P043 Small intestinal inflammation but not colitis drives pro-inflammatory nutritional antigen-specific T-cell response

Abstract Background Inflammatory bowel disease (IBD) represents a dysregulation of the mucosal immune system. The pathogenesis of Crohn’s disease (CD) and ulcerative colitis (UC) is linked to the loss of intestinal tolerance and barrier function. The healthy mucosal immune system has previously been shown to be inert against food antigens. Since the small intestine is the main contact surface for antigens and therefore the immunological response, the present study served to analyse food-antigen-specific T cells in the peripheral blood of IBD patients. Methods Peripheral blood mononuclear cells of CD, with an affected small intestine, and UC (colitis) patients, either active or in remission, were stimulated with the following food antigens: gluten, soybean, peanut and ovalbumin. Healthy controls and celiac disease patients were included as controls. Antigen-activated CD4+ T cells in the peripheral blood were analysed by a magnetic enrichment of CD154+ effector T cells and a cytometric antigen-reactive T-cell analysis (‘ARTE’ technology) followed by characterisation of the effector response. Results The effector T-cell response of antigen-specific T cells were compared between CD with small intestinal inflammation and UC where inflammation was restricted to the colon. Among all tested food antigens, the highest frequency of antigen-specific T cells (CD4+CD154+) was found for gluten. Celiac disease patients were included as control, since gluten has been identified as the disease-causing antigen. The highest frequency of gluten antigen-specific T cells was revealed in active CD when compared with UC, celiac disease on a gluten-free diet (GFD) and healthy controls. Ovalbumin-specific T cells were almost undetectable, whereas the reaction to soybean and peanut was slightly higher. But again, the strongest reaction was observed in CD with small intestinal involvement compared with UC. Remarkably, in celiac disease on a GFD only antigen-specific cells for gluten were detected. These gluten-specific T cells were characterised by up-regulation of the pro-inflammatory cytokines IFN-γ, IL-17A and TNF-α. IFN-g was exclusively elevated in CD patients with active disease. Gluten-specific T-cells expressing IL-17A were increased in all IBD patients. Furthermore, T cells of CD patients, independent of disease activity, revealed a high expression of the pro-inflammatory cytokine TNF-α. Conclusion The ‘ARTE’-technique allows to analyse and quantify food antigen specific T cells in the peripheral blood of IBD patients indicating a potential therapeutic insight. These data provide evidence that small intestinal inflammation in CD is key for the development of a systemic pro-inflammatory effector T-cell response driven by food antigens.

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T Cell Recognition of HCMV: Pan-Genome Analysis of Immunogenic Open-Reading Frames.

Blood ◽

10.1182/blood.v104.11.606.606 ◽

2004 ◽

Vol 104 (11) ◽

pp. 606-606 ◽

Cited By ~ 1

Author(s):

Louis J. Picker ◽

Andrew W. Sylwester ◽

Bridget L. Mitchell ◽

Cara Taormina ◽

Christian Pelte ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Peripheral Blood ◽

