H3K27M neoepitope vaccination in diffuse midline glioma induces B and T cell responses across diverse HLA loci of a recovered patient

Vaccine-induced T cell receptor T cell therapy targeting a glioblastoma stemness antigen

T cell receptor-engineered T cells (TCR-T) could be advantageous in glioblastoma by allowing safe and ubiquitous targeting of the glioblastoma-derived peptidome. Protein tyrosine phosphatase receptor type Z1 (PTPRZ1), is a clinically targetable glioblastoma antigen associated with glioblastoma cell stemness. Here, we identify a therapeutic HLA-A*02-restricted PTPRZ1-reactive TCR retrieved from a vaccinated glioblastoma patient. Single-cell sequencing of primary brain tumors shows PTPRZ1 overexpression in malignant cells, especially in glioblastoma stem cells (GSCs) and astrocyte-like cells. The validated vaccine-induced TCR recognizes the endogenously processed antigen without off-target cross-reactivity. PTPRZ1-specific TCR-T (PTPRZ1-TCR-T) kill target cells antigen-specifically, and in murine experimental brain tumors, their combined intravenous and intracerebroventricular administration is efficacious. PTPRZ1-TCR-T maintain stem cell memory phenotype in vitro and in vivo and lyse all examined HLA-A*02+ primary glioblastoma cell lines with a preference for GSCs and astrocyte-like cells. In summary, we demonstrate the proof of principle to employ TCR-T to treat glioblastoma.

Clinical and biomarker analyses of SHR-1701 combined with famitinib in patients with previously treated advanced biliary tract cancer or pancreatic ductal adenocarcinoma: a phase II trial

Advanced biliary tract cancer (BTC) and pancreatic ductal adenocarcinoma (PDAC) have poor prognoses and limited treatment options. Here, we conducted this first-in-class phase II study to evaluate the efficacy and safety of SHR-1701, a bifunctional fusion protein targeting programmed death-ligand 1 (PD-L1) and transforming growth factor-beta (TGF-β), combined with famitinib, a multi-targeted receptor tyrosine kinase inhibitor, in patients with advanced BTC or PDAC who failed previous standard treatment (trial registration: ChiCTR2000037927). Among 51 enrolled patients, the BTC cohort showed an objective response rate (ORR) of 28% (including 2 complete responses) and a disease control rate (DCR) of 80%, with a median progression-free survival (mPFS) of 5.1 months and a median overall survival (mOS) of 16.0 months. In the PDAC cohort, the ORR was 15% (2 complete responses), with a DCR of 60%, and the mPFS and mOS were 2.1 months and 5.3 months, respectively. Grade 3 or 4 treatment-related adverse events (TRAEs) occurred in 29.4% of patients, with no grade 5 TRAEs reported. Exploratory analyses revealed that primary tumor resection history, peripheral blood immunophenotype changes, and distinct immune-metabolic profiles were associated with treatment benefits. An immune/metabolism score integrating the features of six genes was developed as a predictive biomarker for immunotherapy response in multiple cohorts, allowing for the selection of patients most likely to experience positive outcomes from this therapy regimen. In conclusion, our study provides proof-of-concept data supporting the potential of SHR-1701 plus famitinib as an effective and safe subsequent-line therapy for refractory BTC and PDAC, highlighting the promise of targeting PD-L1, TGF-β, and angiogenesis pathways simultaneously.

Interleukin-2-secreting T helper cells promote extra-follicular B cell maturation via intrinsic regulation of a B cell mTOR-AKT-Blimp-1 axis

During antigen-driven responses, B cells can differentiate at extra-follicular (EF) sites or initiate germinal centers (GCs) in processes that involve interactions with T cells. Here, we examined the roles of interleukin (IL)-2 secreted by T helper (Th) cells during cognate interactions with activated B cells. IL-2 boosted the expansion of EF plasma cells and the secretion of low-mutated immunoglobulin G (IgG). Conversely, genetically disrupting IL-2 expression by CD4+ T cells, or IL-2 receptor (CD25) expression by B cells, promoted B cell entry into the GC and high-affinity antibody secretion. Mechanistically, IL-2 induced early mTOR activity, expression of the transcriptional regulator IRF4, and metabolic changes in B cells required to form Blimp-1-expressing plasma cells. Thus, T cell help via IL-2 regulates an mTOR-AKT-Blimp-1 axis in activated B cells, providing insight into the mechanisms that determine EF versus GC fates and positioning IL-2 as an early switch controlling plasma cell versus GC B cell commitment.

