scholarly journals Optimize Prime/Boost Vaccine Strategies: Trained Immunity as a New Player in the Game

2021 ◽  
Vol 12 ◽  
Author(s):  
Jean-Louis Palgen ◽  
Yanis Feraoun ◽  
Gaëlle Dzangué-Tchoupou ◽  
Candie Joly ◽  
Frédéric Martinon ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Herd Immunity ◽  
Vaccine Dose ◽  
Secondary Memory ◽  
Full Potential ◽  
Antigen Uptake ◽  
Trained Immunity ◽  
Boost Vaccine ◽  
Sense And Respond

Most vaccines require multiple doses to induce long-lasting protective immunity in a high frequency of vaccines, and to ensure strong both individual and herd immunity. Repetitive immunogenic stimulations not only increase the intensity and durability of adaptive immunity, but also influence its quality. Several vaccine parameters are known to influence adaptive immune responses, including notably the number of immunizations, the delay between them, and the delivery sequence of different recombinant vaccine vectors. Furthermore, the initial effector innate immune response is key to activate and modulate B and T cell responses. Optimization of homologous and heterologous prime/boost vaccination strategies requires a thorough understanding of how vaccination history affects memory B and T cell characteristics. This requires deeper knowledge of how innate cells respond to multiple vaccine encounters. Here, we review how innate cells, more particularly those of the myeloid lineage, sense and respond differently to a 1st and a 2nd vaccine dose, both in an extrinsic and intrinsic manner. On one hand, the presence of primary specific antibodies and memory T cells, whose critical properties change with time after priming, provides a distinct environment for innate cells at the time of re-vaccination. On the other hand, innate cells themselves can exert enhanced intrinsic antimicrobial functions, long after initial stimulation, which is referred to as trained immunity. We discuss the potential of trained innate cells to be game-changers in prime/boost vaccine strategies. Their increased functionality in antigen uptake, antigen presentation, migration, and as cytokine producers, could indeed improve the restimulation of primary memory B and T cells and their differentiation into potent secondary memory cells in response to the boost. A better understanding of trained immunity mechanisms will be highly valuable for harnessing the full potential of trained innate cells, to optimize immunization strategies.

scholarly journals Methotrexate enhances antigen presentation and maturation of tumour antigen-loaded dendritic cells through NLRP3 inflammasome activation: a strategy for dendritic cell-based cancer vaccine

2021 ◽  
Vol 13 ◽  
pp. 175883592098705
Author(s):  
Gao-Na Shi ◽  
Min Hu ◽  
Chengjuan Chen ◽  
Junmin Fu ◽  
Shuai Shao ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
Nlrp3 Inflammasome ◽  
Tumour Antigen ◽  
Inflammasome Activation ◽  
Antigen Uptake ◽  
Nlrp3 Inflammasome Activation ◽  
Dc Maturation

Background: Dendritic cells (DCs) are antigen-presenting cells that play a pivotal role in adaptive cell-mediated immunity by priming and activating T cells against specific tumour and pathogenic antigens. Methotrexate (MTX), a folate derivative, functions as an immunoregulatory agent. However, the possible effect of MTX on tumour antigen-loaded DCs has not yet been investigated. Methods: We analysed the effect of MTX on the maturation and function of DCs along with tumour cell lysates (TCLs). Using bone marrow-derived DCs, we investigated the effect of MTX combined TCL-loaded DCs on T cells priming and proliferation. We also tested the anti-tumour immune effect on DCs when treated with MTX and/or TCL in vivo. Results: MTX combined with TCL not only enhanced DC maturation and stimulated cytokine release but also promoted CD8+ T cell activation and proliferation. The latter was associated with increased tumour antigen uptake and cross-presentation to T cells. Mechanistically, DC maturation and antigen presentation were partly modulated by NLRP3 inflammasome activation. Furthermore, immunisation of mice with MTX and TCL-pulsed DCs before a tumour challenge significantly delayed tumour onset and retarded its growth. This protective effect was due to priming of IFN-γ releasing CD8+ T cells and enhanced killing of tumour cells by cytotoxic T lymphocytes isolated from these immunised mice. Conclusion: MTX can function as a potent adjuvant in DC vaccines by increasing antigen presentation and T cell priming. Our findings provide a new strategy for the application of DC-based anti-tumour immunotherapy.