Cell Response ◽

Cd8 T Cell ◽

Cross Reactivity ◽

T Cell Response ◽

Cd4 T Cell ◽

Cell Responses

Abstract Human Cytomegalovirus (HCMV) is among the largest and most complex of known viruses with 150–200nm virions enclosing a double stranded 230kb DNA genome capable of coding for >200 proteins. HCMV infection is life-long, and for the vast majority of immune competent individuals clinically benign. Disease occurs almost exclusively in the setting of immune deficiency, suggesting that the stable host-parasite relationship that characterizes these infections is the result of an evolutionarily “negotiated” balance between viral mechanisms of pathogenesis and the host immune response. In keeping with, and perhaps because of this balance, the human CD4+ T cell response to whole HCMV viral lysates is enormous, with median peripheral blood frequencies of HCMV-specific cells ~5–10 fold higher than for analogous preparations of other common viruses. Although certain HCMV ORFs have been identified as targets of either the CD4+ or CD8+ T cell response, the specificities comprising the CD4+ T cell response, and both the total frequencies and component parts of the CD8+ T cell response are unknown. Here, we used cytokine flow cytometry and ~14,000 overlapping 15mer peptides comprising all 213 HCMV ORFs encoding proteins >100 amino acids in length to precisely define the total CD4+ and CD8+ HCMV-specific T cell responses and the HCMV ORFs responsible for these responses in 33 HCMV-seropositive, HLA-disparate donors. An additional 9 HCMV seronegative donors were similarly examined to define the extent to which non-HCMV responses cross-react with HCMV-encoded epitopes. We found that when totaled, the median frequencies of HCMV-specific CD4+ and CD8+ T cells in the peripheral blood of the seropositive subjects were 4.0% and 4.5% for the total CD4+ or CD8+ T cell populations, respectively (which corresponds to 9.1% and 10.5% of the memory populations, respectively). The HCMV-specific CD4+ and CD8+ T cell responses included a median 12 and 7 different ORFs, respectively, and all told, 73 HCMV ORFs were identified as targets for both CD4+ and CD8+ T cells, 26 ORFs as targets for CD8+ T cells alone, and 43 ORFS as targets for CD4+ T cells alone. UL55, UL83, UL86, UL99, and UL122 were the HCMV ORFs most commonly recognized by CD4+ T cells; UL123, UL83, UL48, UL122 and UL28 were the HCMV ORFs most commonly recognized by CD8+ T cells. The relationship between immunogenicity and 1) HLA haplotype and 2) ORF expression and function will be discussed. HCMV-seronegative individuals were non-reactive with the vast majority of HCMV peptides. Only 7 potentially cross-reactive responses were identified (all by CD8+ T cells) to 3 ORFs (US32, US29 and UL116) out of a total of almost 4,000 potential responses, suggesting fortuitous cross-reactivity with HCMV epitopes is uncommon. These data provide the first glimpse of the total human T cell response to a complex infectious agent, and will provide insight into the rules governing immunodominance and cross-reactivity in complex viral infections of humans.

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Assessment of T-cell immunity to SARS-CoV-2 in COVID-19 convalescents and vaccinated subjects, using TigraTest® SARS-CoV-2 ELISPOT kit

BIOpreparations Prevention Diagnosis Treatment ◽

10.30895/2221-996x-2021-21-3-178-192 ◽

2021 ◽

Vol 21 (3) ◽

pp. 178-192

Author(s):

D. A. Poteryaev ◽

S. G. Abbasova ◽

P. E. Ignatyeva ◽

O. M. Strizhakova ◽

S. V. Kolesnik ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Peripheral Blood ◽

Cell Response ◽

Human Peripheral Blood ◽

T Cell Response ◽

T Cell Immunity ◽

Cell Immunity

With the onset of the COVID-19 pandemic, a number of molecular-based tests have been developed to diagnose SARS-CoV-2 infection. However, numerous available serological tests lack sufficient sensitivity or specificity. They do not detect specific antibodies in a significant proportion of patients with PCR-confirmed COVID-19. There is evidence that some convalescents have a relatively short-lived humoral immunity. In contrast, a number of publications have shown that T-cell response to human coronaviruses, including SARS-CoV-1, MERS, and SARS-CoV-2, can be strong and long-term. Assessment of T-cell immunity to SARS-CoV-2 is important not only for stratification of risks and identification of potentially protected populations with immunity acquired as a result of previous infection, but also for determining immunogenicity and potential efficacy of vaccines under development. The existing methods of quantitative or semi-quantitative assessment of specific T-cell response are mainly used in scientific research and are not standardised. The aim of the study was to develop and verify experimentally a test kit to be used in a standardised procedure for in vitro determination of T-cells specific to SARS-CoV-2 antigens, in human peripheral blood. Materials and methods: the TigraTest® SARS-CoV-2 kit developed by GENERIUM, which determines the number of T-cells secreting interferon gamma in vitro, was tested in the study. Samples of venous blood of volunteers from three different groups were analysed in the study: presumably healthy volunteers; COVID-19 convalescents; individuals vaccinated against SARS-CoV-2. Results: the authors developed the TigraTest® SARS-CoV-2 kit for in vitro determination of T-cells specific to SARS-CoV-2 antigens in human peripheral blood, demonstrated its specificity and performed preliminary assessment of its sensitivity. The study analysed the range and magnitude of the T-cell response in convalescent and vaccinated individuals. A pronounced T-cell response was also shown in some individuals with no symptoms or with unconfirmed diagnosis. It was discovered that the mean T-cell response to peptides of the spike protein (S-protein) was higher in the vaccinated individuals than in the convalescent patients. A correlation was determined between the severity of the disease and the level of T-cell response. Specific contributions of various groups of antigens to the T-cell response after COVID-19 infection were also determined. Conclusions: the TigraTest® SARS-CoV-2 kit is a specific and sensitive tool for the assessment of T-cell immunity to the SARS-CoV-2 virus, which can also be used for vaccinated individuals. The kit may be used in clinical practice for comprehensive assessment of immunity to SARS-CoV-2.

