The adaptive immune repertoire plays a critical role in type 1 diabetes (T1D) pathogenesis. However, efforts to characterize B cell and T cell receptor (TCR) profiles in T1D subjects have been ...largely limited to peripheral blood sampling and restricted to known antigens. To address this, we collected pancreatic draining lymph nodes (pLN), "irrelevant" nonpancreatic draining lymph nodes, peripheral blood mononuclear cells (PBMC), and splenocytes from T1D subjects (
= 18) and control donors (
= 9) as well as pancreatic islets from 1 T1D patient; from these tissues, we collected purified CD4
conventional T cells (Tconv), CD4
Treg, CD8
T cells, and B cells. By conducting high-throughput immunosequencing of the TCR β chain (
) and B cell receptor (BCR) immunoglobulin heavy chain (
) on these samples, we sought to analyze the molecular signature of the lymphocyte populations within these tissues and of T1D. Ultimately, we observed a highly tissue-restricted CD4
repertoire, while up to 24% of CD8
clones were shared among tissues. We surveyed our data set for previously described proinsulin- and glutamic acid decarboxylase 65-reactive (GAD65-reactive) receptors, and interestingly, we observed a TRB with homology to a known GAD65-reactive TCR (clone GAD4.13) present in 7 T1D donors (38.9%), representing >25% of all productive TRB within Tconv isolated from the pLN of 1 T1D subject. These data demonstrate diverse receptor signatures at the nucleotide level and enriched autoreactive clones at the amino acid level, supporting the utility of coupling immunosequencing data with knowledge of characterized autoreactive receptors.
The SARS-CoV-2 Omicron variant of concern (VoC) and its sublineages contain 31–36 mutations in spike and escape neutralization by most therapeutic antibodies. In a pseudovirus neutralization assay, ...66 of the nearly 400 candidate therapeutics in the Coronavirus Immunotherapeutic Consortium (CoVIC) panel neutralize Omicron and multiple Omicron sublineages. Among natural immunoglobulin Gs (IgGs), especially those in the receptor-binding domain (RBD)-2 epitope community, nearly all Omicron neutralizers recognize spike bivalently, with both antigen-binding fragments (Fabs) simultaneously engaging adjacent RBDs on the same spike. Most IgGs that do not neutralize Omicron bind either entirely monovalently or have some (22%–50%) monovalent occupancy. Cleavage of bivalent-binding IgGs to Fabs abolishes neutralization and binding affinity, with disproportionate loss of activity against Omicron pseudovirus and spike. These results suggest that VoC-resistant antibodies overcome mutagenic substitution via avidity. Hence, vaccine strategies targeting future SARS-CoV-2 variants should consider epitope display with spacing and organization identical to trimeric spike.
Display omitted
•66/397 of CoVIC IgGs raised against earlier SARS-CoV-2 also neutralize Omicron•14 of these recognize epitopes conserved in Omicron•Most others recognize highly mutated epitopes, retaining activity by binding bivalently•Cleavage of bivalent binding IgGs to Fabs abolishes Omicron neutralization
Callaway et al. examine a panel of 397 SARS-CoV-2 antibodies to understand how some antibodies, generated early during the COVID-19 pandemic, maintain the ability to neutralize Omicron variants despite extensive mutation in their epitopes. Antibodies against highly mutated epitopes retain neutralization by binding bivalently: cleavage to Fab eliminates neutralization.
Abstract
Background: Detection of MRD is an important predictor of patient outcome following treatment of B-ALL; importantly, MRD is emerging as a useful tool to detect early relapse, which may ...fulfill a key previously unmet clinical need. Objective: To evaluate the potential of MRD to predict morphologic relapse in pediatric and AYA patients with B-ALL.
Methods: Bone marrow (BM) and peripheral blood (PB) specimens at screening (pre-tisagenlecleucel infusion), post-infusion, and relapse from two B-ALL clinical trials (ELIANA NCT02435849 and ENSIGN NCT02228096) were tested using immunoglobulin next-generation sequencing (IgNGS) and flow cytometry (FC). We assessed concordance between two MRD assays to determine which method could support early relapse detection and whether using PB with IgNGS was comparable with BM testing with FC.
