dendritic cells (DC) called Batf3-driven DC1, given their robust ability to cross-present antigens for T-cell priming and their role in effector T-cell recruitment.2–4 Presence of the DC1 signature in tumors correlates with improved survival and response to immunotherapies.5–7 Yet, most tumors with a DC1 infiltrate still progress, suggesting that while DC1 can initiate tumor-reactive CD8+ T-cell responses, they are unable to sustain them. Therefore, there is a critical need to identify and engage additional stimulatory DC subsets to strengthen anti-tumor immunity and boost immunotherapy responses.MethodsTo identify DC subsets that drive poly-functional CD8+ T-cell responses, we compared the DC infiltrate of a spontaneously regressing tumor with a progressing tumor. Multicolor flow immunophenotyping and single-cell RNA-sequencing were used to profile the DC compartment of both tumors. IFNγ-ELISpot was performed on splenocytes to assess for systemic tumor-reactive T-cell responses. Sorted DC subsets from tumors were co-cultured with TCR-transgenic T-cells ex vivo to evaluate their stimulatory capacity. Cross-dressing (in vivo/ex vivo) was assayed by staining for transfer of tumor-derived H-2b MHC complexes to Balb/c DC, which express the H-2d haplotype. Protective systemic immunity was assayed via contralateral flank tumor outgrowth experiments.ResultsRegressor tumors were infiltrated with more cross-presenting DC1 than progressor tumors. However, tumor-reactive CD8+ T-cell responses and tumor control were preserved in Batf3-/- mice lacking DC1, indicating that anti-tumor immune responses could be induced independent of DC1. Through functional assays, we established that anti-tumor immunity against regressor tumors required CD11c+ DC and cGAS/STING-independent type-I-interferon-sensing. Single-cell RNA-sequencing of the immune infiltrate of regressor tumors revealed a novel CD11b+ DC subset expressing an interferon-stimulated gene signature (ISG+ DC). Flow studies demonstrated that ISG+ DC were more enriched in regressor tumors than progressor tumors. We showed that ISG+ DC could activate CD8+ T-cells by cross-dressing with tumor-derived peptide-MHC complexes, thereby bypassing the requirement for cross-presentation to initiate CD8+ T-cell-driven immunity. ISG+ DC highly expressed cytosolic dsRNA sensors (RIG-I/MDA5) and could be therapeutically harnessed by exogenous addition of a dsRNA analog to drive protective CD8+ T-cell responses in DC1-deficient mice.ConclusionsThe DC infiltrate in tumors can dictate the strength of anti-tumor immunity. Harnessing multiple stimulatory DC subsets, such as cross-presenting DC1 and cross-dressing ISG+ DC, provides a therapeutic opportunity to enhance anti-tumor immunity and increase immunotherapy responses.ReferencesFridman WH, et al. The immune contexture in human tumours: impact on clinical outcome. Nature Reviews Cancer 2012;12(4): p. 298–306.Hildner K, et al. Batf3 deficiency reveals a critical role for CD8alpha+ dendritic cells in cytotoxic T cell immunity. Science 2008;322(5904):p. 1097–100.Spranger S, et al. Tumor-Residing Batf3 dendritic cells are required for effector T cell trafficking and adoptive T cell therapy. Cancer Cell 2017;31(5):p. 711–723.e4.Roberts, EW, et al., Critical role for CD103(+)/CD141(+) dendritic cells bearing CCR7 for tumor antigen trafficking and priming of T cell immunity in melanoma. Cancer Cell 2016;30(2): p. 324–336.Broz ML, et al. Dissecting the tumor myeloid compartment reveals rare activating antigen-presenting cells critical for T cell immunity. Cancer Cell 2014;26(5): p. 638–52.Salmon H., et al., Expansion and activation of CD103(+) dendritic cell progenitors at the tumor site enhances tumor responses to therapeutic PD-L1 and BRAF inhibition. Immunity, 2016. 44(4): p. 924–38.Sánchez-Paulete AR, et al., Cancer immunotherapy with immunomodulatory anti-CD137 and Anti-PD-1 monoclonal antibodies requires BATF3-dependent dendritic cells. Cancer Discov, 2016;6(1):p. 71–9.

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

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.

scholarly journals 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 ◽  
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.

scholarly journals 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

2013 ◽  
Vol 14 (1) ◽  
pp. 49 ◽  
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

scholarly journals 248 Empiric profiling of peripheral T cell recall responses to tumor mutanomes versus in silico predictions in NSCLC patients undergoing pembrolizumab treatment ± chemotherapy

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A268-A268
Author(s):  
Madison Milaszewski ◽  
James Loizeaux ◽  
Emily Tjon ◽  
Crystal Cabral ◽  
Tulin Dadali ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Combination Therapy ◽  
In Silico ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Patient Specific ◽  
In Silico Prediction ◽  
Cell Responses ◽  
In Silico Predictions

