SARS-CoV-2 messenger RNA vaccination in healthy individuals generates immune protection against COVID-19. However, little is known about SARS-CoV-2 mRNA vaccine-induced responses in immunosuppressed ...patients. We investigated induction of antigen-specific antibody, B cell and T cell responses longitudinally in patients with multiple sclerosis (MS) on anti-CD20 antibody monotherapy (n = 20) compared with healthy controls (n = 10) after BNT162b2 or mRNA-1273 mRNA vaccination. Treatment with anti-CD20 monoclonal antibody (aCD20) significantly reduced spike-specific and receptor-binding domain (RBD)-specific antibody and memory B cell responses in most patients, an effect ameliorated with longer duration from last aCD20 treatment and extent of B cell reconstitution. By contrast, all patients with MS treated with aCD20 generated antigen-specific CD4 and CD8 T cell responses after vaccination. Treatment with aCD20 skewed responses, compromising circulating follicular helper T (T
) cell responses and augmenting CD8 T cell induction, while preserving type 1 helper T (T
1) cell priming. Patients with MS treated with aCD20 lacking anti-RBD IgG had the most severe defect in circulating T
responses and more robust CD8 T cell responses. These data define the nature of the SARS-CoV-2 vaccine-induced immune landscape in aCD20-treated patients and provide insights into coordinated mRNA vaccine-induced immune responses in humans. Our findings have implications for clinical decision-making and public health policy for immunosuppressed patients including those treated with aCD20.
Exhausted CD8 T cells (T
) are a distinct state of T cell differentiation associated with failure to clear chronic viruses and cancer. Immunotherapies such as PD-1 blockade can reinvigorate T
cells, ...but reinvigoration is not durable. A major unanswered question is whether T
cells differentiate into functional durable memory T cells (T
) upon antigen clearance. Here, using a mouse model, we found that upon eliminating chronic antigenic stimulation, T
cells partially (re)acquire phenotypic and transcriptional features of T
cells. These 'recovering' T
cells originated from the T cell factor (TCF-1
) T
progenitor subset. Nevertheless, the recall capacity of these recovering T
cells remained compromised as compared to T
cells. Chromatin-accessibility profiling revealed a failure to recover core memory epigenetic circuits and maintenance of a largely exhausted open chromatin landscape. Thus, despite some phenotypic and transcriptional recovery upon antigen clearance, exhaustion leaves durable epigenetic scars constraining future immune responses. These results support epigenetic remodeling interventions for T
cell-targeted immunotherapies.
Immunological tolerance has evolved to curtail immune responses against self-antigens and prevent autoimmunity. One mechanism that contributes to immunological tolerance is the expression of ...inhibitory receptors by lymphocytes that signal to dampen immune responses during the course of an infection and to prevent immune-mediated collateral damage to the host. The understanding that tumors exploit these physiological mechanisms to avoid elimination has led to remarkable, but limited, success in the treatment of cancer through the use of biologics that interfere with the ability of cancers to suppress immune function. This therapy, based on the understanding of how T lymphocytes are normally activated and suppressed, has led to the development of therapeutic blocking antibodies, referred to as immune checkpoint blockade, which either directly or indirectly promote the activation of CD8 T cells to eradicate cancer. Here, we highlight the distinct signaling mechanisms, timing and location of inhibition used by the CTLA-4 and PD-1 inhibitory receptors compared to a novel inhibitory signaling axis comprised of the bioactive lipid, lysophosphatidic acid (LPA), signaling via the LPA5 receptor expressed by CD8 T cells. Importantly, abundant evidence indicates that an LPA-LPA5 signaling axis is also exploited by diverse cancers to suppress T cell activation and function. Clearly, a thorough molecular and biochemical understanding of how diverse T cell inhibitory receptors signal to suppress T cell antigen receptor signaling and function will be important to inform the choice of which complimentary checkpoint blockade modalities might be used for a given cancer.