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Mycobacterium bovis BCG Vaccination Induces Divergent Proinflammatory or Regulatory T Cell Responses in Adults

Clinical and Vaccine Immunology ◽

10.1128/cvi.00162-15 ◽

2015 ◽

Vol 22 (7) ◽

pp. 778-788 ◽

Cited By ~ 31

Author(s):

Mardi C. Boer ◽

Corine Prins ◽

Krista E. van Meijgaarden ◽

Jaap T. van Dissel ◽

Tom H. M. Ottenhoff ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Mycobacterium Bovis ◽

Regulatory T Cell ◽

Cell Response ◽

T Cell Response ◽

Bcg Vaccination ◽

Cell Responses ◽

Tnf Α ◽

Ifn Γ

ABSTRACTMycobacterium bovisbacillus Calmette-Guérin (BCG), the only currently available vaccine against tuberculosis, induces variable protection in adults. Immune correlates of protection are lacking, and analyses on cytokine-producing T cell subsets in protected versus unprotected cohorts have yielded inconsistent results. We studied the primary T cell response, both proinflammatory and regulatory T cell responses, induced by BCG vaccination in adults. Twelve healthy adult volunteers who were tuberculin skin test (TST) negative, QuantiFERON test (QFT) negative, and BCG naive were vaccinated with BCG and followed up prospectively. BCG vaccination induced an unexpectedly dichotomous immune response in this small, BCG-naive, young-adult cohort: BCG vaccination induced either gamma interferon-positive (IFN-γ+) interleukin 2-positive (IL-2+) tumor necrosis factor α-positive (TNF-α+) polyfunctional CD4+T cells concurrent with CD4+IL-17A+and CD8+IFN-γ+T cells or, in contrast, virtually absent cytokine responses with induction of CD8+regulatory T cells. Significant induction of polyfunctional CD4+IFN-γ+IL-2+TNF-α+T cells and IFN-γ production by peripheral blood mononuclear cells (PBMCs) was confined to individuals with strong immunization-induced local skin inflammation and increased serum C-reactive protein (CRP). Conversely, in individuals with mild inflammation, regulatory-like CD8+T cells were uniquely induced. Thus, BCG vaccination either induced a broad proinflammatory T cell response with local inflammatory reactogenicity or, in contrast, a predominant CD8+regulatory T cell response with mild local inflammation, poor cytokine induction, and absent polyfunctional CD4+T cells. Further detailed fine mapping of the heterogeneous host response to BCG vaccination using classical and nonclassical immune markers will enhance our understanding of the mechanisms and determinants that underlie the induction of apparently opposite immune responses and how these impact the ability of BCG to induce protective immunity to TB.

