IL15 and IL21: Better When Membrane-Tethered Together on Antitumor T Cells

Systemic administration of homeostatic γ-chain cytokines mediates antitumor responses in some patients treated with adoptive immunotherapy. Yet many patients experience toxic side effects. New work presented herein suggests these limitations can be overcome by membrane-tethering IL15 and IL21 to T-cell products. This finding has major implications in advancing medicine. See related article by Nguyen et al., p. 1555.

Improving head and neck cancer therapies by immunomodulation of the tumour microenvironment

Targeted immunotherapy has improved patient survival in head and neck squamous cell carcinoma (HNSCC), but less than 20% of patients produce a durable response to these treatments. Thus, new immunotherapies that consider all key players of the complex HNSCC tumour microenvironment (TME) are necessary to further enhance tumour-specific T cell responses in patients. HNSCC is an ideal tumour type in which to evaluate immune and non-immune cell differences because of two distinct TME aetiologies (human papillomavirus (HPV)-positive and HPV-negative disease), multiple anatomic sites for tumour growth, and clear distinctions between patients with locally advanced disease and those with recurrent and/or metastatic disease. Recent technological and scientific advancements have provided a more complete picture of all cellular constituents within this complex TME and have evaluated the interplay of both immune and non-immune cells within HNSCC. Here, we include a comprehensive analysis of the complete ecosystem of the HNSCC TME, performed utilizing data-rich resources such as The Cancer Genome Atlas, and cutting-edge techniques, such as single-cell RNA sequencing, high-dimensional flow cytometry and spatial multispectral imaging, to generate improved treatment strategies for this diverse disease.

Phase I Trial of Cetuximab, Radiotherapy, and Ipilimumab in Locally Advanced Head and Neck Cancer

PURPOSE

Concurrent radiotherapy with cetuximab, an anti-EGFR mAb, is a standard treatment for locally advanced head and neck squamous carcinoma (HNSCC). Cytotoxic T lymphocyte antigen-4-positive (CTLA-4+) regulatory T cells (Treg) dampen cellular immunity and correlate negatively with clinical outcomes. This phase I study added ipilimumab, an anti-CTLA-4 mAb, to cetuximab-radiotherapy.

PATIENTS AND METHODS

A (3 + 3) design was used to establish the recommended phase II dose (RP2D) of ipilimumab, added at week 5 for four, every-3-week doses to fixed, standard cetuximab-radiotherapy. Eligible subjects had stage III to IVb, high-risk [human papillomavirus-negative (HPV-)] or intermediate-risk HPV-positive (HPV+)] HNSCC. Dose-limiting toxicity (DLT) was defined as any grade 4 adverse event (AE) except in-field radiation dermatitis or immune-related (ir) AE requiring ≥2 weeks of systemic steroids. Baseline tumor and serial blood specimens were collected for immune correlatives.

RESULTS

From July 2013 to May 2016, 18 patients enrolled. Two of 6 in cohort 1 (ipilimumab 3 mg/kg) experienced grade 3 dermatologic DLTs, triggering deescalation of ipilimumab to 1 mg/kg. Dose level -1 was expanded to N  =  12 without DLT. irAE included: grade 1, 2, and 3 dermatitis (2, 1, and 3 cases), grade 4 colitis (1), and grade 1 hyperthyroidism (1). Three-year disease-free survival (DFS) and overall survival were 72% [90% confidence interval (CI), 57-92] and 72% (90% CI, 56-92). High expression of coinhibitory receptors PD1/LAG3/CD39 on baseline tumor-infiltrating Treg was associated with worse DFS (HR = 5.6; 95% CI, 0.83-37.8; P = 0.08).

CONCLUSIONS

The RP2D for ipilimumab plus standard cetuximab-radiotherapy is 1 mg/kg in weeks 5, 8, 11, and 14. The regimen is tolerable and yields acceptable survival without cytotoxic chemotherapy.

