Hanspeter Pircher

Max Planck Institute of Immunobiology and Epigenetics | IE

SYNTAXIN-11 (STX11) is a SNARE protein that mediates the fusion of cytotoxic granules with the plasma membrane at the immunological synapses of CD8 T or NK cells. Autosomal recessive inheritance of deleterious STX11 variants impairs cytotoxic granule exocytosis, causing familial hemophagocytic lymphohistiocytosis type 4 (FHL-4). In several FHL-4 pa...

Across the animal kingdom, multivalency discriminates antibodies from all other immunoglobulin superfamily members. The evolutionary forces conserving multivalency above other structural hallmarks of antibodies remain, however, incompletely defined. Here, we engineer monovalent either Fc-competent or -deficient antibody formats to investigate mecha...

NK1.1⁺ cells found in salivary glands (SG) represent a unique cell population of innate lymphoid cells (ILC) with characteristics of both conventional NK cells and ILC1. Here, we demonstrate that these NK1.1⁺ cells limit the accumulation and differentiation of virus‐specific tissue‐resident memory CD8⁺ T cells (TRM cells) in SG of mice infected wit...

Familial hemophagocytic lymphohistiocytosis (FHL) is a hyperinflammatory syndrome affecting patients with genetic cytotoxicity defects. Perforin‐deficient (PKO) mice recapitulate the full clinical picture of FHL after infection with lymphocytic choriomeningitis virus (LCMV). Hyperactivated CD8⁺ T cells and IFNγ have been identified as the key drive...

During acute viral infections in mice, IL‐7Rα and KLRG1 together are used to distinguish the short‐lived effector cells (SLEC; IL‐7RαloKLRGhi) from the precursors of persisting memory cells (MPEC; IL‐7RαhiKLRG1lo). We here show that these markers can be used to define distinct subsets in the circulation and lymph nodes during the acute phase and in...

Hyper‐activated or deviated immune responses can result in immunopathological diseases. Paradoxically, immunodeficiency represents a frequent cause of such immune‐mediated pathologies. Immunopathological manifestations are commonly treated by immunosuppression, but in situations in which immunodeficiency is the basis of disease development, enhanci...

Infection of C57BL/6 mice with lymphocytic choriomeningitis virus (LCMV) strain Armstrong (Arm) induces an acute infection with rapid virus clearance by CD8⁺ T cells independently of CD4⁺ T cell help. Residual viral antigen may, however, persist for a prolonged time. Here, we demonstrate that mice that had been transiently depleted of CD4⁺ T cells...

Infection of specific pathogen-free mice with lymphocytic choriomeningitis virus (LCMV) is a widely used model to study antiviral T-cell immunity. Infections in the real world, however, are often accompanied by coinfections with unrelated pathogens. Here we show that in mice, systemic coinfection with E. coli suppresses the LCMV-specific cytotoxic...

Background & Aims Phenotypic and functional natural killer (NK)-cell alterations are well described in chronic hepatitis B virus (cHBV) infection. However, it is largely unknown whether these alterations result from general effects on the overall NK-cell population or the emergence of distinct NK-cell subsets. Human cytomegalovirus (HCMV) is common...

Memory CD8+ T cells are essential in orchestrating protection from re‐infection. Hallmarks of virus‐specific memory CD8+ T cells are the capacity to mount recall responses with rapid induction of effector cell function and antigen‐independent survival. Growing evidence reveals that even chronic infection does not preclude virus‐specific CD8+ T‐cell...

Cytotoxic T lymphocytes (CTLs) play a key role in the control of lymphocytic choriomeningitis virus (LCMV) infection. In C57BL/6 mice (H-2b), the CTL response is mainly directed against epitopes from the LCMV glycoprotein (GP) and the nucleoprotein (NP) which represent the two major viral proteins. The role of GP- versus NP-derived epitopes for vir...

Cytomegalovirus (CMV) is a common opportunistic infection encountered in renal transplant recipients (RTRs) and may be reactivated without symptoms at any time post-transplant. We describe how active and latent CMV affect T-cell subsets in RTRs who are stable on maintenance therapy. T-cell responses to CMV were assessed in RTRs (n = 54) >2 years po...