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Anaplasma marginale Infection with Persistent High-Load Bacteremia Induces a Dysfunctional Memory CD4+ T Lymphocyte Response but Sustained High IgG Titers

Clinical and Vaccine Immunology ◽

10.1128/cvi.00257-10 ◽

2010 ◽

Vol 17 (12) ◽

pp. 1881-1890 ◽

Cited By ~ 22

Author(s):

Sushan Han ◽

Junzo Norimine ◽

Kelly A. Brayton ◽

Guy H. Palmer ◽

Glen A. Scoles ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Persistent Infection ◽

Peripheral Blood ◽

Cell Response ◽

T Cell Responses ◽

Anaplasma Marginale ◽

High Load ◽

T Cell Response ◽

Cell Responses

ABSTRACT Control of blood-borne infections is dependent on antigen-specific effector and memory T cells and high-affinity IgG responses. In chronic infections characterized by a high antigen load, it has been shown that antigen-specific T and B cells are vulnerable to downregulation and apoptosis. Anaplasma marginale is a persistent infection of cattle characterized by acute and chronic high-load bacteremia. We previously showed that CD4+ T cells primed by immunization with an A. marginale outer membrane protein were rapidly deleted following infection. Furthermore, peripheral blood T cell responses to bacteria were not observed after acute infection was controlled, suggesting dysfunctional T cell priming to other A. marginale antigens. The current study more closely investigated the kinetics of A. marginale-specific CD4+ T cell responses primed during infection. Frequent sampling of peripheral blood and spleens revealed that antigen-specific CD4+ T cell responses were first detected at 5 to 7 weeks, but the responses were sporadic and transient thereafter. A similar pattern was observed in animals sampled weekly for nearly 1 year. Paradoxically, by 2 weeks of infection, cattle had developed high titers of A. marginale-specific IgG, which remained high throughout persistent infection. This dysfunctional CD4+ T cell response to infection is consistent with continual downregulation or deletion of newly primed effector T cells, similar to what was observed for immunization-induced T cells following A. marginale infection. The failure to establish a strong memory T cell response during A. marginale infection likely contributes to bacterial persistence.

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T cell phenotypes in COVID-19

Oxford Open Immunology ◽

10.1093/oxfimm/iqaa007 ◽

2020 ◽

Author(s):

Stephanie J Hanna ◽

Amy S Codd ◽

Ester Gea-Mallorqui ◽

D Oliver Scourfield ◽

Felix C Richter ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Peripheral Blood ◽

Cell Response ◽

T Cell Responses ◽

T Cell Response ◽

Immune Memory ◽

Cell Responses ◽

T Cell Phenotypes ◽

Cell Phenotypes

Abstract COVID-19 is characterised by profound lymphopenia in the peripheral blood, and the remaining T cells display altered phenotypes, characterised by a spectrum of activation and exhaustion. However, antigen-specific T cell responses are emerging as a crucial mechanism for both clearance of the virus and as the most likely route to long-lasting immune memory that would protect against re-infection. Therefore, T cell responses are also of considerable interest in vaccine development. Furthermore, persistent alterations in T cell subset composition and function post-infection have important implications for patients’ long-term immune function. In this review, we examine T cell phenotypes, including those of innate T cells, in both peripheral blood and lungs, and consider how key markers of activation and exhaustion correlate with, and may be able to predict, disease severity. We focus on SARS-CoV-2 specific T cells to elucidate markers which may indicate formation of antigen-specific T cell memory. We also examine peripheral T cell phenotypes in recovery and the likelihood of long-lasting immune disruption. Finally, we discuss T cell phenotypes in the lung as important drivers of both virus clearance and tissue damage. As our knowledge of the adaptive immune response to COVID-19 rapidly evolves, it has become clear that whilst some areas of the T cell response have been investigated in some detail, others, such as the T cell response in children remain largely unexplored. Therefore, this review will also highlight areas where T cell phenotypes require urgent characterisation.

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The Intestinal T Cell Response to α-Gliadin in Adult Celiac Disease Is Focused on a Single Deamidated Glutamine Targeted by Tissue Transglutaminase

Journal of Experimental Medicine ◽

10.1084/jem.191.4.603 ◽

2000 ◽

Vol 191 (4) ◽

pp. 603-612 ◽

Cited By ~ 418

Author(s):

Helene Arentz-Hansen ◽

Roman Körner ◽

Øyvind Molberg ◽

Hanne Quarsten ◽

Willemijn Vader ◽

...