People critically ill with COVID-19 exhibit peripheral immune profiles predictive of mortality and reflective of SARS-CoV-2 lung viral burden

Despite extensive analyses, there remains an urgent need to delineate immune cell states that contribute to mortality in people critically ill with COVID-19. Here, we present high-dimensional profiling of blood and respiratory samples from people with severe COVID-19 to examine the association between cell-linked molecular features and mortality outcomes. Peripheral transcriptional profiles by single-cell RNA sequencing (RNA-seq)-based deconvolution of immune states are associated with COVID-19 mortality. Further, persistently high levels of an interferon signaling module in monocytes over time lead to subsequent concerted upregulation of inflammatory cytokines. SARS-CoV-2-infected myeloid cells in the lower respiratory tract upregulate CXCL10, leading to a higher risk of death. Our analysis suggests a pivotal role for viral-infected myeloid cells and protracted interferon signaling in severe COVID-19.

B cell signatures and tertiary lymphoid structures contribute to outcome in head and neck squamous cell carcinoma

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.

Abstract PR06: Tumor-infiltrating B cells colocalize with CD4 T effector cells within tertiary lymphoid structures to present antigen and educate the antitumor immune response in human primary tumors

Despite the success of checkpoint blockade immunotherapies, i.e., anti-PD1, only 20% of patients produce a durable response to these treatments. Thus, a need exists to develop additional therapeutic strategies to treat these patients, which includes evaluation of other tumor-infiltrating immune cells that could further augment the CD8+ and CD4+ T-cell response. Tumor-infiltrating B cells (TIL-B) represent a possible target for immunotherapy due to their predominance in the tumor microenvironment and crucial role in the immune response. In fact, current evidence suggests an antitumor role for TIL-Bs. Specifically, detection of TIL-Bs within tertiary lymphoid structures (TLS) correlates with both increased survival in patients with solid tumors and enhanced response to anti-PD1 immunotherapy. We hypothesize that TIL-Bs help generate potent, long-term immune responses against cancer by presenting tumor antigens to CD4 TILs within TLS. Utilizing single-cell RNAseq and high-level flow cytometry, we observed increased numbers of activated TIL-Bs in the primary tumors of head and neck squamous cell carcinoma (HNSCC) and non-small cell lung cancer (NSCLC) patients. We further assessed the location of TIL-Bs within the TME and determined that they predominantly sit adjacent to CD4+ tumor-infiltrating lymphocytes (TILs) within TLS. Thus, we generated an antigen presentation assay in vitro, and we observed increased CD4+ TIL responses when TIL-Bs presented autologous tumor antigens. Further, there was a differential impact on CD4+ TIL phenotype; specifically, if TIL-Bs were activated (CD27+), the CD4+ TILs were T helper (anti-tumor) CD4+ T cells and if the TIL-Bs were nonactivated (CD27-), the CD4+ TILs were T regulatory cells (protumor). These data suggest that TIL-Bs influence the phenotype and function of CD4+ TILs in patient tumors within TLS. Ultimately, results from this study will increase effective targeting of TIL-Bs within patient primary tumors.

Citation Format: Ayana T. Ruffin, Anthony R. Cillo, Sheryl Kunning, Robert L. Ferris, Dario A.A. Vignali, Tullia C. Bruno. Tumor-infiltrating B cells colocalize with CD4 T effector cells within tertiary lymphoid structures to present antigen and educate the antitumor immune response in human primary tumors [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr PR06.

Distinct B cell signatures and tertiary lymphoid structures are driven by two etiol-ogies in head and neck cancer

B cells can regulate immune responses by presenting antigen, producing antigen-specific antibodies and immunomodulatory cytokines. Their role in the anti-tumor immune response is poorly understood. However, in many cancers including head and neck squamous cell carcinoma (HNSCC), intratumoral B cells correlate with better survival. HNSCC has two distinct etiologies (HPV−) and (HPV+) where patients who are HPV+ have increased B cell infiltration and respond better to therapy. We hypothesized that (1) intratumoral B cell phenotype is different between HPV+ and HPV− HNSCC (2) location within the tumor microenvironment (TME) is distinct and (3) antibodies produced by intratumoral B cell in HPV+ HNSCC are specific for viral antigens.

Using single-cell RNA sequencing and spectral flow cytometry, we observed that B cell signatures in HPV− HNSCC patients were predominantly memory B cells and plasma cells, while the signatures in HPV+ HNSCC were naïve and germinal center (GC) B cells. Further, we quantified B cells in tertiary lymphoid structures (TLS) using multispectral immunofluorescence, and the presence of GC-rich TLS were increased in HPV+ patients. In fact, GC-rich TLS within the tumor of HPV+ patients correlated with increased overall survival. Overall, high enrichment for GC B cells were positively associated with longer progression-free survival. Antibodies produced by intratumoral B cells from HPV+ patients were positive for HPV viral antigens. Ultimately, characterization of B cell phenotype and function in HNSCC is important for devising new therapeutic options for cancer patients. Specifically, therapeutics to enhance B cell responses in the TME should be prioritized as a compliment to T-cell mediated therapies.

