scholarly journals A systems approach to the characterization and classification of T-cell responses

2017 ◽  
Author(s):  
Shinobu Yamamoto ◽  
Elizabeth Whalen ◽  
Daisuke Chujo ◽  
Durgha Nattamai ◽  
Nicole Baldwin ◽  
...  
Keyword(s):  
T Cell ◽  
Systems Approach ◽  
Meta Analysis ◽  
A Priori ◽  
T Cell Responses ◽  
Cell Responses ◽  
Wide Range

AbstractTypes of T-cell responses are categorized on the basis of a limited number of molecular markers selected usinga prioriknowledge about T-cell immunobiology. We sought to develop a novel systems-based approach for the creation of an unbiased framework enabling assessment of antigenic-peptide specific T-cell responsesin vitro. A meta-analysis of transcriptome data from PBMCs stimulated with a wide range of peptides identified patterns of gene regulation that provided an unbiased classification of types of antigen-specific responses. Further analysis yielded new insight about the molecular processes engaged following antigenic stimulation. This led for instance to the identification of transcription factors not previously studied in the context of T-cell differentiation. Taken together this profiling approach can serve as a basis for the unbiased characterization of antigen-specific responses and as a foundation for the development of novel systems-based immune profiling assays.

scholarly journals Regulated Antigen Expression in Live RecombinantSalmonella enterica Serovar Typhimurium Strongly Affects Colonization Capabilities and Specific CD4+-T-Cell Responses

2001 ◽  
Vol 69 (12) ◽  
pp. 7493-7500 ◽  
Author(s):  
Dirk Bumann
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Antigen Expression ◽  
Cell Receptor ◽  
Cell Responses ◽  
Wide Range ◽  
Serovar Typhimurium ◽  
Cellular Immune

ABSTRACT Regulated antigen expression can influence the immunogenicity of live recombinant Salmonella vaccines, but a rational optimization has remained difficult since important aspects of this effect are incompletely understood. Here, attenuated Salmonella enterica serovar Typhimurium SL3261 strains expressing the model antigen GFP_OVA were used to quantify in vivo antigen levels by flow cytometry and to simultaneously follow the crucial early steps of antigen-specific T-cell responses in mice that are transgenic for a T-cell receptor recognizing ovalbumin. Among seven tested promoters,P pagC has the highest activity in murine tissues combined with low in vitro expression, whereasP tac has a comparable in vivo and a very high in vitro activity. Both SL3261 (pPpagCGFP_OVA) and SL3261 (pPtacGFP_OVA) cells can induce potent ovalbumin-specific cellular immune responses following oral administration, but doses almost 1,000-fold lower are sufficient for the in vivo-inducible construct SL3261 (pPpagCGFP_OVA) compared to SL3261 (pPtacGFP_OVA). This efficacy difference is largely explained by impaired early colonization capabilities of SL3261 (pPtacGFP_OVA) cells. Based on the findings of this study, appropriate in vivo expression levels for any given antigen can be rationally selected from the increasing set of promoters with defined properties. This will allow the improvement of recombinantSalmonella vaccines against a wide range of pathogens.

scholarly journals Functional analysis of peripheral and intratumoral neoantigen-specific TCRs identified in a patient with melanoma

2021 ◽  
Vol 9 (9) ◽  
pp. e002754
Author(s):  
Eva Bräunlein ◽  
Gaia Lupoli ◽  
Franziska Füchsl ◽  
Esam T Abualrous ◽  
Niklas de Andrade Krätzig ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Immune Checkpoint ◽  
T Cell Responses ◽  
Functional Avidity ◽  
Cell Responses

