Head and neck squamous cell carcinoma (HNSCC) arises through exposure to environmental carcinogens or malignant transformation by human papillomavirus (HPV). Here, we assessed the transcriptional ...profiles of 131,224 single cells from peripheral and intra-tumoral immune populations from patients with HPV– and HPV+ HNSCC and healthy donors. Immune cells within tumors of HPV– and HPV+ HNSCC displayed a spectrum of transcriptional signatures, with helper CD4+ T cells and B cells being relatively divergent and CD8+ T cells and CD4+ regulatory T cells being relatively similar. Transcriptional results were contextualized through multispectral immunofluorescence analyses and evaluating putative cell-cell communication based on spatial proximity. These analyses defined a gene expression signature associated with CD4+ T follicular helper cells that is associated with longer progression-free survival in HNSCC patients. The datasets and analytical approaches herein provide a resource for the further study of the impact of immune cells on viral- and carcinogen-induced cancers.
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•Single-cell RNA-seq revealed distinct immune profiles in HPV– and HPV+ HNSCC•B cells, myeloid cells, and CD4+ Tconv cells were divergent by high-dimensional analysis•Multispectral imaging uncovered immune structures (TLSs) associated with HPV+ disease•T follicular helper signature was associated with favorable survival in TCGA patients
Head and neck squamous cell carcinoma (HNSCC) arises through exposure to environmental carcinogens or human papillomavirus (HPV). Cillo et al. determine single-cell transcriptional profiles of peripheral and intra-tumoral immune populations from patients with HPV– and HPV+ HNSCC and healthy donors. These datasets, accompanied by spatial organization information, provide a resource for further study of immunity to viral- and carcinogen-induced cancers.
Current immunotherapy paradigms aim to reinvigorate CD8
T cells, but the contribution of humoral immunity to antitumor immunity remains understudied. Here, we demonstrate that in head and neck ...squamous cell carcinoma (HNSCC) caused by human papillomavirus infection (HPV
), patients have transcriptional signatures of germinal center (GC) tumor infiltrating B cells (TIL-Bs) and spatial organization of immune cells consistent with tertiary lymphoid structures (TLS) with GCs, both of which correlate with favorable outcome. GC TIL-Bs in HPV
HNSCC are characterized by distinct waves of gene expression consistent with dark zone, light zone and a transitional state of GC B cells. Semaphorin 4a expression is enhanced on GC TIL-Bs present in TLS of HPV
HNSCC and during the differentiation of TIL-Bs. Our study suggests that therapeutics to enhance TIL-B responses in HNSCC should be prioritized in future studies to determine if they can complement current T cell mediated immunotherapies.
Reversal of proviral latency is being pursued as a curative strategy for HIV-1 infection. Recent clinical studies of in vivo administration of the histone deacetylase inhibitor suberoylanilide ...hydroxamic acid (SAHA; vorinostat) show increases in unspliced cellular HIV-1 RNA levels in resting CD4 ⁺ T cells. A critical unknown, however, is the proportion of latent proviruses that can be transcriptionally reactivated by SAHA or T-cell activation. In this study, we quantified the fraction of HIV-1 proviruses in resting CD4 ⁺ T cells from patients on suppressive antiretroviral therapy that were reactivated ex vivo with SAHA or antibodies to CD3/CD28. At concentrations of SAHA achieved clinically, only 0.079% of proviruses in resting CD4 ⁺ T cells were reactivated to produce virions, compared with 1.5% of proviruses in cells treated with anti-CD3/CD28 antibodies after correcting for spontaneous virion production in the medium control. A significant positive correlation (ρ = 0.67, P < 0.001) was found between levels of virions in the supernatant and unspliced cellular HIV-1 RNA following anti-CD3/CD28 treatment, but not following SAHA treatment (ρ = 0.21, P = 0.99). These results reveal that the majority of HIV-1 proviruses are not reactivated by current therapeutic approaches and that more effective means of reversing proviral latency will likely be required to deplete HIV-1 reservoirs.
