Combination immunotherapy with synthetic long peptides and chemotherapy or PD-1 blocker for cancers caused by human papilloma virus type 16

Therapeutic vaccination of premalignant conditions and of different stages of cancer can be accomplished with several platforms including DNA vaccines, RNA vaccines, synthetic long peptides (SLP), and recombinant viruses. We successfully used a therapeutic vaccine composed of SLP covering the complete sequence of the two oncogenic proteins E6 and E7 of human papillomavirus type 16 (HPV16) as monotherapy in patients with premalignant disease. However, combination treatment might be required in patients with (advanced) cancer because of the hostile cancer microenvironment for T cells in established HPV16+ cancer, often associated with systemic immunosuppression. In patients with late-stage recurrent or metastatic HPV16+ cancers, we have therefore combined treatment with the SLP vaccine, called ISA101b, with either standard-of-care chemotherapy or with immune checkpoint inhibition with anti-PD-1 monoclonal antibody. A strong vaccine-induced interferon gamma-producing T cell response to HPV16 E6/E7 was associated with significantly better survival. In a second phase 1/2 study, patients with recurrent or metastatic HPV16+ oropharyngeal cancer were treated with the combination of ISA101b and anti-PD-1 (nivolumab). In this trial, the clinical overall response rate (ORR) in 22 patients was 36%, twice the ORR in the nivolumab registration trial for this category of patients, and 2/22 patients had a complete clinical response that is ongoing after 4 1/2 years. Other promising strategies for late-stage cancer recipients are the infusion of expanded tumor-infiltrating lymphocytes or the infusion of T cell receptor transduced T cells, both directed against HPV16.

Metabolic activation and colitis pathogenesis is prevented by lymphotoxin β receptor expression in neutrophils

Inflammatory bowel disease is characterized by an exacerbated intestinal immune response, but the critical mechanisms regulating immune activation remain incompletely understood. We previously reported that the TNF-superfamily molecule TNFSF14 (LIGHT) is required for preventing severe disease in mouse models of colitis. In addition, deletion of lymphotoxin beta receptor (LTβR), which binds LIGHT, also led to aggravated colitis pathogenesis. Here, we aimed to determine the cell type(s) requiring LTβR and the mechanism critical for exacerbation of colitis. Specific deletion of LTβR in neutrophils (LTβRΔN), but not in several other cell types, was sufficient to induce aggravated colitis and colonic neutrophil accumulation. Mechanistically, RNA-Seq analysis revealed LIGHT-induced suppression of cellular metabolism, and mitochondrial function, that was dependent on LTβR. Functional studies confirmed increased mitochondrial mass and activity, associated with excessive mitochondrial ROS production and elevated glycolysis at steady-state and during colitis. Targeting these metabolic changes rescued exacerbated disease severity. Our results demonstrate that LIGHT signals to LTβR on neutrophils to suppress metabolic activation and thereby prevents exacerbated immune pathogenesis during colitis.

PD-L1 blockade engages tumor-infiltrating lymphocytes to co-express targetable activating and inhibitory receptors

BACKGROUND

The clinical benefit of immunotherapeutic approaches against cancer has been well established although complete responses are only observed in a minority of patients. Combination immunotherapy offers an attractive avenue to develop more effective cancer therapies by improving the efficacy and duration of the tumor-specific T-cell response. Here, we aimed at deciphering the mechanisms governing the response to PD-1/PD-L1 checkpoint blockade to support the rational design of combination immunotherapy.

METHODS

Mice bearing subcutaneous MC-38 tumors were treated with blocking PD-L1 antibodies. To establish high-dimensional immune signatures of immunotherapy-specific responses, the tumor microenvironment was analyzed by CyTOF mass cytometry using 38 cellular markers. Findings were further examined and validated by flow cytometry and by functional in vivo experiments. Immune profiling was extended to the tumor microenvironment of colorectal cancer patients.

RESULTS

PD-L1 blockade induced selectively the expansion of tumor-infiltrating CD4+ and CD8+ T-cell subsets, co-expressing both activating (ICOS) and inhibitory (LAG-3, PD-1) molecules. By therapeutically co-targeting these molecules on the TAI cell subsets in vivo by agonistic and antagonist antibodies, we were able to enhance PD-L1 blockade therapy as evidenced by an increased number of TAI cells within the tumor micro-environment and improved tumor protection. Moreover, TAI cells were also found in the tumor-microenvironment of colorectal cancer patients.

CONCLUSIONS

This study shows the presence of T cell subsets in the tumor micro-environment expressing both activating and inhibitory receptors. These TAI cells can be targeted by combined immunotherapy leading to improved survival.

Lymphotoxin receptor beta expression by neutrophils is a critical regulator of colitis pathogenesis

Inflammatory bowel disease, while multifactorial, is largely characterized by an exacerbated intestinal immune activation. However, the critical mechanisms regulating immune activation remain to be fully defined. We have previously reported that a member of the TNF superfamily, TNFSF14/LIGHT, is required for prevention of severe disease in a mouse model of dextran sodium sulfate (DSS) induced colitis. Additionally, antibody-mediated blocking of lymphotoxin beta receptor (LTβR), which recognizes LIGHT, also led to exacerbated colitis pathogenesis. Thus, we aimed to determine the cell type(s) and mechanism critical to LTβR mediated exacerbation of DSS driven colitis. Employing the use of LTβRflox/flox mice and appropriate Cre strains, we were able to evaluate the role of LTβR signaling during DSS-induced colitis in a variety of immune and intestinal cell types. For all experiments, body weight, colon length and intestinal histopathology were assessed. These studies revealed that neutrophils were the critical LTβR expressing cell type and that specific deletion of neutrophil LTβR expression, via MRP8 Cre, resulted in exacerbated DSS-induced colitis similar to that in LIGHT−/− mice. RNASeq analysis of neutrophils revealed alterations in cellular metabolism and mitochondrial function, further confirmed through ex vivo analysis of LTβR deficient neutrophils, which had increased mitochondria. In sum, our results demonstrate that neutrophil LTβR activation, likely through LIGHT signaling, plays a critical role in the immune activation associated with DSS-induced colitis.