Keyword(s):

T Cells ◽

Celiac Disease ◽

T Cell ◽

Cell Response ◽

Tissue Transglutaminase ◽

Critical Factor ◽

Great Majority ◽

T Cell Response ◽

Binding Studies ◽

Adult Celiac Disease

The great majority of patients that are intolerant of wheat gluten protein due to celiac disease (CD) are human histocompatibility leukocyte antigen (HLA)-DQ2+, and the remaining few normally express HLA-DQ8. These two class II molecules are chiefly responsible for the presentation of gluten peptides to the gluten-specific T cells that are found only in the gut of CD patients but not of controls. Interestingly, tissue transglutaminase (tTG)-mediated deamidation of gliadin plays an important role in recognition of this food antigen by intestinal T cells. Here we have used recombinant antigens to demonstrate that the intestinal T cell response to α-gliadin in adult CD is focused on two immunodominant, DQ2-restricted peptides that overlap by a seven-residue fragment of gliadin. We show that tTG converts a glutamine residue within this fragment into glutamic acid and that this process is critical for T cell recognition. Gluten-specific T cell lines from 16 different adult patients all responded to one or both of these deamidated peptides, indicating that these epitopes are highly relevant to disease pathology. Binding studies showed that the deamidated peptides displayed an increased affinity for DQ2, a molecule known to preferentially bind peptides containing negatively charged residues. Interestingly, the modified glutamine is accommodated in different pockets of DQ2 for the different epitopes. These results suggest modifications of anchor residues that lead to an improved affinity for major histocompatibility complex (MHC), and altered conformation of the peptide–MHC complex may be a critical factor leading to T cell responses to gliadin and the oral intolerance of gluten found in CD.

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T-Cell and B-Cell Responses After Vaccination against Influenza Virus and Pneumococcus in Chronic Phase CML Patients Treated with Tyrosine Kinase Inhibitors.

Blood ◽

10.1182/blood.v114.22.2214.2214 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2214-2214

Author(s):

Hugues de Lavallade ◽

Melanie Hart ◽

Ian H Gabriel ◽

Peter Kelleher ◽

Abdullah Alsuliman ◽

...

Keyword(s):