Immune homeostasis requires the tight, tissue-specific control of the different CD4(+) Foxp3(+) regulatory T cells (Treg) populations. The cadherin-binding inhibitory receptor KLRG1 is expressed by a subpopulation of Treg with GATA3(+) effector phenotype. Although such Treg are important for the immune balance, especially in the gut, the role of KL...

The salivary glands (SGs) of virus-immune mice contain substantial numbers of tissue-resident memory CD8+ T cells (TRM cells) that can provide immunity to local infections. Integrins regulate entry of activated T cells into non-lymphoid tissues but the molecules that mediate migration of virus-specific CD8+ T cells to the SGs have not yet been defi...

Inadequate antibody responses and perturbed B cell compartments represent hallmarks of persistent microbial infections, but the mechanisms whereby persisting pathogens suppress humoral immunity remain poorly defined. Using adoptive transfer experiments in the context of a chronic lymphocytic choriomeningitis virus infection of mice, we have documen...

CD8(+) T cells and NK cells protect from viral infections by killing virally infected cells and secreting interferon-γ. Several inhibitory receptors limit the magnitude and duration of these anti-viral responses. NKG2A, which is encoded by Klrc1, is a lectin-like inhibitory receptor that is expressed as a heterodimer with CD94 on NK cells and activ...

Sustained Ag persistence in chronic infection results in a deregulated CD8(+) T cell response that is characterized by T cell exhaustion and cell death of Ag-specific CD8(+) T cells. Yet, the underlying transcriptional mechanisms regulating CD8(+) T cell exhaustion and cell death are poorly defined. Using the experimental mouse model of lymphocytic...

The inhibitory receptor KLRG1 and the integrin αE (CD103) are expressed by CD8(+) T cells and both are specific for E-cadherin. However, KLRG1 ligation by E-cadherin inhibits effector T-cell function, whereas binding of CD103 to E-cadherin enhances cell-cell interaction and promotes target cell lysis. Here, we demonstrate that KLRG1 and CD103 expre...

Unlabelled: After the resolution of the acute phase of infection, otherwise quiescent antigen-experienced CD8(+) T cells confer rapid protection upon reinfection with viral pathogens or, in the case of persistent viruses, help to maintain control of the infection. Depending on the type of virus, antigen-specific CD8(+) T cells have distinct traits...

Defining the minimal thresholds for effective antiviral T cell immunity is important for clinical decisions in immunodeficient patients. TCR signaling is critical for T cell development, activation, and effector functions. In this article, we analyzed which of these TCR-mediated processes is limiting for antiviral immunity in a mouse strain with re...

Unlabelled: Human cytomegalovirus (hCMV) infection is characterized by a vast expansion of resting effector-type virus-specific T cells in the circulation. In mice, interleukin-7 receptor α (IL-7Rα)-expressing cells contain the precursors for long-lived antigen-experienced CD8(+) T cells, but it is unclear if similar mechanisms operate to maintain...

Rationale: There is mounting evidence of a higher incidence of coronary heart disease in cytomegalovirus-seropositive individuals. Objective: The aim of this study was to investigate whether acute myocardial infarction triggers an inflammatory T-cell response that might lead to accelerated immunosenescence in cytomegalovirus-seropositive patient...

Background T-cell exhaustion seems to play a critical role in CD8+ T-cell dysfunction during chronic viral infections. However, up to now little is known about the mechanisms underlying CD4+ T-cell dysfunction during chronic hepatitis B virus (CHB) infection and the role of inhibitory molecules such as programmed death 1 (PD-1) for CD4+ T-cell fail...

Dendritic cells (DC) presenting tumor antigens are crucial to induce potent T cell-mediated anti-tumor immune responses. Therefore DC-based cancer vaccines have been established for therapy, however clinical outcomes are often poor and need improvement. Using a mouse model of B16 melanoma, we found that the route of preventive DC vaccination critic...