Persistent T cell antigen receptor (TCR) signaling by CD8 T cells is a feature of cancer and chronic infections and results in the sustained expression of, and signaling by, inhibitory receptors, ...which ultimately impair cytotoxic activity via poorly characterized mechanisms. We have previously determined that the LPA
5
GPCR expressed by CD8 T cells, upon engaging the lysophosphatidic acid (LPA) bioactive serum lipid, functions as an inhibitory receptor able to negatively regulate TCR signaling. Notably, the levels of LPA and autotaxin (ATX), the phospholipase D enzyme that produces LPA, are often increased in chronic inflammatory disorders such as chronic infections, autoimmune diseases, obesity, and cancer. In this report, we demonstrate that LPA engagement selectively by LPA
5
on human and mouse CD8 T cells leads to the inhibition of several early TCR signaling events including intracellular calcium mobilization and ERK activation. We further show that, as a consequence of LPA
5
suppression of TCR signaling, the exocytosis of perforin-containing granules is significantly impaired and reflected by repressed
in vitro
and
in vivo
CD8 T cell cytolytic activity. Thus, these data not only document LPA
5
as a novel inhibitory receptor but also determine the molecular and biochemical mechanisms by which a naturally occurring serum lipid that is elevated under settings of chronic inflammation signals to suppress CD8 T cell killing activity in both human and murine cells. As diverse tumors have repeatedly been shown to aberrantly produce LPA that acts in an autocrine manner to promote tumorigenesis, our findings further implicate LPA in activating a novel inhibitory receptor whose signaling may be therapeutically silenced to promote CD8 T cell immunity.
Abstract
Some risk factors for severe coronavirus disease 2019 (COVID-19) have been identified, including age, race, and obesity. However, 20%–50% of severe cases occur in the absence of these ...factors. Cytomegalovirus (CMV) is a herpesvirus that infects about 50% of all individuals worldwide and is among the most significant nongenetic determinants of immune system. We hypothesized that latent CMV infection might influence the severity of COVID-19. Our analyses demonstrate that CMV seropositivity is associated with more than twice the risk of hospitalization due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Immune profiling of blood and CMV DNA quantitative polymerase chain reaction in a subset of patients for whom respiratory tract samples were available revealed altered T-cell activation profiles in absence of extensive CMV replication in the upper respiratory tract. These data suggest a potential role for CMV-driven immune perturbations in affecting the outcome of SARS-CoV-2 infection and may have implications for the discrepancies in COVID-19 severity between different human populations.
Of severe cases of coronavirus disease 2019 (COVID-19), 20%–50% occur in the absence of identified factors. We demonstrated that cytomegalovirus seropositivity is associated with more than twice the risk of hospitalization due to COVID-19, possibly through systemic immune perturbation.
Persistent inflammation driven by cytokines such as type-one interferon (IFN-I) can cause immunosuppression. We show that administration of the Janus kinase 1 (JAK1) inhibitor itacitinib after ...anti–PD-1 (programmed cell death protein 1) immunotherapy improves immune function and antitumor responses in mice and results in high response rates (67%) in a phase 2 clinical trial for metastatic non–small cell lung cancer. Patients who failed to respond to initial anti–PD-1 immunotherapy but responded after addition of itacitinib had multiple features of poor immune function to anti–PD-1 alone that improved after JAK inhibition. Itacitinib promoted CD8 T cell plasticity and therapeutic responses of exhausted and effector memory–like T cell clonotypes. Patients with persistent inflammation refractory to itacitinib showed progressive CD8 T cell terminal differentiation and progressive disease. Thus, JAK inhibition may improve the efficacy of anti–PD-1 immunotherapy by pivoting T cell differentiation dynamics.
Editor’s summary Cancer immunotherapy is a type of treatment that mobilizes a patient’s immune system to kill tumor cells. It has been successful in treating certain tumors, but patients frequently have chronic inflammation and immunosuppression, which can limit treatment response. Two independent clinical trials looked at whether dialing down inflammation using drugs called JAK inhibitors could improve the efficacy of anti–PD-1 immunotherapy in cancer patients (see the Perspective by Gadina and O’Shea). Mathew et al . conducted a phase 2 trial to investigate the drug combination as a first-line therapy for metastatic non-small-cell lung cancer. Delayed administration of itacitinib after treatment with pembrolizumab improved therapeutic response. Zak et al . performed a phase 1/2 trial in patients with relapsed/refractory Hodgkin’s lymphoma. A combination of ruxolitinib and nivolumab resulted in improved clinical efficacy in patients who had previously failed checkpoint blockade immunotherapy. —Priscilla N. Kelly