T Cells ◽

Influenza Virus ◽

T Cell ◽

B Cell ◽

Cell Response ◽

T Cell Responses ◽

T Cell Response ◽

Healthy Controls ◽

Cell Responses ◽

Tnf Α

Abstract Abstract 2214 Poster Board II-191 Imatinib (IM), nilotinib and dasatinib are remarkably effective as single-agent treatments for chronic myeloid leukemia (CML) in chronic phase (CP). However little is known on their potential impact on the immune system and to date no human in vivo data are available. Data from in vitro and animal studies on the effects of IM on the immune response have been contradictory ranging from impaired antigen-specific T-cell response to enhanced stimulation of tolerant T cells. In addition few data are available to assess potential immunomodulatory effects of the second-generation tyrosine kinase inhibitors (TKIs) nilotinib and dasatinib. Dasatinib has inhibitory activity against a broader range of protein kinases than imatinib including the Src family kinases Lck and Fyn, both of which are associated with T-cell receptor primary signal transduction pathways. Dasatinib may also inhibit B cell signaling through the Lyn pathway which may have potential implications for immunotherapeutic strategies. An understanding of the effects of different TKIs on the immune response will have implications for the development of immunotherapeutic strategies. The aim of this study was to prospectively analyze humoral and cellular immune responses to vaccination against influenza virus (Flu) and Pneumococcus in CP-CML patients treated with IM, dasatinib or nilotinib compared to healthy controls. Fifty CP-CML patients on standard dose TKIs (IM, n=22; dasatinib, n=15; nilotinib, n=13) and 15 healthy controls were vaccinated against Flu (Inflenza vaccine Ph. Eur. 2008/2009, CSL biotherapies) and pneumococcus (Pneumovax II, Sanofi Pasteur MSD). Samples were taken pre and at 1 and 3 months post-vaccination. Titers of IgM and IgG anti-pneumococcal were determined using ELISA technology. A positive response was defined as an IgM serum titer >100 U/ml at 1 month; IgG response was considered positive for IgG >200 U/ml at 1 or 3 months. To investigate possible correlation between B cell subsets and the pneumococcal humoral response we evaluated IgM memory B cells (CD19+ CD27+ IgMhigh IgDlow) and switched memory B cell (CD19+ CD27+ IgM- IgD-) subsets using flow cytometry. We analyzed the immunological T-cell response to influenza virus both quantitatively and qualitatively using flow cytometry for intracellular TNF-α, IFN-gamma and IL2 and the cytotoxicity marker CD107a. A response was considered positive if there was a minimum of 0.10% Flu-specific TNF-α producing T-cells and the percentage of antigen-specific TNF-α producing T-cells was 2-fold or higher compared to pre-vaccination level. Preliminary results on 28 patients and 11 healthy controls have been analyzed thus far. Significantly fewer patients on TKIs mounted an anti-pneumococcal IgM response (IgM serum titer > 100 U/ml) compared to healthy controls (9/28 versus 8/11, p=0.033). An anti-pneumococcal IgM response was detected in 20%, 37.5% and 40% of CML patients on dasatinib, nilotinib and IM respectively, and in 73% of the healthy controls. Moreover, patients on TKI had significantly lower levels of anti-pneumococcal IgM at 1 month compared to healthy controls (median, 84.5 U/ml, range 5 to 200 vs 200 U/ml, range 15 to 200, p=0.006). At 1 month the median levels of IgM in patients on dasatinib, nilotinib and IM were 55 U/ml (range, 12 to 172), 87 U/ml (range, 8-138) and 90 U/ml (range, 5 to 200) respectively. We have so far analyzed CD8 and CD4 T cell responses to Flu vaccination in 15 patients on TKI and 5 healthy controls. Prior to vaccination, T cell responses against Flu were detected in 4/15 patients on TKI and 1/5 healthy controls, indicating pre-existing memory T cell responses to Flu. In these subjects the T-cell response to Flu did not increase significantly after vaccination and as such the response was defined as negative. A significant T-cell response to Flu was seen in 7/15 patients on TKI (median 0.28% TNF-α+CD4+ T cells, range 0.10–2.25%) and in 3/5 healthy control (median 0.79% TNF-α+CD4+T cells, range 0.12–1.34%). These preliminary results suggest that in patients with CML on TKIs the IgM B cell response to vaccination with Pneumovax is significantly impaired compared to healthy controls. We have as yet not detected a significant difference in T-cell response following vaccination with Flu in CML patients on TKIs compared to healthy controls. We are in the process of analyzing the remaining samples. Disclosures: Marin: Novartis: Consultancy, Research Funding.

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Ibrutinib Can Modulate the T Cell Response in Chronic Lymphocytic Leukemia By Reducing PD1/PDL1 Interactions

Blood ◽

10.1182/blood.v126.23.1737.1737 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1737-1737 ◽

Cited By ~ 6

Author(s):

Kayo Kondo ◽

Jan A. Burger ◽

Keating Micheal ◽

Jamie Tran ◽

Muharrem Muftuoglu ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cell Response ◽