BackgroundNeoantigens derived from somatic mutations correlate with therapeutic responses mediated by treatment with immune checkpoint inhibitors. Neoantigens are therefore highly attractive targets for the development of therapeutic approaches in personalized medicine, although many aspects of their quality and associated immune responses are not yet well understood. In a case study of metastatic malignant melanoma, we aimed to perform an in-depth characterization of neoantigens and respective T-cell responses in the context of immune checkpoint modulation.MethodsThree neoantigens, which we identified either by immunopeptidomics or in silico prediction, were investigated using binding affinity analyses and structural simulations. We isolated seven T-cell receptors (TCRs) from the patient’s immune repertoire recognizing these antigens. TCRs were compared in vitro by multiparametric analyses including functional avidity, multicytokine secretion, and cross-reactivity screenings. A xenograft mouse model served to study in vivo functionality of selected TCRs. We investigated the patient’s TCR repertoire in blood and different tumor-related tissues over 3 years using TCR beta deep sequencing.ResultsSelected mutated peptide ligands with proven immunogenicity showed similar binding affinities to the human leukocyte antigen complex and comparable disparity to their wild-type counterparts in molecular dynamic simulations. Nevertheless, isolated TCRs recognizing these antigens demonstrated distinct patterns in functionality and frequency. TCRs with lower functional avidity showed at least equal antitumor immune responses in vivo. Moreover, they occurred at high frequencies and particularly demonstrated long-term persistence within tumor tissues, lymph nodes and various blood samples associated with a reduced activation pattern on primary in vitro stimulation.ConclusionsWe performed a so far unique fine characterization of neoantigen-specific T-cell responses revealing defined reactivity patterns of neoantigen-specific TCRs. Our data highlight qualitative differences of these TCRs associated with function and longevity of respective T cells. Such features need to be considered for further optimization of neoantigen targeting including adoptive T-cell therapies using TCR-transgenic T cells.

scholarly journals Spatial and temporal plasticity of neoantigen-specific T-cell responses bases on characteristics associated to antigen and TCR

2021 ◽  
Author(s):  
Eva Bräunlein ◽  
Gaia Lupoli ◽  
Esam T. Abualrous ◽  
Niklas de Andrade Krätzig ◽  
Dario Gosmann ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
T Cell Receptors ◽  
T Cell Responses ◽  
Tumor Rejection ◽  
Cell Receptors ◽  
Cell Responses

AbstractNeoantigens derived from somatic mutations have been demonstrated to correlate with therapeutic responses mediated by treatment with immune checkpoint inhibitors. Neoantigens are therefore highly attractive targets for the development of personalized medicine approaches although their quality and associated immune responses is not yet well understood. In a case study of metastatic malignant melanoma, we performed an in-depth characterization of neoantigens and respective T-cell responses in the context of immunotherapy with Ipilimumab. Three neoantigens identified either by immunopeptidomics or in silico prediction were investigated using binding affinity analyses and structural simulations. We isolated seven T-cell receptors (TCRs) from the patient immune repertoire recognizing these antigens. TCRs were compared in-vitro and in-vivo with multi-parametric analyses. Identified immunogenic peptides showed similar binding affinities to the human leukocyte antigen (HLA) complex and comparable differences to their wildtype counterparts in molecular dynamic simulations. Nevertheless, isolated TCRs differed substantially in functionality and frequency. In fact, TCRs with comparably lower functional avidity and higher potential for cross-reactivity provided at least equal anti-tumor immune responses in vivo. Of note, these TCRs showed a reduced activation pattern upon primary in vitro stimulation. Exploration of the TCR-β repertoire in blood and in different tumor-related tissues over three years, offered insights on the high frequency and particular long-term persistence of low-avidity TCRs. These data indicate that qualitative differences of neoantigen-specific TCRs and their impact on function and longevity need to be considered for neoantigen targeting by adoptive T-cell therapy using TCR-transgenic T cells.Statement of translational relevanceImmunotherapy has demonstrated high efficacy in diverse malignancies. Neoantigens derived from mutations provide promising targets for safe and highly tumor-specific therapeutic approaches. Yet, single determinants of an effective and enduring T-cell mediated tumor rejection are still not well understood. We analyzed in detail seven neoantigen-specific T-cell receptors (TCRs) derived from a melanoma patient targeting three different altered peptide ligands identified by mass spectrometry and prediction analyses. Functional characterization of these TCRs revealed potent anti-tumor reactivity of all TCRs. Of special interest, TCRs with comparably lower affinity demonstrated effective in vivo activity as well as dominant spatial and temporal distribution in blood and tissue. Functional differences of TCR may require further T-cell and/or TCR engineering and should be considered for future clinical trial designs.