Results: IgNGS was performed in 300 samples from 88 patients. 237 samples from 83 patients also had FC MRD results available. Baseline samples, which had high disease burden, showed 100% MRD concordance between both assays. However, post-treatment, where the leukemic burden was dramatically reduced, IgNGS detected a greater number of MRD-positive samples vs FC at each sensitivity level tested (10-4, 10-5, and 10-6). At the highest sensitivity level of 10-6, IgNGS was able to detect 18% more MRD-positive post-treatment samples. IgNGS was able to detect MRD positivity 1-4 months ahead of clinical relapse in a small number of relapsed patients, whether relapse was CD19+ or CD19-. MRD burden in BM was higher than in PB using both FC and IgNGS. In patients with matching data available, IgNGS was able to detect more MRD-positive PB samples than FC MRD-positive BM samples. Patients who were MRD negative by both IgNGS and FC at the end of first month post-infusion had better progression-free survival (PFS) and overall survival (OS) compared with those with detectable MRD. Tumor clonality at baseline and clonal evolution following tisagenlecleucel treatment will be presented.
Conclusion: MRD detection using IgNGS in PB may be used as a surrogate for FC assessment of MRD in BM. Patients who were MRD negative by IgNGS 1 month after infusion had improved PFS and OS vs those with detectable MRD; ongoing studies will provide further information on the applicability of IgNGS MRD detection and its association with long-term outcome in tisagenlecleucel-treated pediatric and AYA relapsed/refractory B-ALL patients.
Citation Format: Michael A. Pulsipher, Xia Han, Máire Quigley, Gabor Kari, Susana Rives, Theodore W. Laetsch, Gary D. Myers, Hidefumi Hiramatsu, Gregory A. Yanik, Muna Qayed, Timothy Driscoll, Michael W. Boyer, Heather Stefanski, Jochen Buchner, Andre Baruchel, Peter Bader, Lan Yi, Creton Kalfoglou, Harlan Robins, Erik Yusko, Gullu Gorgun, Eric Bleickardt, Stephane Wong, Stephan A. Grupp. Potential utility of minimal residual disease (MRD) to identify relapse in pediatric and young adult (AYA) B-cell acute lymphoblastic leukemia (B-ALL) patients treated with tisagenlecleucel abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT077.
Peripheral T-cell lymphomas (PTCLs) have marked biologic and clinical heterogeneity, which confounds treatment decisions. Advances in circulating tumor DNA (ctDNA) assays using next-generation ...sequencing (NGS) have improved the detection of molecular relapse and driver mutations in diffuse large B-cell lymphoma and show the potential utility of ctDNA across lymphomas. We investigated NGS-based monitoring of T-cell receptor (TCR) sequences in patients with PTCL undergoing frontline treatment. Of 45 patients, 34 (76%) had tumor-specific clonotypes of the TCRβ or TCRγ genes identified, which included 18 (86%) from baseline tissue and 16 (67%) from baseline serum. Twenty-five (74%) patients had both TCRβ and TCRγ clonotypes, 23 (68%) had more than 1 TCRγ clonotype, and 4 (9%) had multiple TCRβ or TCRγ clonotypes, demonstrating significant intrapatient clonotypic heterogeneity. Among 24 patients with available serial serum samples during treatment, 9 (38%) cleared ctDNA after 2 cycles of therapy, and 11 (46%) had detectable ctDNA at the end of treatment. Patients with detectable ctDNA after therapy showed a trend toward worse survival. Notably, 2 patients with persistently detectable ctDNA after therapy remained in remission with 10 years of follow-up. Clonotypic heterogeneity in tumors and persistence, despite long-term remission, suggests variability in oncological potential. This trial was registered at www.clinicaltrials.gov as #NCT00001337.
•NGS of the T-cell receptor identifies dominant clonotypes in most patients with untreated PTCL, which can be tracked in peripheral blood.•Marked clonotypic heterogeneity of the TCR, which may underpin treatment resistance, is present within individual patients with PTCL.