INTRODUCTION Inflammation is a hallmark of cancer but is also required to generate optimal antitumor immune responses. Although short exposure to cytokines such as interferon (IFN) can enhance tumor immunity, prolonged exposure can result in immunosuppression. The dual nature of inflammation makes it challenging to harness the beneficial effects of cytokine activation during cancer immunotherapy while avoiding detrimental consequences. Thus, a therapeutical strategy to effectively modulate these often-opposing functions of cytokine signaling could improve immunotherapy efficacy and mitigate development of resistance. RATIONALE Preclinical studies in mice have demonstrated that blockade of type-one IFN (IFN-I) signaling can improve immune function during chronic viral infections and enhance the efficacy of immunotherapy for cancer. Moreover, tumors from patients with lung and other cancer types that relapse after—or are resistant to—immune checkpoint blockade (ICB) can have high expression of IFN-stimulated genes. Thus, we conducted a phase 2 clinical trial for first-line metastatic non–small cell lung cancer (NSCLC) with programmed death ligand 1 (PD-L1) expression ≥50%. Patients were administered 6 weeks of anti–PD-1 (PD-1, programmed cell death protein 1) immunotherapy, followed by a combination of anti–PD-1 and itacitinib a selective Janus kinase 1 (JAK1) inhibitor for 6 weeks before continuing with anti–PD-1 alone. To understand the immunological effects of transient JAK inhibition aimed at interfering with persistent inflammation occurring after anti–PD-1, we evaluated the association between clinical response and the evolution of CD8 T cell differentiation, immune signaling, and inflammatory markers. RESULTS In mice, the addition of itacitinib after the start of ICB improved response of interferon-stimulated gene (ISG)–high resistant tumors and increased the proportion of proliferating precursor-like CD8 T cells in the periphery. Use of an IFN-I–receptor blocking antibody similarly improved ICB efficacy, suggesting that blockade of IFN-I signaling is sufficient to phenocopy the effects of delayed JAK inhibition. In humans, the combination of anti–PD-1 with delayed, transient, itactinib treatment in patients with NSCLC led to an overall response rate of 67% and median progression-free survival of 23.8 months. Patients were categorized into three response groups based on the timing of radiographic response: patients with clinical response within the first two cycles of anti–PD-1 monotherapy (αPD1.R), patients who responded only after a 6-week course of concurrent itacitinib was added at the start of the third cycle of anti–PD-1 (JAKi.R), or patients who did not respond regardless of treatment (NR). Each clinical response group had distinctive immunological changes coupled to inflammatory features. The αPD1.R patients had low baseline inflammation and CD8 T cell responses after anti–PD-1 alone. JAKi.R patients had elevated inflammatory markers, poor CD8 T cell responses, and blunted immune signaling after anti–PD-1 alone. However, after addition of itacitinib, subsequent clinical responses in JAKi.R patients were associated with decreased inflammatory signaling accompanied by an increase in a “fate-flexible” CD8 T cell progenitor-like population. This fate-flexible population was linked to features of greater CD8 T cell plasticity. By contrast, NR patients had high baseline inflammation refractory to JAK inhibition. This persistent inflammatory and IFN-I signaling in NR patients was associated with CD8 T cell terminal differentiation and treatment failure. CONCLUSION As a therapeutic strategy to block the immunosuppressive effects of persistent IFN and/or chronic inflammation, JAK inhibition after initial anti–PD-1 is safe, feasible, and associated with durable and high response rates in NSCLC. JAK inhibition may be particularly beneficial in patients with elevated inflammation who have poor CD8 T cell responses to anti–PD-1 alone. In this study, JAK inhibition enhanced CD8 T cell plasticity by decreasing the inflammatory and IFN-I signals that drive terminal differentiation of CD8 T cells. However, some patients with the highest baseline levels of inflammation were largely unaffected by JAK1 inhibition and had progressive terminal CD8 T cell differentiation and disease progression. Our findings suggest that JAK inhibition can target chronic immunoregulatory functions of cytokine signaling that contribute to relapse during cancer immunotherapy and is a strategy warranting further preclinical and clinical investigation. JAK inhibitors to improve clinical and immune response to anti–PD-1 for lung cancer patients. In a clinical trial of patients with NSCLC treated with anti–PD-1, mitigating persistent IFN-I and inflammation with a JAK inhibitor decreased terminal differentiation of CD8 T cells and expanded fate-flexible CD8 T cell progenitors in responding patients. Patients with progressive disease had high baseline inflammation that minimally changed with JAK1 inhibition.
It is common practice for researchers to use antibodies to remove a specific cell type to infer its function. However, it is difficult to completely eliminate a cell type and there is often limited ...or no information as to how the cells which survive depletion are affected. This is particularly important for CD8+ T cells for two reasons. First, they are more resistant to mAb-mediated depletion than other lymphocytes. Second, targeting either the CD8α or CD8β chain could induce differential effects. We show here that two commonly used mAbs, against either the CD8α or CD8β subunit, can differentially affect cellular metabolism. Further, in vivo treatment leaves behind a population of CD8+ T cells with different phenotypic and functional attributes relative to each other or control CD8+ T cells. The impact of anti-CD8 antibodies on CD8+ T cell phenotype and function indicates the need to carefully consider the use of these, and possibly other "depleting" antibodies, as they could significantly complicate the interpretation of results or change the outcome of an experiment. These observations could impact how immunotherapy and modulation of CD8+ T cell activation is pursued.
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