Cell-based immunotherapy strategies target tumors directly (via cytolytic effector cells) or aim at mobilizing endogenous anti-tumor immunity. The latter approach includes dendritic cells (DC) most frequently in the form of in vitro cultured peripheral blood monocytes-derived DC. Human blood γδT cells are selective for a single class of non-peptide...

Key Points Lack of KLRG1 and T-bet expression is a unique feature of DNT and subsets of single positive T cells in ALPS patients. Genetic, phenotypic, and transcriptional evidence indicates that DNT in ALPS patients derive from both CD4+ and CD8+ T cells.

The killer cell lectin-like receptor G1 (KLRG1) is a cadherin-binding inhibitory receptor expressed by NK cells and differentiated T cells. Here we surprisingly found that a fraction of KLRG1 molecules expressed in the murine A5 T-cell line and in IL-2-activated NK cells form disulfide-linked heteromers with the transferrin receptor (TfR). Fluoresc...

Under conditions of chronic antigen stimulation, such as persistent viral infection and cancer, CD8 T cells may diminish effector function, which has been termed “exhaustion.” Expression of inhibitory Receptors (iRs) is often regarded as a hallmark of “exhaustion.” Here we studied the expression of eight different iRs by CD8 T cells of healthy huma...

Redirecting Ag specificity by transfer of TCR genes into PBLs is an attractive method to generate large numbers of cytotoxic T cells for immunotherapy of cancer and viral diseases. However, transferred TCR chains can pair with endogenous TCR chains, resulting in the formation of mispaired TCR dimers and decreased or unspecific reactivity. TCR gene...

Cytotoxic T cells (CTL) play a critical role in the clearance of respiratory viral infections, but also contribute to disease manifestations. Here, we infected mice with a genetically modified pneumonia virus of mice (PVM) that allowed visualization of virus-specific CTL and infected cells in situ. The first virus-specific T cells entered the lung...

Altered numbers and functions of T cells have previously been demonstrated in chronic lymphocytic leukemia (CLL) patients. However, dynamics and specific T-cell subset alterations have not been studied in great detail. Therefore, we studied CLL blood lymphocyte subsets of individual patients in a longitudinal manner. Dynamic expansions of blood CD4...

The thymus is a primary lymphoid organ responsible for production and selection of T cells. Nonetheless, mature T cells and in particular activated T cells can re-enter the thymus. Here, we identified memory CD8(+) T cells specific for lymphocytic choriomeningitis virus (LCMV) or vaccinia virus (VV) in the thymus of mice long-time after the infecti...

CD8(+) T cells have an essential role in controlling LCMV infection in mice. Here, we examined the contribution of humoral immunity, including non-neutralizing antibodies (Abs), in this infection induced by low virus inoculation doses. Mice with impaired humoral immunity readily terminated infection with the slowly replicating LCMV strain Armstrong...

The human polyomavirus BK (BKV) establishes a latent and asymptomatic infection in the majority of the population. In immunocompromised individuals the virus frequently (re)activates and may cause severe disease such as interstitial nephritis and hemorrhagic cystitis. Currently, the therapeutic options are limited to reconstitution of the antiviral...

Objectives: Killer cell lectin-like receptor G1 (KLRG1) is an NK cell marker also expressed on T cells showing an immunosenescent phenotype. KLRG1 binding to its ligand E-cadherin inhibits functional responses. It was recently shown that soluble E-cadherin (sE-cadherin) also influences KLRG1 signalling, although its involvement in arthritis is unk...

Dynamic exercise evokes a rapid redeployment of cytotoxic T cell subsets with high surface expression of β2 adrenergic receptors, presumably to enhance immunosurveillance during acute stress. As this response is affected by age and infection history, this study examined latent CMV infection as a potential confounder to age-related differences in bl...

The expression of T cell differentiation markers is known to increase during Mycobacterium tuberculosis infection, and yet the biological role of such markers remains unclear. We examined the requirement of the T cell differentiation marker killer cell lectin-like receptor G1 (KLRG1) during M. tuberculosis infection using mice deficient in KLRG1. K...