scholarly journals Activation Outcomes Induced in Naïve CD8 T-Cells by Macrophages Primed via “Phagocytic” and Nonphagocytic Pathways

2008 ◽  
Vol 19 (2) ◽  
pp. 701-710 ◽  
Author(s):  
Isabel María Olazabal ◽  
Noa Beatriz Martín-Cofreces ◽  
María Mittelbrunn ◽  
Gloria Martínez del Hoyo ◽  
Balbino Alarcón ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
T Cell Proliferation ◽  
Microtubule Organizing Center ◽  
Antigen Uptake ◽  
Soluble Peptide

The array of phagocytic receptors expressed by macrophages make them very efficient at pathogen clearance, and the phagocytic process links innate with adaptive immunity. Primary macrophages modulate antigen cross-presentation and T-cell activation. We assessed ex vivo the putative role of different phagocytic receptors in immune synapse formation with CD8 naïve T-cells from OT-I transgenic mice and compared this with the administration of antigen as a soluble peptide. Macrophages that have phagocytosed antigen induce T-cell microtubule-organizing center and F-actin cytoskeleton relocalization to the contact site, as well as the recruitment of proximal T-cell receptor signals such as activated Vav1 and PKCθ. At the same doses of loaded antigen (1 μM), “phagocytic” macrophages were more efficient than peptide-antigen–loaded macrophages at forming productive immune synapses with T-cells, as indicated by active T-cell TCR/CD3 conformation, LAT phosphorylation, IL-2 production, and T-cell proliferation. Similar T-cell proliferation efficiency was obtained when low doses of soluble peptide (3–30 nM) were loaded on macrophages. These results suggest that the pathway used for antigen uptake may modulate the antigen density presented on MHC-I, resulting in different signals induced in naïve CD8 T-cells, leading either to CD8 T-cell activation or anergy.

scholarly journals Nanoconfinement of Microvilli Alters Gene Expression and Boosts T cell Activation

2021 ◽  
Author(s):  
Morteza Aramesh ◽  
Diana Stoycheva ◽  
Ioana Sandu ◽  
Stephan J. Ihle ◽  
Tamara Zund ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
Cell Signaling ◽  
T Cell Activation ◽  
Cell Activation ◽  
Local Environment ◽  
T Cell Signaling ◽  
Sense And Respond ◽  
Altered Gene

T cells sense and respond to their local environment at the nanoscale by forming small actin-rich protrusions, called microvilli, which play critical roles in signaling and antigen recognition, particularly at the interface with the antigen presenting cells. However, the mechanisms by which microvilli contribute to cell signaling and activation is largely unknown. Here, we present a tunable engineered system that promotes microvilli formation and T cell signaling via physical stimuli. We discovered that nanoporous surfaces favored microvilli formation, and markedly altered gene expression in T cells and promoted their activation. Mechanistically, confinement of microvilli inside of nanopores leads to size-dependent sorting of membrane-anchored proteins, specifically segregating CD45 phosphatases and T cell receptors (TCR) from the tip of the protrusions when microvilli are confined in 200 nm pores, but not in 400 nm pores. Consequently, formation of TCR nanoclustered hotspots within 200 nm pores, allows sustained and augmented signaling that prompts T cell activation even in the absence of TCR agonists. The synergistic combination of mechanical and biochemical signals on porous surfaces presents a straightforward strategy to investigate the role of microvilli in T cell signaling as well as to boost T cell activation and expansion for application in the growing field of adoptive immunotherapy.

scholarly journals Baseline Levels of Influenza-Specific B Cells and T Cell Responses Modulate Human Immune Responses to Swine Variant Influenza A/H3N2 Vaccine

Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 126
Author(s):  
Lilin Lai ◽  
Nadine Rouphael ◽  
Yongxian Xu ◽  
Amy C. Sherman ◽  
Srilatha Edupuganti ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Influenza A ◽  
Vaccine Dose ◽  
T Cell Responses ◽  
Post Vaccination ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Cellular Immune

The cellular immune responses elicited by an investigational vaccine against an emergent variant of influenza (H3N2v) are not fully understood. Twenty-five subjects, enrolled in an investigational influenza A/H3N2v vaccine study, who received two doses of vaccine 21 days apart, were included in a sub-study of cellular immune responses. H3N2v-specific plasmablasts were determined by ELISpot 8 days after each vaccine dose and H3N2v specific CD4+ T cells were quantified by intracellular cytokine and CD154 (CD40 ligand) staining before vaccination, 8 and 21 days after each vaccine dose. Results: 95% (19/20) and 96% (24/25) subjects had pre-existing H3N2v specific memory B, and T cell responses, respectively. Plasmablast responses at Day 8 after the first vaccine administration were detected against contemporary H3N2 strains and correlated with hemagglutination inhibition HAI (IgG: p = 0.018; IgA: p < 0.001) and Neut (IgG: p = 0.038; IgA: p = 0.021) titers and with memory B cell frequency at baseline (IgA: r = 0.76, p < 0.001; IgG: r = 0.74, p = 0.0001). The CD4+ T cells at Days 8 and 21 expanded after prime vaccination and this expansion correlated strongly with early post-vaccination HAI and Neut titers (p ≤ 0.002). In an adult population, the rapid serological response observed after initial H3N2v vaccination correlates with post-vaccination plasmablasts and CD4+ T cell responses.

scholarly journals Distinct populations of dendritic cells are present in the subepithelial dome and T cell regions of the murine Peyer's patch.

1996 ◽  
Vol 183 (1) ◽  
pp. 237-247 ◽  
Author(s):  
B L Kelsall ◽  
W Strober
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cd8 T Cells ◽  
Germinal Center ◽  
Cell Receptor ◽  
Dense Layer ◽  
Peyer’S Patch ◽  
Peyer's Patch ◽  
Antigen Uptake

Despite the fact that the Peyer's patch (PP) is the primary site for antigen uptake in the intestine, the cellular basis of antigen handling after transport into the PP is poorly understood. We performed immunohistology of murine PPs using the dendritic cell (DC)-reactive monoclonal antibodies N418, NLDC-145, M342, and 2A1, as well as antibodies to other T cell, B cell, and macrophage markers. N418+, 2A1+, NLDC-145-, M342- cells form a dense layer of cells in the subepithelial dome (SED), just beneath the follicle epithelium, and are scattered throughout the follicle, sparing the germinal center. In contrast, N418+, 2A1+, NLDC-145+, and M342+ DCs are present in the interfollicular T cell regions (IFR). CD3+ and CD4+, but no CD8+ T cells were present in the SED and the follicle, including the germinal center, while CD3+, CD4+, and CD8+ T cells were present in the IFR. B cells and macrophages were poorly represented in the SED as no B220+ cells, only few Mac-1lo cells, and no F4/80+ cells were present at this site. In contrast, Mac-1hi cells were found in the IFR and lamina propria of intestinal villi, while F4/80+ cells were found only in the latter. In further phenotypic studies, we analyzed surface molecules of PP and spleen DCs by flow cytometry and found that these cells had similar fluorescence profiles when stained with N418, NLDC-145, and 33D1 DC-reactive antibodies, and antibodies to the costimulatory molecules B7-1 (1G10) and B7-2 (GL1). In contrast, PP DCs expressed 5-10-fold higher levels of major histocompatibility complex class II antigens (IEk) than spleen DCs. Finally, in functional studies, we demonstrated that both PP and spleen DCs process soluble protein antigens during overnight culture and induce similar levels of proliferation in CD3+ T cells, and CD4+/Mel 14hi T cells from T cell receptor transgenic mice. The in vivo relevance of such presentation was shown by the fact that PP DCs isolated from Balb/c mice after being fed ovalbumin stimulated proliferation in ovalbumin T cell receptor T cells. Taken together, our data suggest that DCs in the SED of the PP are uniquely positioned for the processing of antigens passed into the PP from the overlying M cell, and that PP DCs are effective at processing and presenting oral antigens to naive T cells.