Display omitted
Abstract only
1030
Background: Previous studies have shown that 44-71% of trastuzumab (T)-treated pts develop HER2-specific immunity (Clin Cancer Res 2007, 13:5133; Cancer Res 2016, 76:3702; Breast ...Cancer Res 2018, 20:52). M is an Fc-engineered mAb that shares similar HER2 binding and antiproliferative activity as T. The Fc region of M has been engineered for increased affinity to the activating FcγRIIIA (CD16A) and lower binding to the inhibitory FcγRIIB (CD32B), attributes that may enhance the mAb’s immune function, such as antigen presentation. Methods: HER2+ cancer pts who progressed on prior therapy received M (0.1-6 mg/kg QW for 3 of every 4 weeks N = 34; or 10-18 mg/kg Q3W N = 32) in phase 1 trial NCT01148849. PBMC and plasma were collected pre-dose and 50 days post-dose for 46 pts and > 4 years for 3 pts on long-term treatment. Response to HER2 or control antigens (Ag) was assessed by IFNγ ELISpot and antibody (Ab) ELISA. In 14 pts, T-cell antigen receptor (TCR) repertoire was assessed by immunosequencing. Results: Following M treatment, mean frequencies of IFNγ-producing T cells specific for intra- or extracellular fragments of HER2 increased by 2.5 to 6-fold (p < 0.0027, paired t test). Most (95%) of subjects responded to ≥2 of 6 (median = 5) HER2 Ag. Mean HER2-specific Ab concentration increased by 19-54% (p < 0.0001), with all subjects responding to ≥2 (median = 5) of the 6 Ag. A small 1.6-fold increase in IFNγ response to control CMV/EBV/Flu (but not tetanus or cyclin D1) peptides was observed; no increase in Ab response to control Ag was noted. Subsets of HER2-specific T-cell and Ab responses persisted during long-term treatment. Median TCR clonality increased by 54% (p = 0.003), with an average of 125 unique clones expanding, while overall TCR diversity remained unchanged (p = 0.19). Conclusions: Treatment of HER2+ cancer with M was associated with enhanced HER2-specific T-cell and Ab responses together with increased TCR clonality, indicative of a more focused T-cell repertoire. The high frequency of HER2-specific immunity in M-treated patients ( > 95%) is consistent with its enhanced Fc region contributing to linkage of innate and adaptive immune responses.
Mantle cell lymphoma (MCL) is biologically and clinically heterogeneous and would benefit from prognostic biomarkers to guide management. Circulating tumor DNA (ctDNA) is a novel prognostic biomarker ...in diffuse large B-cell lymphoma that may have applicability in MCL. We analyzed ctDNA dynamics in previously untreated patients with MCL who received induction therapy with bortezomib and DA-EPOCH-R for 6 cycles followed by random assignment to observation or bortezomib maintenance in responding patients in a prospective phase 2 study. Most patients also underwent initial treatment window of bortezomib alone prior to induction. Serum was collected pretreatment, after the window, after cycles 1 and 2, at the end of induction, and at each follow-up visit along with restaging computed tomography scans. Next-generation sequencing was used to identify and quantify ctDNA encoding the immunoglobulin receptor sequences in serum as markers of minimal residual disease. Fifty-three patients were enrolled, with a median follow-up of 12.7 years. Patients without detectable ctDNA after 2 cycles of induction had longer progression-free survival (PFS) and overall survival (OS) compared with those with detectable ctDNA (median PFS, 2.7 vs 1.8 years; overall P = .005; median OS, 13.8 vs 7.4 years; overall P = .03). Notably, in vivo assessment of ctDNA dynamics during the bortezomib window was not prognostic, and there was no difference in PFS or OS with bortezomib maintenance. ctDNA monitoring after induction showed that molecular relapse preceded clinical relapse in some cases. In conclusion, interim ctDNA negativity strongly correlates with improved survival and supports the investigation of response-adapted strategies. This trial was registered at www.clinicaltrials.gov as #NCT00114738.