Research Funding ◽

Cell Receptor ◽

T Cell Response ◽

T Cell Subsets ◽

Cell Recovery ◽

Tnf Α ◽

Pre Treatment

Abstract INTRODUCTION: The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib is a covalent inhibitor of BTK, a member of the B-cell receptor (BCR) signaling pathway and induces objective clinical responses in the majority of CLL patients (Byrd et al., NEJM 2013). Interestingly this drug also inhibits L2-inducible T cell kinase (ITK), an essential enzyme for the development and effector function of Th2 and Th17 cells, and has been shown to shift the balance towards a Th1 response. The purpose of the study was to determine how ibrutinib influences the Th1/Th17/T regulatory cell response, expression of immune checkpoint blockade molecules on T cells and the functional pathogen-specific T cell recovery. METHODS: Here we present data from a clinical trial of ibrutinib versus ibrutinib + rituximab in previously treated patients (NCT02007044). Peripheral blood and serum were collected at baseline, 3 months and 6 months during therapy. Multicolor flow cytometry was used to characterize B cell subsets, T-cell subsets, expression of PD-1, PD-L1 and CTLA-4 and T-cell effector function. For statistical analysis of pre-treatment to on-treatment measurements the paired Student t-test was used. RESULTS: Here we report on the phenotypic and functional recovery of immune subsets in 41 CLL patients treated with ibrutinib (n=17) or ibrutinib + rituximab (n=25). Both PD-1 and PD-L1 were expressed at high levels on CLL cells. Interestingly, by 3 and 6 months, there was a significant decrease in PD-1 expression from a pre-treatment median of 15% to 4% (at 3 months) and 3% (at 6 months; P<0.0001). Similarly, PD-L1 levels decreased from 5% to 3% and 2% respectively (P=0.004) (Fig. 1). We next sought to determine the functional impact of ibrutinib therapy on T cell subsets and function. After an initial reduction from a pretreatment level of4800/µL to 3000/µL at 3 months (P=0.003), CD3+ T cells increased to 4000 (µL) by 6 months; P=0.03. This was associated with a significant down-regulation of PD-1 expression on T cells from 28% pre-treatment to 24% and 21% at 3 and 6 months respectively (Fig.2 ) (P<0.0001). A significant reduction in the frequencies of regulatory T cells (Teg) (8% vs. 7% vs 6% respectively; P=0.004) was also documented. Ibrutinib has been reported to skew the T cell response toward a Th1 profile. We stimulated PBMC with PMA/Inomycin and performed intracellular staining for IFN-γ, IL-2, TNF-α and IL-17. Following ibrutinib therapy, there was a significant improvement in the CD8+ IFN-γ (P=0.04) and TNF-α response (P=0.01), and a reduction in the CD4+IL-17 response. To understand the functional relevance of these results, we are currently analyzing the CD8+ T cell response to stimulation with CEF (epitopes derived from CMV, EBV and Influenza) as a surrogate for pathogen-specific T cell recovery. CONCLUSION: Based on these data we propose that ibrutinib therapy can modulate the T cell response through multiple mechanisms which include (i) direct inhibition of ITK and skewing of the T cell response toward a Th1 profile; (ii) reduction in PD1/PDL1 expression on B and T cells and (iii). suppression of Tregs. It is unclear how ibrutinib influences the PD1/PDL1 interaction and whether this is a direct effect of the drug on essential components of B and T cell-receptor signaling or whether it is an indirect effect related to a reduction in the leukemia burden. Mechanistic studies to understand how ibrutinib modulates the PD1/PL1 axis are currently underway. Figure 1. Ibrutinib therapy is associated with a reduction in PDL1 expression on the surface of CD19+ B cells. Figure 1. Ibrutinib therapy is associated with a reduction in PDL1 expression on the surface of CD19+ B cells. Figure 2. Ibrutinib therapy is associated with a reduction in PD1 expression on the surface of CD3+ T cells. Figure 2. Ibrutinib therapy is associated with a reduction in PD1 expression on the surface of CD3+ T cells. Disclosures Burger: Pharmacyclics LLC, an AbbVie Company: Research Funding. Wierda:Glaxo-Smith-Kline Inc.: Research Funding; Celgene Corp.: Consultancy. Rezvani:Pharmacyclics: Research Funding.