The immune response behind peptide vaccination in diffuse midline glioma

A first-in-human trial demonstrated that a vaccine targeting the histone mutation H3K27M can induce an immune response, in a mutation-specific manner, in patients with diffuse midline glioma. In a recent study by Boschert et al., the same group now dissects the functional immune response triggered after effective vaccination of one of the patients, who has been in remission for over 3 years. The H3K27M peptide vaccine, named H3-vac, induces a CD4+ T-cell-specific immune response in this patient and expands the repertoire of polyclonal H3K27M-specific T-cell receptors. A clonal H3K27M-reactive B-cell population was also detected in the patient's cerebrospinal fluid. Importantly, the immune response is induced across various human leukocyte antigen alleleotypes, indicating the potential efficacy of the vaccine in diverse populations. By exploring in detail the immune response linked to this patient's long-term survival, the authors prove peptide vaccinations as a viable therapeutic approach. This paves the way for personalised therapies harnessing immunogenic T- and B-cell responses against different tumour types.

Cerebrospinal Fluid cfDNA Sequencing for Classification of Central Nervous System Glioma

PURPOSE

Primary central nervous system (CNS) gliomas can be classified by characteristic genetic alterations. In addition to solid tissue obtained via surgery or biopsy, cell-free DNA (cfDNA) from cerebrospinal fluid (CSF) is an alternative source of material for genomic analyses.

EXPERIMENTAL DESIGN

We performed targeted next-generation sequencing of CSF cfDNA in a representative cohort of 85 patients presenting at two neurooncological centers with suspicion of primary or recurrent glioma. Copy-number variation (CNV) profiles, single-nucleotide variants (SNV), and small insertions/deletions (indel) were combined into a molecular-guided tumor classification. Comparison with the solid tumor was performed for 38 cases with matching solid tissue available.

RESULTS

Cases were stratified into four groups: glioblastoma (n = 32), other glioma (n = 19), nonmalignant (n = 17), and nondiagnostic (n = 17). We introduced a molecular-guided tumor classification, which enabled identification of tumor entities and/or cancer-specific alterations in 75.0% (n = 24) of glioblastoma and 52.6% (n = 10) of other glioma cases. The overlap between CSF and matching solid tissue was highest for CNVs (26%-48%) and SNVs at predefined gene loci (44%), followed by SNVs/indels identified via uninformed variant calling (8%-14%). A molecular-guided tumor classification was possible for 23.5% (n = 4) of nondiagnostic cases.

CONCLUSIONS

We developed a targeted sequencing workflow for CSF cfDNA as well as a strategy for interpretation and reporting of sequencing results based on a molecular-guided tumor classification in glioma. See related commentary by Abdullah, p. 2860.

T-FINDER: A highly sensitive, pan-HLA platform for functional T cell receptor and ligand discovery

Effective, unbiased, high-throughput methods to functionally identify both class II and class I HLA-presented T cell epitopes and their cognate T cell receptors (TCRs) are essential for and prerequisite to diagnostic and therapeutic applications, yet remain underdeveloped. Here, we present T-FINDER [T cell Functional Identification and (Neo)-antigen Discovery of Epitopes and Receptors], a system to rapidly deconvolute CD4 and CD8 TCRs and targets physiologically processed and presented by an individual's unmanipulated, complete human leukocyte antigen (HLA) haplotype. Combining a highly sensitive TCR signaling reporter with an antigen processing system to overcome previously undescribed limitations to target expression, T-FINDER both robustly identifies unknown peptide:HLA ligands from antigen libraries and rapidly screens and functionally validates the specificity of large TCR libraries against known or predicted targets. To demonstrate its capabilities, we apply the platform to multiple TCR-based applications, including diffuse midline glioma, celiac disease, and rheumatoid arthritis, providing unique biological insights and showcasing T-FINDER's potency and versatility.