Increased T-bet levels and senescence in CD8 T cells from aged individuals as possible mechanisms for decreased influenza-specific functionality. Aged individuals have increased morbidity and mortality following influenza and other viral infections, despite previous exposure or vaccination. Mouse and human studies suggest increased senescence and/o...

With the advent of primary PCI (PPCI), reperfusion is achieved in almost all patients presenting with acute myocardial infarction. However, despite multiple trials, reperfusion injury has not been successfully dealt with so far. In mouse models, CD4(+) T lymphocytes (T cells) have been shown to be crucial instigators of reperfusion injury. Our goal...

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The transfer of T cell receptor (TCR) genes by viral vectors represents a promising technique to generate antigen-specific T cells for adoptive immunotherapy. TCR-transduced T cells specific for infectious pathogens have been described, but their protective function in vivo has not yet been examined. Here, we demonstrate that CD8 T cells transduced...

The killer cell lectin-like receptor G1 (KLRG1) is a cadherin-binding inhibitory receptor expressed by NK and T cells in humans and mice. Although structural and ligand-binding properties of human (h) and mouse (m) KLRG1 are very similar, KLRG1-mediated inhibition under physiological conditions is only observed with human lymphocytes. Using a well-...

Previous mouse and human studies have demonstrated that direct IFN-α/β signaling on naive CD8 T cells is critical to support their expansion and acquisition of effector functions. In this study, we show that human naive CD8 T cells primed in the presence of IFN-α possess a heightened ability to respond to homeostatic cytokines and to secondary Ag s...

Background. Despite advances in immunosuppressive regimens, acute graft-versus-host disease remains a frequent complication of allogeneic hematopoietic cell transplantation. Pathogenic donor T cells are dependent on correct attachment of small GTPases to the cell membrane, mediated by farnesyl- or geranylgeranyl residues, which therefore constitute...

Inhibitory receptors mediate CD8 T-cell hyporesponsiveness against cancer and infectious diseases. PD-1 and CTLA-4 have been extensively studied, and blocking antibodies have already shown clinical benefit for cancer patients. Only little is known on extended co-expression of inhibitory receptors and their ligands. Here we analyzed the expression o...

Expression of inhibitory receptors on self/tumor-specific CD8 T-cells. PBMC from four patients were enriched for CD8 T-cells using magnetic beads. Melan-A-, NY-ESO-1- and MAGE-A10-specific CD8 T-cells were identified by staining with CD8-specific antibody and tetramers as described in the Materials and Methods section. Positivity for the inhibitory...

Inhibitory receptors and identified ligands. For each of the eight inhibitory receptors investigated the known ligands are listed. (PDF)

Influence of priming on expression of inhibitory receptors. Samples from healthy donors (HD) or patients before vaccination (before vacc.) or after peptide+IFA vaccination, either with or without CpG-ODN, were enriched for CD8 using magnetic beads. Melan-A-specific T-cells were identified using CD8-specific antibody and tetramer as described in the...

Influence of the microenvironment on expression of inhibitory receptors. Samples from patients vaccinated either with (red) or without (black) CpG-ODN were enriched for CD8 using magnetic beads. Melan-A-specific T-cells were identified using CD8-specific antibody and tetramer as described in the Materials and Methods section. Positivity for the inh...

Gating strategy, and inhibitory receptor expression in total CD8 T-cells. (A) Gating strategy. Expression of inhibitory receptors was analyzed on total CD8+ T-cells, on naive, central memory, effector memory and effector memory RA+ cells (based on CCR7 and CD45RA expression) and on tetramer positive cells. Staining 1 and staining 2 each contained f...

Expression of inhibitory receptors on tumor- and virus-specific CD8 T-cells. Samples from blood from patients were enriched for CD8 T-cells using magnetic beads. Melan-A-, CMV- and EBV-specific CD8 T-cells were identified by staining with CD8-specific antibody and tetramers as described in the Materials and Methods section. Positivity for the inhib...