Imiquimod: A TLR-7 agonist as adjuvant for a recombinant protein cancer vaccine

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 8545-8545
Author(s):  
S. Adams ◽  
D. O'Neill ◽  
D. Nonaka ◽  
O. Manches ◽  
L. Chiriboga ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Intracellular Cytokine Staining ◽  
T Cell Responses ◽  
Protein Vaccine ◽  
Imiquimod Cream ◽  
Antigen Uptake ◽  
Cell Responses ◽  
Cell Immunity

8545 Purpose: This clinical trial evaluates the safety and adjuvant activity of imiquimod, a toll-like receptor (TLR)-7 agonist, when given with a NY-ESO-1 protein vaccine. Imiquimod, by locally activating and recruiting dendritic cells (DCs) into the skin, is expected to stimulate antigen uptake by DCs, induce maturation and migration to draining lymph nodes, and to induce antigen-specific T and B cell immunity. Methods: Pilot study; 9 patients with resected stage 2B-3C malignant melanoma. Four 21 day cycles consisted of topical imiquimod cream (250 mg) on days 1–5 and id. injected NY-ESO-1 protein (100 mcg) into the site on day 3. Blood was drawn at several time points for immune monitoring; skin punch biopsies were obtained from control, imiquimod and vaccination sites 48 hours after the last vaccination. Results: The regimen was tolerated well, all patients completed four vaccinations. AEs were mild and transient and included injection site reactions (8/9 patients), fatigue (4/9 patients) and fever (2/9 patients). Significant levels of antigen-specific CD4+ or CD8+ T cell responses were not detected in ex-vivo ELISPOT assays. However, intracellular cytokine staining assays after in vitro pre-stimulation indicated that 6 of 8 subjects developed NY-ESO-1 CD4+ T cell responses. Humoral immunity was manifest by the induction of anti-NY-ESO-1 antibodies in 7/9 patients post-vaccination. Histochemistry of skin sections showed significant dermal mononuclear cell infiltrates in Imiquimod treated skin, whereas none were seen in untreated skin (p<0.01). IHC revealed markedly increased numbers of CD3+ (T-cells), CD68+ (macrophages/monocytes), CD123+ (plasmacytoid DCs) and DC-LAMP+ (mature myeloid DCs) immune cells in Imiquimod treated skin when compared with control skin of the same patients (p<0.05). Conclusion: Imiquimod, a topical immune response modifier, generated clear inflammatory infiltrates in the dermis, with significant increases in antigen-presenting cells and T cells. Imiquimod was well tolerated when used as an adjuvant to an NY-ESO-1 protein vaccine. Systemic immunity of both humoral and cellular types was induced in the majority of patients; however, responses were weak and the vaccine combination needs to be optimized in future studies. No significant financial relationships to disclose.

scholarly journals Preexisting Inflammation Due to Mycobacterium bovis BCG Infection Differentially Modulates T-Cell Priming against a Replicating or Nonreplicating Immunogen

2002 ◽  
Vol 70 (4) ◽  
pp. 1957-1964 ◽  
Author(s):  
Renu Dudani ◽  
Yvan Chapdelaine ◽  
Henk van Faassen ◽  
Dean K. Smith ◽  
Hao Shen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mycobacterium Bovis ◽  
Inflammatory Responses ◽  
Protective Efficacy ◽  
T Cell Response ◽  
Boost Vaccine ◽  
Ifn Γ ◽  
T Cell Priming