The composition of the intestinal microbiota is associated with both the development of tumors and the efficacy of anti-tumor immunity. Here, we examined the impact of microbiota-specific T cells in ...anti-colorectal cancer (CRC) immunity. Introduction of Helicobacter hepaticus (Hhep) in a mouse model of CRC did not alter the microbial landscape but increased tumor infiltration by cytotoxic lymphocytes and inhibited tumor growth. Anti-tumor immunity was independent of CD8+ T cells but dependent upon CD4+ T cells, B cells, and natural killer (NK) cells. Hhep colonization induced Hhep-specific T follicular helper (Tfh) cells, increased the number of colon Tfh cells, and supported the maturation of Hhep+ tumor-adjacent tertiary lymphoid structures. Tfh cells were necessary for Hhep-mediated tumor control and immune infiltration, and adoptive transfer of Hhep-specific CD4+ T cells to Tfh cell-deficient Bcl6fl/flCd4Cre mice restored anti-tumor immunity. Thus, introduction of immunogenic intestinal bacteria can promote Tfh-associated anti-tumor immunity in the colon, suggesting therapeutic approaches for the treatment of CRC.
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•Helicobacter hepaticus (Hhep) colonization reduces colorectal cancer burden in mice•Hhep induces CD4+ Tfh cell- and B cell-dependent anti-colorectal cancer immunity•Hhep colonization expands peritumoral tertiary lymphoid structures (TLSs)•Hhep-specific Tfh cells promote both TLSs and anti-tumor immunity
The effectiveness of immune-mediated cancer therapy is modulated by the microbiota. Overacre-Delgoffe et al. reveal that colonization of colon tumor-bearing mice with an immunogenic intestinal bacteria, Helicobacter hepaticus, induces Hhep-specific T follicular helper cells and tumor-adjacent lymphoid structures, thereby promoting anti-tumor immunity.
Little is known about the fraction of human immunodeficiency virus type 1 (HIV-1) proviruses that express unspliced viral RNA in vivo or about the levels of HIV RNA expression within single infected ...cells. We developed a sensitive cell-associated HIV RNA and DNA single-genome sequencing (CARD-SGS) method to investigate fractional proviral expression of HIV RNA (1.3-kb fragment of p6, protease, and reverse transcriptase) and the levels of HIV RNA in single HIV-infected cells from blood samples obtained from individuals with viremia or individuals on long-term suppressive antiretroviral therapy (ART). Spiking experiments show that the CARD-SGS method can detect a single cell expressing HIV RNA. Applying CARD-SGS to blood mononuclear cells in six samples from four HIV-infected donors (one with viremia and not on ART and three with viremia suppressed on ART) revealed that an average of 7% of proviruses (range: 2–18%) expressed HIV RNA. Levels of expression varied from one to 62 HIV RNA molecules per cell (median of 1). CARD-SGS also revealed the frequent expression of identical HIV RNA sequences across multiple single cells and across multiple time points in donors on suppressive ART consistent with constitutive expression of HIV RNA in infected cell clones. Defective proviruses were found to express HIV RNA at levels similar to those proviruses that had no obvious defects. CARD-SGS is a useful tool to characterize fractional proviral expression in single infected cells that persist despite ART and to assess the impact of experimental interventions on proviral populations and their expression.
Immunotherapy targeting coinhibitory receptors has been highly successful in treating a wide variety of malignancies; however, only a subset of patients exhibits durable responses. The first ...FDA-approved immunotherapeutics targeting coinhibitory receptors PD1 and CTLA4, alone or in combination, significantly improved survival but were also accompanied by substantial toxicity in combination. The third FDA-approved immune checkpoint inhibitor targets LAG3, a coinhibitory receptor expressed on activated CD4+ and CD8+ T cells, especially in settings of long-term antigenic stimulation, such as chronic viral infection or cancer. Mechanistically, LAG3 expression limits both the expansion of activated T cells and the size of the memory pool, suggesting that LAG3 may be a promising target for immunotherapy. Importantly, the mechanism(s) by which LAG3 contributes to CD8+ T-cell exhaustion may be distinct from those governed by PD1, indicating that the combination of anti-LAG3 and anti-PD1 may synergistically enhance antitumor immunity. Clinical studies evaluating the role of anti-LAG3 in combination with anti-PD1 are underway, and recent phase III trial results in metastatic melanoma demonstrate both the efficacy and safety of this combination. Further ongoing clinical trials are evaluating this combination across multiple tumor types and the adjuvant setting, with accompanying translational and biomarker-focused studies designed to elucidate the molecular pathways that lead to improved antitumor T-cell responses following dual blockade of PD1 and LAG3. Overall, LAG3 plays an important role in limiting T-cell activation and has now become part of the repertoire of combinatorial immunotherapeutics available for the treatment of metastatic melanoma.