•Early changes in ctDNA dynamics are prognostic in untreated MCL.•Bortezomib maintenance after bortezomib-based induction therapy does not improve outcome in untreated MCL.
Display omitted
Introduction
Detection of minimal residual disease (MRD) is an important predictor of patient outcome following treatment of B-cell acute lymphoblastic leukemia (B-ALL). We assessed concordance ...between two MRD assays, with different assay sensitivities, to determine which MRD detection method could support early relapse detection. Immunoglobulin next generation sequencing (Ig NGS) and flow cytometry (FC) were tested in samples from two clinical trials ELIANA (NCT02435849) and ENSIGN (NCT02228096) for pediatric relapsed and refractory B-ALL patients treated with tisagenlecleucel. We also assessed whether using blood with Ig NGS would be comparable to BM testing with FC. Finally we analyzed whether clonal evolution, as detected by Ig NGS, occurred during of the course of therapy for both CD19+ and CD19- relapse patients.
Methods
In this analysis, bone marrow and peripheral blood specimens at screening (pre-tisagenlecleucel infusion), post-infusion and relapse were tested. Ig NGS was performed in 300 samples from 88 patients. 237 samples from 83 patients also had FC MRD results available.
MRD was measured on fresh blood and bone marrow using a 3-tube FC assay (CD10, CD19, CD13, CD20, CD22, CD33, CD34, CD38, CD45, CD58, CD123). The FC MRD assay has a lower limit of sensitivity of 0.01% of white blood cells.
Ig NGS detection of MRD was performed using the Adaptive Biotechnology's NGS MRD assay. MRD quantitative values, along with the qualitative MRD calls at each assay sensitivity level (10-4, 10-5 and 10-6) were reported. At baseline, 85 out of 88 samples had informative clones.
Results and Conclusions
To examine the comparability of flow cytometry and Ig NGS methods in assessing MRD, baseline and post-treatment samples were tested. Baseline samples, which had a high disease burden, showed 100% MRD concordance between both assays. However, post-treatment, where the leukemic burden was dramatically reduced, Ig NGS detected a greater number of MRD positive samples compared to FC, at each sensitivity level tested (10-4, 10-5 and 10-6). At the highest sensitivity level of 10-6, Ig NGS was able to detect 18% more MRD positive post-treatment samples. Importantly, Ig NGS was able to detect MRD positivity 1-4 months ahead of clinical relapse in a small number of relapsed patients, whether relapse was CD19+ or CD19-. This may provide an important window of opportunity for pre-emptive treatment while a patients' tumor burden is still low.
In B-ALL, it has previously been described that MRD levels can be one to three logs lower in blood compared to bone marrow (VanDongen JJ et al. Blood 2015). Our results support these findings whereby MRD burden in bone marrow was higher than in blood using both FC and Ig NGS. We next set out to determine if the increased sensitivity afforded by the Ig NGS assay could provide a level of MRD detection in the blood comparable to FC in the bone marrow. In patients with matching data available, Ig NGS was able to detect more MRD positive blood samples than FC MRD positive bone marrow samples. This suggests that monitoring of MRD using Ig NGS in the blood holds the potential to be used as a surrogate for FC MRD in bone marrow.
The relationship between MRD and prognosis was examined. Patients who were MRD negative by both Ig NGS and FC at the end of first month post-infusion had better progression-free survival and overall survival compared to those with detectable MRD.
Tumor clonality will be further analyzed to understand sub-clone composition at baseline and clonal evolution following tisagenlecleucel treatment.
Taken together, these results highlight the importance of using a highly sensitive assay, such as Ig NGS, when monitoring for MRD. MRD detection by Ig NGS holds the potential to identify early response/relapse in patients, which could provide a window of opportunity for additional intervention before morphological relapse. Ongoing studies with larger patient groups will provide further information on the applicability of Ig NGS MRD detection and its association with long-term outcome in tisagenlecleucel-treated pediatric r/r B-ALL patients.