BackgroundEffective immune checkpoint blockade (ICB) treatment is dependent on T-cell recognition of patient-specific mutations (neoantigens). Empirical identification of neoantigens ex vivo has revealed shortcomings of in silico predictions.1 To better understand the impact of ICB treatment on T cell responses and differences between in silico and in vitro methods, neoantigen-specific T cell responses were evaluated in patients with non-small cell lung cancer undergoing first-line therapy with pembrolizumab ± chemotherapy.MethodsTumor and whole blood samples were collected from 14 patients prior to and after immunotherapy; seven each in monotherapy and combination therapy cohorts. The ex vivo ATLAS™ platform was used to profile neoantigen-specific T-cell responses. Patient-specific tumor mutations identified by next-generation sequencing (NGS) were expressed individually as ATLAS clones, processed patient-specific autologous antigen presenting cells, and presented to their T cells in vitro. ATLAS-verified antigens were compared with epitope predictions made using algorithms.ResultsOn average, 150 (range 37–339) non-synonymous mutations were identified. Pre-treatment, ATLAS identified T cell responses to a median of 15% (9–25%) of mutations, with nearly equal proportions of neoantigens (8%, 5–15%) and Inhibigens™, targets of suppressive T cell responses (8%, 3–13%). The combination therapy cohort had more confirmed neoantigens (46, 20–103) than the monotherapy cohort (7, 6–79). After treatment, the median ratio of CD4:CD8 T cells doubled in the monotherapy but not combination cohort (1.2 to 2.4 v. 1.6 to 1.3). Upon non-specific stimulation, T cells from patients on combination therapy expanded poorly relative to monotherapy (24 v. 65-fold, p = 0.014); no significant differences were observed pre-treatment (22 v. 18-fold, p = 0.1578). Post-treatment, the median number of CD8 neoantigens increased in the combination therapy cohort (11 to 15) but in monotherapy were mostly unchanged (6 to 7). Across timepoints, 36% of ATLAS-identified responses overlapped. In silico analysis resulted in 1,895 predicted epitopes among 961 total mutations; among those, 30% were confirmed with ATLAS, although nearly half were Inhibigens, which could not be predicted. Moreover, 50% of confirmed neoantigens were missed by in silico prediction.ConclusionsMonotherapy and combination therapy had differential effects on CD4:CD8 T cell ratios and their non-specific expansion. A greater proportion of neoantigens was identified than previously reported in studies employing in silico predictions prior to empirical verification.2 Overlap between confirmed antigens and in silico prediction was observed, but in silico prediction continued to have a large false negative rate and could not characterize Inhibigens.AcknowledgementsWe would like to acknowledge and thank the patients and their families for participating in this study.ReferencesLam H, McNeil LK, Starobinets H, DeVault VL, Cohen RB, Twardowski P, Johnson ML, Gillison ML, Stein MN, Vaishampayan UN, DeCillis AP, Foti JJ, Vemulapalli V, Tjon E, Ferber K, DeOliveira DB, Broom W, Agnihotri P, Jaffee EM, Wong KK, Drake CG, Carroll PM, Davis TA, Flechtner JB. An empirical antigen selection method identifies neoantigens that either elicit broad antitumor T-cell responses or drive tumor growth. Cancer Discov 2021;11(3):696–713. doi: 10.1158/2159- 8290.CD-20-0377. Epub 2021 January 27. PMID: 33504579. Rosenberg SA. Immersion in the search for effective cancer immunotherapies. Mol Med 27,63(2021). https://doi.org/10.1186/s10020-021-00321-3

scholarly journals Recruitment of highly functional SARS-CoV-2-specific CD8+ T cell receptors mediating cytotoxicity of virus-infected target cells in non-severe COVID-19

2021 ◽  
Author(s):  
Karolin I. Wagner ◽  
Laura M. Mateyka ◽  
Sebastian Jarosch ◽  
Vincent Grass ◽  
Simone Weber ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Responses ◽  
Hla Class I ◽  
Cd8 T Cell ◽  
Target Cells ◽  
Cell Responses ◽  
Cell Immunity ◽  
Engineered T Cells

T cell immunity is crucial for the control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and has been widely characterized on a quantitative level. In contrast, the quality of such T cell responses has been poorly investigated, in particular in the case of CD8+ T cells. Here, we explored the quality of SARS-CoV-2-specific CD8+ T cell responses in individuals who recovered from mild symptomatic infections, through which protective immunity should develop, by functional characterization of their T cell receptor (TCR) repertoire. CD8+ T cell responses specific for SARS-CoV-2-derived epitopes were low in frequency but could be detected robustly early as well as late - up to twelve months - after infection. A pool of immunodominant epitopes, which accurately identified previous SARSCoV- 2 infections, was used to isolate TCRs specific for epitopes restricted by common HLA class I molecules. TCR-engineered T cells showed heterogeneous functional avidity and cytotoxicity towards virus-infected target cells. High TCR functionality correlated with gene signatures of T cell function and activation that, remarkably, could be retrieved for each epitope:HLA combination and patient analyzed. Overall, our data demonstrate that highly functional HLA class I TCRs are recruited and maintained upon mild SARS-CoV-2 infection. Such validated epitopes and TCRs could become valuable tools for the development of diagnostic tests determining the quality of SARS-CoV-2-specific CD8+ T cell immunity, and thereby investigating correlates of protection, as well as to restore functional immunity through therapeutic transfer of TCR-engineered T cells.

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