Head and neck squamous cell carcinoma (HNSCC) is characterized by complex relations between stromal, epithelial, and immune cells within the tumor microenvironment (TME). To enable the development of ...more efficacious therapies, we aim to study the heterogeneity, signatures of unique cell populations, and cell-cell interactions of non-immune and immune cell populations in 6 human papillomavirus (HPV)
and 12 HPV
HNSCC patient tumor and matched peripheral blood specimens using single-cell RNA sequencing. Using this dataset of 134,606 cells, we show cell type-specific signatures associated with inflammation and HPV status, describe the negative prognostic value of fibroblasts with elastic differentiation specifically in the HPV
TME, predict therapeutically targetable checkpoint receptor-ligand interactions, and show that tumor-associated macrophages are dominant contributors of PD-L1 and other immune checkpoint ligands in the TME. We present a comprehensive single-cell view of cell-intrinsic mechanisms and cell-cell communication shaping the HNSCC microenvironment.
Although a number of PCR-based quantitative assays for measuring HIV-1 persistence during suppressive antiretroviral therapy (ART) have been reported, a simple, sensitive, reproducible method is ...needed for application to large clinical trials. We developed novel quantitative PCR assays for cell-associated (CA) HIV-1 DNA and RNA, targeting a highly conserved region in HIV-1pol, with sensitivities of 3 to 5 copies/1 million cells. We evaluated the performance characteristics of the assays using peripheral blood mononuclear cells (PBMCs) from 5 viremic patients and 20 patients receiving effective ART. Total and resting CD4(+)T cells were isolated from a subset of patients and tested for comparison with PBMCs. The estimated standard deviations including interassay variability and intra-assay variability of the assays were modest, i.e., 0.15 and 0.10 log10copies/10(6)PBMCs, respectively, for CA HIV-1 DNA and 0.40 and 0.19 log10copies/10(6)PBMCs for CA HIV-1 RNA. Testing of longitudinally obtained PBMC samples showed little variation for either viremic patients (median fold differences of 0.80 and 0.88 for CA HIV-1 DNA and RNA, respectively) or virologically suppressed patients (median fold differences of 1.14 and 0.97, respectively). CA HIV-1 DNA and RNA levels were strongly correlated (r= 0.77 to 1;P= 0.0001 to 0.037) for assays performed using PBMCs from different sources (phlebotomy versus leukapheresis) or using total or resting CD4(+)T cells purified by either bead selection or flow cytometric sorting. Their sensitivity, reproducibility, and broad applicability to small numbers of mononuclear cells make these assays useful for observational and interventional studies that examine longitudinal changes in the numbers of HIV-1-infected cells and their levels of transcription.
•Eradication, functional, and hybrid cures for HIV-1 are under investigation.•‘Kick and kill’ has been the most intensively studied curative strategy to date.•HIV-1 latency reversing agents have ...increased cellular HIV-1 RNA in vivo.•Whether latency reversing agents are safe and can deplete the reservoir is unknown.•Boosting immunologic control of HIV-1 should be pursued as part of a hybrid cure.
Strategies to achieve a cure for HIV-1 infection can be broadly classified into three categories: eradication cure (elimination of all viral reservoirs), functional cure (immune control without reservoir eradication), or a hybrid cure (reservoir reduction with improved immune control). The many HIV-1 cure strategies being investigated include modification of host cells to resist HIV-1, engineered T cells to eliminate HIV-infected cells, broadly HIV-1 neutralizing monoclonal antibodies, and therapeutic vaccination, but the ‘kick and kill’ strategy to expose latent HIV-1 with latency reversing agents (LRAs) and kill the exposed cells through immune effector functions is currently the most actively pursued. It is unknown, however, whether LRAs can deplete viral reservoirs in vivo or whether current LRAs are sufficiently safe for clinical use.
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