Pulsipher:Novartis: Consultancy, Honoraria, Speakers Bureau; CSL Behring: Consultancy; Amgen: Honoraria; Adaptive Biotech: Consultancy, Research Funding. Han:Novartis Pharmaceuticals Corporation: Employment, Equity Ownership. Quigley:Novartis Pharmaceuticals Corporation: Employment. Kari:Adaptimmune LLC: Other: previous employment within 2 years; Novartis Pharmaceuticals Corporation: Employment. Rives:Shire: Consultancy, Other: Symposia, advisory boards ; Amgen: Consultancy, Other: advisory board ; Novartis Pharmaceuticals Corporation: Consultancy, Other: Symposia, advisory boards ; Jazz Pharma: Consultancy, Other: Symposia, advisory boards . Laetsch:Bayer: Consultancy; Eli Lilly: Consultancy; Pfizer: Equity Ownership; Novartis Pharmaceuticals Corporation: Consultancy; Loxo Oncology: Consultancy. Myers:Novartis Pharmaceuticals Corporation: Consultancy, Honoraria, Research Funding, Speakers Bureau. Qayed:Novartis: Consultancy. Stefanski:Novartis Pharmaceuticals Corporation: Consultancy, Honoraria, Speakers Bureau. Baruchel:Shire: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; Servier: Consultancy; Roche: Consultancy; Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Travel, accommodations or expenses; Celgene: Consultancy. Bader:Cellgene: Consultancy; Riemser: Research Funding; Medac: Patents & Royalties, Research Funding; Neovii: Research Funding; Novartis: Consultancy, Speakers Bureau. Yi:Novartis Pharmaceuticals Corporation: Employment. Kalfoglou:Novartis Pharmaceuticals Corporation: Employment. Robins:Adaptive Biotechnologies: Consultancy, Employment, Equity Ownership, Patents & Royalties. Yusko:Adaptive Biotechnologies: Employment, Equity Ownership. Görgün:Novartis Pharmaceuticals Corporation: Employment. Bleickardt:Novartis Pharmaceuticals Corporation: Employment. Wong:Novartis Pharmaceuticals Corporation: Employment, Equity Ownership. Grupp:Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy; Adaptimmune: Consultancy; University of Pennsylvania: Patents & Royalties.
Abstract only
11500
Background: The mechanisms underlying resistance to immune checkpoint blockade are poorly understood. Major efforts have been made to understand how mutations, through generation ...of neoantigens, may alter tumor immunogenicity and anti-tumor responses, particularly through T cell responses. However, the T cell repertoire and its interaction with cancers bearing specific molecular alterations have not been systemically studied. Methods: We delineated the landscapes in the T cell receptor (TCR) repertoire, immune infiltration (immunohistochemistry using multiple immune markers), genome (exome sequencing), epigenome (methylation array) and transcriptome (mRNA gene expression array) of 254 resected non-small cell lung cancers (NSCLC), matched normal lung tissues and peripheral blood mononuclear cells (PBMC). We report herein the preliminary analyses of TCR sequencing of NSCLC tumors and matched normal lung tissues. Results: We observed that: 1) Smaller tumors (smaller than median) had a higher T cell infiltrate (p = 0.0016) and higher entropy than larger tumors (p = 0.0098); 2) Tumors from ever/current smokers had higher T cell clonality than former/never-smokers (p = 0.005); 3) TCR clonality was positively correlated with mutational burden (p = 0.0026); 4) Compared to tumors, normal lung tissues demonstrated significantly less T cell infiltration (p = 2.1x10^-11), but a significantly higher clonality (p = 3.9x10^-7). Finally, many T cell clones, including major clones were shared between normal lung tissues and matched NSCLC tumors. Conclusions: Our preliminary data demonstrate the distinct immune microenvironment in different NSCLC tumors may be associated with particular clinicopathological features. The higher TCR clonality in normal lung tissues and overlap of T cell clones between normal lung and NSCLC tumors implies a significant proportion of tumor infiltrating T cells may be a function of constant exposure to mutagens rather than an anti-tumor response. Analysis of the peripheral TCR repertoire, the molecular landscape of these tumors and the association with immune profiling is underway.
PDF