ABSTRACT Induction of T-cell memory by vaccination ensures long-term protection against pathogens. We determined whether on-going inflammatory responses during vaccination influenced T-cell priming. A preexposure of mice to Mycobacterium bovis BCG impaired their subsequent ability to prime T cells against Listeria monocytogenes. This was characterized by a decrease in L. monocytogenes-specific gamma interferon (IFN-γ)-secreting CD4+ and CD8+ T cells. The intensity of T-cell priming towards L. monocytogenes depended on the extent of L. monocytogenes expansion, and a cessation of this expansion caused by M. bovis BCG-induced inflammation resulted in impairment in T-cell priming. A challenge of M. bovis BCG-infected mice with a higher L. monocytogenes dose increased L. monocytogenes survival and restored T-cell priming towards L. monocytogenes. Impairment in T-cell priming towards L. monocytogenes due to M. bovis BCG-induced inflammation resulted in a compromised protective efficacy in the long term after mice were rechallenged with L. monocytogenes. Preexisting inflammation selectively impaired T-cell priming for replicating immunogens as CD8+ T-cell response to ovalbumin administered as an inert antigen (ovalbumin-archaeosomes) was enhanced by M. bovis BCG preimmunization, whereas priming towards ovalbumin administered as a live immunogen (L. monocytogenes-ovalbumin) was impaired. Thus, depending on the nature of the immunogen, the presence of prior inflammatory responses may either impede or boost vaccine efficacy.

scholarly journals The Effects of Trained Innate Immunity on T Cell Responses; Clinical Implications and Knowledge Gaps for Future Research

2021 ◽  
Vol 12 ◽  
Author(s):  
Dearbhla M. Murphy ◽  
Kingston H. G. Mills ◽  
Sharee A. Basdeo
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Cells ◽  
T Cell Responses ◽  
Innate Immune ◽  
Metabolic Reprogramming ◽  
Innate Immune Cells ◽  
Peripheral Tissues ◽  
Trained Immunity ◽  
Cell Responses

The burgeoning field of innate immune training, also called trained immunity, has given immunologists new insights into the role of innate responses in protection against infection and in modulating inflammation. Moreover, it has led to a paradigm shift in the way we think about immune memory and the interplay between innate and adaptive immune systems in conferring immunity against pathogens. Trained immunity is the term used to describe the medium-term epigenetic and metabolic reprogramming of innate immune cells in peripheral tissues or in the bone marrow stem cell niche. It is elicited by an initial challenge, followed by a significant period of rest that results in an altered response to a subsequent, unrelated challenge. Trained immunity can be associated with increased production of proinflammatory mediators, such as IL-1β, TNF and IL-6, and increased expression of markers on innate immune cells associated with antigen presentation to T cells. The microenvironment created by trained innate immune cells during the secondary challenge may have profound effects on T cell responses, such as altering the differentiation, polarisation and function of T cell subtypes, including Th17 cells. In addition, the Th1 cytokine IFN-γ plays a critical role in establishing trained immunity. In this review, we discuss the evidence that trained immunity impacts on or can be impacted by T cells. Understanding the interplay between innate immune training and how it effects adaptive immunity will give insights into how this phenomenon may affect the development or progression of disease and how it could be exploited for therapeutic interventions or to enhance vaccine efficacy.

scholarly journals mRNA vaccine-induced SARS-CoV-2-specific T cells recognize B.1.1.7 and B.1.351 variants but differ in longevity and homing properties depending on prior infection status

2021 ◽  
Author(s):  
Jason Neidleman ◽  
Xiaoyu Luo ◽  
Matthew McGregor ◽  
Guorui Xie ◽  
Victoria Murray ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Response ◽  
Vaccine Dose ◽  
T Cell Response ◽  
Immune Defense ◽  
Cell Numbers ◽  
Prior Infection