Tumor-specific T cells are frequently induced naturally in melanoma patients and infiltrate tumors. It is enigmatic why these patients fail to experience tumor regression. Given that CD8(+) T cells mediate antigen-specific killing of tumor cells, the focus of this study was to identify alterations in the differentiation of CD8(+) residing at the tu...

Background: Primary PCI (PPCI) has substantially improved clinical outcomes of patients with acute ST elevation myocardial infarction (STEMI). However, myocardial ischemia-reperfusion (I/R) injury still remains an important clinical problem. CD4+ T-lymphocytes have been shown to promote I/R injury in a mouse model. It is unknown though, whether T-c...

The salivary glands are important effector sites for IgA-mediated humoral immunity to protect oral surfaces. Within murine submandibular glands (SMG), we identified a memory CD8 T-cell population that exhibited a unique cell-surface phenotype distinct from memory CD8 T cells in spleen but similar to memory T cells resident in the intraepithelial ly...

NK-cells and γδ T-cells are cytotoxic effectors of the immune system that are preferentially mobilized into the blood compartment in response to acute stress and exercise. While infection history is known to alter the phenotype and exercise-responsiveness of CD8+ T-cells, the influence of latent cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in...

PD-1 expression is elevated in both influenza-specific and total CD8 T cells from older individuals. PD-1 levels were measured by flow cytometry direct ex vivo in conjunction with tetramer staining for HLA–A2 positive young and older donors. Left: Median fluorescence intensity (MFI) of PD-1 in influenza M1-specific CD8 T cells. Right: Representativ...

T cells specific for persistent pathogens accumulate with age and express markers of immune senescence. In contrast, much less is known about the state of T cell memory for acutely infecting pathogens. Here we examined T cell responses to influenza in human peripheral blood mononuclear cells from older (>64) and younger (<40) donors using whole vir...

Common variable immunodeficiency (CVID) is a heterogeneous antibody deficiency syndrome with alterations in T cell regulation and function in a subgroup of patients. We assessed phenotype and function of bulk and virus-specific CD8+ T cells of a cohort of 34 HLA-A2+ CVID patients by pentamer technology and flow cytometry in relationship to their im...

Senescent T-cells accumulate with age, lowering the naïve T-cell repertoire and increasing host infection risk. As this response is likely to be influenced by certain lifestyle factors, we examined the association between aerobic fitness (VO(2max)) and the age-related accumulation of senescent T-cells. Blood lymphocytes from 102 healthy males (18-6...

Lymphocytes mediate cytotoxicity by polarized release of the contents of cytotoxic granules toward their target cells. Here, we have studied the role of the calcium release-activated calcium channel ORAI1 in human lymphocyte cytotoxicity. Natural killer (NK) cells obtained from an ORAI1-deficient patient displayed defective store-operated Ca(2+) en...

913 Altered numbers and functions of T-cells have previously been demonstrated in chronic lymphocytic leukemia (CLL) patients. However, dynamics and specific T-cell subset alterations have not been studied in great detail. Therefore, we determined numbers of blood lymphocyte subsets of CLL patients in a longitudinal manner. We found that dynamic ex...

Natural killer (NK) cells are innate immune lymphocytes that express a heterogeneous repertoire of germline-encoded receptors and undergo a distinct pattern of maturation. CD57 is a marker of terminal differentiation on human CD8(+) T cells. Very few newborn or fetal NK cells express CD57; however, the frequency of CD57-bearing NK cells increases w...

CD8(+) T cells at the earliest stage of effector generation have not been identified at tumor site of melanoma patients. Such early effectors, if present, should be characterized by a specific phenotype, distinct from that expressed at later stages of the antigen-induced differentiation program, by short-lived effector cells, memory precursors, and...

Multi-inhibitory receptor analysis of HCV-specific CD8+ T cells. The co-expression of PD-1, 2B4, CD160 and KLRG1 on CD8+tetramer+ T cells was determined as follows: A) The tetramer+ HCV-specific CD8+ T cell population was gated on CD8+ T cells in the lymphocyte gate. Gates for CD127 and inhibitory receptor expression were determined on the total CD...