Abstract A053: Activated B cells in human primary tumors present antigen and increase antitumor function of CD4 T-cells in tertiary lymphoid structures

Immunotherapy, specifically anti-PD1, has improved patient survival in a range of tumor types including head and neck squamous cell carcinoma (HNSCC) and non-small cell lung cancer (NSCLC). Despite the success of anti-PD1 therapy, only 20% of patients produce a durable response to this treatment. Thus, a need exists to develop additional therapeutic strategies to treat these patients, which includes evaluation of other tumor-infiltrating immune cells that could further augment the CD8+ and CD4+ T-cell response. Tumor-infiltrating B cells (TIL-B) represent a possible target for immunotherapy due to their predominance in the tumor microenvironment (TME) and crucial role in the immune response. However, TIL-B function in cancer and in the context of immunotherapy has been understudied. In fact, conclusions on an anti- or protumor role for TIL-Bs in the TME is dependent on the study. However, in HNSCC and NSCLC patients, current evidence suggests an antitumor role for TIL-Bs. Specifically, detection of TIL-Bs within tertiary lymphoid structures (TLS) correlates with better prognosis. While TIL-Bs have been identified in HNSCC and NSCLC patients, their complete phenotypic signature and function in the TME has been understudied with no focus on their role as antigen presenting cells (APCs) and their influence on CD8+ and CD4+ tumor infiltrating lymphocytes (TILs). We hypothesize that TIL-Bs help generate potent, long-term immune responses against cancer by presenting tumor antigens to CD4 TILs within TLS.Using unmanipulated, primary human B cells from fresh tumor, we quantified and further characterized TIL-Bs in HNSCC and NSCLC utilizing single-cell RNAseq and multiparameter flow cytometry. We observed increased numbers of activated TIL-Bs in these primary tumors compared to other immune subsets, specifically CD27+ TIL-Bs. We further assessed the TIL-Bs by correlating phenotype of the TIL-B with its location in the TME, predominantly separating out differences between TIL-Bs within TLS and outside TLS. In addition, we generated a specific antigen presentation assay in vitro, and we observed three types of CD4+ TIL responses when TIL-Bs presented autologous tumor antigens. There were activated responder CD4+ TILs that proliferated when combined with TIL-Bs alone, which indicates stimulation with endogenous tumor antigens. There were antigen-associated responders that required exogenous autologous tumor lysate to elicit a CD4+ TIL response, and there were patient CD4 TILs that did not respond to antigen presentation by TIL-Bs. Within the activated and antigen-associated responders, the TIL-B phenotype influenced the CD4+ TIL phenotype; if the TIL-Bs were activated (CD27+), the CD4+ TILs were T helper (antitumor) CD4+ T-cells and if the TIL-Bs were non-activated (CD27-), the CD4+ TILs were T regulatory cells (protumor). These data suggest that TIL-Bs influence the phenotype and function of CD4+ TILs in patient tumors. In conclusion, activated TIL-Bs are increased in human primary tumors, they can present antigen to CD4+ TILs and influence their overall phenotype. Determining the complete activation signature of TIL-Bs in HNSCC and NSCLC patients will determine the extent of their antitumor function in these cancers. Comparison of TIL-Bs in HNSCC and NSCLC is important as there are not many unified studies on TIL-B function across tumor types. Further, because HNSCC has two etiologies (viral vs. carcinogen induced), we are able to better study the differential function of activated and nonactivated TIL-Bs in solid tumors. Ultimately, results from this study will help predict how to target TIL-B functions in future TIL-B-specific immunotherapies or in combination with current immunotherapies for HNSCC and NSCLC patients like blockade of the inhibitory receptor, PD-1.

Citation Format: Tullia C. Bruno, Ayana T. Ruffin, Anthony R. Cillo, Robert L. Ferris, Dario A.A. Vignali. Activated B cells in human primary tumors present antigen and increase antitumor function of CD4 T-cells in tertiary lymphoid structures [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A053.