While mRNA vaccines are proving highly efficacious against SARS-CoV-2, it is important to determine how booster doses and prior infection influence the immune defense they elicit, and whether they protect against variants. Focusing on the T cell response, we conducted a longitudinal study of infection-naive and COVID-19 convalescent donors before vaccination and after their first and second vaccine doses, using a high-parameter CyTOF analysis to phenotype their SARS-CoV-2-specific T cells. Vaccine-elicited spike-specific T cells responded similarly to stimulation by spike epitopes from the ancestral, B.1.1.7 and B.1.351 variant strains, both in terms of cell numbers and phenotypes. In infection-naive individuals, the second dose boosted the quantity but not quality of the T cell response, while in convalescents the second dose helped neither. Spike-specific T cells from convalescent vaccinees differed strikingly from those of infection-naive vaccinees, with phenotypic features suggesting superior long-term persistence and ability to home to the respiratory tract including the nasopharynx. These results provide reassurance that vaccine-elicited T cells respond robustly to the B.1.1.7 and B.1.351 variants, confirm that convalescents may not need a second vaccine dose, and suggest that vaccinated convalescents may have more persistent nasopharynx-homing SARS-CoV-2-specific T cells compared to their infection-naive counterparts.

scholarly journals Designing Strategies to Improve the T Cell  Mediated Immunotherapy of Mouse Tumours.

2021 ◽  
Author(s):  
◽  
Haley Ataera
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Tumour Response ◽  
T Cell Responses ◽  
T Cell Response ◽  
Full Potential ◽  
Activation Markers ◽  
Cell Responses

<p>The adoptive transfer of activated dendritic cells (DC) loaded with tumour antigen or tumour specific T cells improves weak anti-tumour responses, however, without treatments to relieve suppression, these therapies will continue to fall short of their full potential. The aim of this thesis was to understand the role of hypoxia-induced increases in adenosine and of CD4+ CD25+ Foxp3+ regulatory T cells (Treg) in the suppression of anti-tumour immune responses and to design strategies to abrogate these mechanisms. These aims were investigated using the B16.OVA murine melanoma model because the OVA specific CD4+ (OTII) and CD8+ (OTI) T cell transgenic mice allowed detailed investigation of Ag specific T cell responses. Recent studies have shown that the inhibition of adenosine signalling in activated CD8+ T cells can improve the anti-tumour activity of these cells. To investigate these findings using the B16.OVA model, tumour-bearing mice were given activated OTI T cells and the adenosine receptor inhibitor caffeine. Caffeine treatment did not improve the anti-tumour response, possibly because this response was suppressed due to the increased frequency of myeloid derived suppressor cells observed in mice that received T cells. To determine whether the defective function of tumour infiltrating DC (TIDC) in tumours is due to suppression by Treg, mice were treated with the anti-CD25 monoclonal antibody PC61 to deplete Treg and challenged with tumours. PC61 treatment caused a delay in tumour growth but did not affect DC frequency, or expression of the DC activation markers CD40, CD86 and MHC II in tumours or lymph nodes. DC function was tested using in vitro and in vivo T cell proliferation assays and was found to be unaffected by PC61 treatment. Studies in RAG1-/- mice, which lack Treg, also showed no improvement in DC activation status or function. These results show that Treg do not suppress TIDC in the B16.OVA model. It is well known, however, that Treg suppress T cell responses and it has been suggested that Treg may mediate some of this suppression by using the perforin-granzyme pathway to cause T cell death. To investigate this possibility, naive, perforin sufficient OTI T cells were transferred into normal and perforin knockout (PKO) mice, with or without PC61 treatment. To stimulate an OTI T cell response, mice also received OVA-loaded DC. Depletion of both normal and PKO Treg resulted in decreased death and increased proliferation of the transferred cells, increased expression of IFN-y and TNF-a, and improved in vivo target cell killing by the transferred cells. These findings indicate that perforin expression by Treg is not required to suppress T cell responses or cause T cell death. In conclusion, the results of this thesis were consistent with the observation that there are multiple suppressive mechanisms in tumours and that there is substantial redundancy of these mechanisms. Depletion of Treg was found to improve the anti-tumour response, however, suppression of the DC was still evident, demonstrating that the neutralisation of a single suppressive mechanism may not be sufficient to treat aggressive, late stage cancers such as melanoma.</p>

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