Analysis of Bcl-2 expression. In a total of 8 patients, Bcl-2 expression on HCV-specific CD8+ T cells was analyzedAnalysis of Bcl-2 expression. In a total of 8 patients, Bcl-2 expression on HCV-specific CD8+ T cells was analyzed after cell permeabiliztion. Original data plots from patient 4 are shown and the MFI of tetramer-positive cells is displa...

Gating strategy for the assessment of CD127 frequencies. Virus-specific CD8+ T cells were determined by tetramer staining and thresholds for CD127 positivity defined by FMO controls. Representative pseudocolor plots are shown for (A) CD127hi HCV-specific CD8+ T cells (pt. 4-NS3-1406) and (B) CD127lo HCV-specific CD8+ T cells (pt. 4-NS5-2594). (0.43...

Exhausted CD8+ T cell responses during chronic viral infections are defined by a complex expression pattern of inhibitory receptors. However, very little information is currently available about the coexpression patterns of these receptors on human virus-specific CD8+ T cells and their correlation with antiviral functions, T cell differentiation an...

The killer cell lectin-like receptor G1 (KLRG1) is expressed by NK and T-cell subsets and recognizes members of the classical cadherin family. KLRG1 is widely used as a lymphocyte differentiation marker in both humans and mice but the physiological role of KLRG1 in vivo is still unclear. Here, we generated KLRG1-deficient mice by homologous recombi...

Acute bouts of aerobic exercise are known to mobilize antigen-experienced CD8+ T-cells expressing the cell surface marker of senescence, KLRG1, into the blood. It is not known; however if this is due to a selective mobilization of terminally differentiated T-cells (i.e., KLRG1 +/CD28-/CD57+) or a population of effector memory T-cells (i.e., KLRG1+/...

Renal cell carcinoma is frequently infiltrated by cells of the immune system. This makes it important to understand interactions between cancer cells and immune cells so they can be manipulated to bring clinical benefit. Here, we analyze subsets and functions of T lymphocytes infiltrating renal cell tumors directly ex vivo following mechanical disa...

Antigen-specific immunotherapy is an attractive strategy for cancer control. In the context of antiviral vaccines, adenoviral vectors have emerged as a favorable means for immunization. Therefore, we chose a strategy combining use of these vectors with another successful approach, namely linkage of the vaccine antigen to invariant chain (Ii). To ev...

Alternatively activated macrophages (AAMs), triggered by interleukin-4 (IL-4) and IL-13, play a modulating role during Th2 cytokine-driven pathologies, but their molecular armament remains poorly characterized. Here, we established E-cadherin (Cdh1) as a selective marker for IL-4/IL-13-exposed mouse and human macrophages, which is STAT6-dependently...

The cytolytic activity of natural killer (NK) cells is regulated by inhibitory receptors that detect the absence of self molecules on target cells. Structural studies of missing self recognition have focused on NK receptors that bind MHC. However, NK cells also possess inhibitory receptors specific for non-MHC ligands, notably cadherins, which are...

The killer cell lectin-like receptor G1 (KLRG1) is an inhibitory receptor expressed by memory T cells and NK cells in man and mice. It is frequently used as a cell differentiation marker and members of the cadherin family are ligands for KLRG1. The present study provides new insights into the interaction of mouse KLRG1 with E-cadherin. Firstly, we...

We determined the efficacy of in vitro expanded P14 TCR transgenic CD8 T cells to mediate tumor cell elimination and to protect against viral infection in mice. Contrary to previous studies, an adoptive transfer model without lymphodepletion, vaccination or cytokine treatment was used. Antigen-activated P14 T cells cultured in IL-2-containing mediu...

Senescent T-lymphocytes are antigen-experienced cells that express the killer-cell lectin-like receptor G1 (KLRG1) and/or CD57; fail to clonally expand following further antigenic stimulation and prevail in the resting blood of older adults compared to the young. Physical exercise mobilises T-lymphocytes into the bloodstream and is therefore a mode...