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Interferon-α, but not the ABL-kinase inhibitor imatinib (STI571), induces expression of myeloblastin and a specific T-cell response in chronic myeloid leukemia

Blood ◽

10.1182/blood-2002-02-0659 ◽

2003 ◽

Vol 101 (1) ◽

pp. 259-264 ◽

Cited By ~ 102

Author(s):

Andreas Burchert ◽

Stefan Wölfl ◽

Manuel Schmidt ◽

Cornelia Brendel ◽

Barbara Denecke ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Chronic Myeloid Leukemia ◽

Peripheral Blood ◽

Cell Response ◽

Myeloid Leukemia ◽

Cytotoxic T Cells ◽

T Cell Response ◽

Interferon Α ◽

Hematopoietic Stem

Abstract Chronic myeloid leukemia (CML) is a clonal disease of hematopoietic stem cells caused by a reciprocal translocation of the long arms of chromosomes 9 and 22. In human leukocyte antigen A*0201+ (HLA-A*0201+) individuals, response after interferon-α (IFN-α) was shown to be associated with the emergence of CML-specific cytotoxic T cells that recognize PR-1, a myeloblastin (MBN)–derived nonapeptide. In contrast, imatinib potently induces remissions from CML by specific inhibition of the ABL tyrosine kinase. Here, we explored molecular regulations associated with CML responses under different treatment forms using cDNA-array. Expression of MBN was found to be down-regulated in remission under imatinib therapy (0 of 7MBN+ patients). In contrast, MBNtranscription was readily detectable in the peripheral blood in 8 of 8 tested IFN-α patients in complete remission (P = .0002). IFN-α–dependent MBNtranscription was confirmed in vitro by stimulation of peripheral blood mononuclear cells (PBMCs) with IFN-α and by IFN-α–mediated activation of the MBN promoter in reporter gene assays. Finally, with the use of HLA-A*0201–restricted,MBN-specific tetrameric complexes, it was demonstrated that all of 4 IFN-α–treated patients (100%), but only 2 of 11 imatinib patients (19%), in complete hematological or cytogenetic remission developed MBN-specific cytotoxic T cells (P = .011). Together, the induction of MBNexpression by IFN-α, but not imatinib, may contribute to the specific ability of IFN-α to induce an MBN-specific T-cell response in CML patients. This also implies that the character of remissions achieved with either drug may not be equivalent and therefore a therapy modality combining IFN-α and imatinib may be most effective.

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Mechanisms that allow vaccination against an oncolytic vesicular stomatitis virus-encoded transgene to enhance safety without abrogating oncolysis

Scientific Reports ◽

10.1038/s41598-021-94483-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Amanda W. K. AuYeung ◽

Robert C. Mould ◽

Ashley A. Stegelmeier ◽

Jacob P. van Vloten ◽

Khalil Karimi ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Vesicular Stomatitis Virus ◽

Cell Response ◽

Viral Infections ◽

T Cell Response ◽

Oncolytic Viruses ◽

Oncolytic Virotherapy ◽

Cell Immunity ◽

Vesicular Stomatitis

AbstractVaccination can prevent viral infections via virus-specific T cells, among other mechanisms. A goal of oncolytic virotherapy is replication of oncolytic viruses (OVs) in tumors, so pre-existing T cell immunity against an OV-encoded transgene would seem counterproductive. We developed a treatment for melanomas by pre-vaccinating against an oncolytic vesicular stomatitis virus (VSV)-encoded tumor antigen. Surprisingly, when the VSV-vectored booster vaccine was administered at the peak of the primary effector T cell response, oncolysis was not abrogated. We sought to determine how oncolysis was retained during a robust T cell response against the VSV-encoded transgene product. A murine melanoma model was used to identify two mechanisms that enable this phenomenon. First, tumor-infiltrating T cells had reduced cytopathic potential due to immunosuppression. Second, virus-induced lymphopenia acutely removed virus-specific T cells from tumors. These mechanisms provide a window of opportunity for replication of oncolytic VSV and rationale for a paradigm change in oncolytic virotherapy, whereby immune responses could be intentionally induced against a VSV-encoded melanoma-associated antigen to improve safety without abrogating oncolysis.

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