scholarly journals Neutrophil subtypes shape HIV-specific CD8 T-cell responses after vaccinia virus infection

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Mauro Di Pilato ◽  
Miguel Palomino-Segura ◽  
Ernesto Mejías-Pérez ◽  
Carmen E. Gómez ◽  
Andrea Rubio-Ponce ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Vaccinia Virus ◽  
Adaptive Immune System ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Adaptive Immune

AbstractNeutrophils are innate immune cells involved in the elimination of pathogens and can also induce adaptive immune responses. Nα and Nβ neutrophils have been described with distinct in vitro capacity to generate antigen-specific CD8 T-cell responses. However, how these cell types exert their role in vivo and how manipulation of Nβ/Nα ratio influences vaccine-mediated immune responses are not known. In this study, we find that these neutrophil subtypes show distinct migratory and motility patterns and different ability to interact with CD8 T cells in the spleen following vaccinia virus (VACV) infection. Moreover, after analysis of adhesion, inflammatory, and migration markers, we observe that Nβ neutrophils overexpress the α4β1 integrin compared to Nα. Finally, by inhibiting α4β1 integrin, we increase the Nβ/Nα ratio and enhance CD8 T-cell responses to HIV VACV-delivered antigens. These findings provide significant advancements in the comprehension of neutrophil-based control of adaptive immune system and their relevance in vaccine design.

scholarly journals Optimized Adenovirus-Antibody Complexes Stimulate Strong Cellular and Humoral Immune Responses against an Encoded Antigen in Naïve Mice and Those with Preexisting Immunity

2011 ◽  
Vol 19 (1) ◽  
pp. 84-95 ◽  
Author(s):  
Jin Huk Choi ◽  
Joe Dekker ◽  
Stephen C. Schafer ◽  
Jobby John ◽  
Craig E. Whitfill ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Immune Responses ◽  
Neutralizing Antibodies ◽  
T Cell Responses ◽  
Transduction Efficiency ◽  
Virus Antibody ◽  
Cell Responses

ABSTRACTThe immune response to recombinant adenoviruses is the most significant impediment to their clinical use for immunization. We test the hypothesis that specific virus-antibody combinations dictate the type of immune response generated against the adenovirus and its transgene cassette under certain physiological conditions while minimizing vector-induced toxicity.In vitroandin vivoassays were used to characterize the transduction efficiency, the T and B cell responses to the encoded transgene, and the toxicity of 1 × 1011adenovirus particles mixed with different concentrations of neutralizing antibodies. Complexes formed at concentrations of 500 to 0.05 times the 50% neutralizing dose (ND50) elicited strong virus- and transgene-specific T cell responses. The 0.05-ND50formulation elicited measurable anti-transgene antibodies that were similar to those of virus alone (P= 0.07). This preparation also elicited very strong transgene-specific memory T cell responses (28.6 ± 5.2% proliferation versus 7.7 ± 1.4% for virus alone). Preexisting immunity significantly reduced all responses elicited by these formulations. Although lower concentrations (0.005 and 0.0005 ND50) of antibody did not improve cellular and humoral responses in naïve animals, they did promote strong cellular (0.005 ND50) and humoral (0.0005 ND50) responses in mice with preexisting immunity. Some virus-antibody complexes may improve the potency of adenovirus-based vaccines in naïve individuals, while others can sway the immune response in those with preexisting immunity. Additional studies with these and other virus-antibody ratios may be useful to predict and model the type of immune responses generated against a transgene in those with different levels of exposure to adenovirus.

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