Decision letter: The mucosal adjuvant cyclic di-GMP enhances antigen uptake and selectively activates pinocytosis-efficient cells in vivo

Effective mucosal adjuvants enhance the magnitude and quality of the vaccine response. Cyclic di-GMP (CDG) is a promising mucosal vaccine adjuvant. However, its in vivo mechanisms are unclear. Here, we showed, in mice, that CDG elicits stronger Ab and TH responses than the mammalian 2′3′-cyclic GMP-AMP (cGAMP), and generated better protection against Streptococcus pneumoniae infection than 2′3′-cGAMP adjuvanted vaccine. We identified two in vivo mechanisms of CDG. First, intranasally administered CDG greatly enhances Ag uptake, including pinocytosis and receptor-mediated endocytosis in vivo. The enhancement depends on MPYS (STING, MITA) expression in CD11C+ cells. Second, we found that CDG selectively activated pinocytosis-efficient-DCs, leading to TH polarizing cytokines IL-12p70, IFNγ, IL-5, IL-13, IL-23, and IL-6 production in vivo. Notably, CDG induces IFNλ, but not IFNβ, in vivo. Our study revealed previously unrecognized in vivo functions of MPYS and advanced our understanding of CDG as a mucosal vaccine adjuvant.

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Peyer's Patch Dendritic Cells Process Viral Antigen from Apoptotic Epithelial Cells in the Intestine of Reovirus-infected Mice

Journal of Experimental Medicine ◽

10.1084/jem.20041132 ◽

2004 ◽

Vol 200 (2) ◽

pp. 235-245 ◽

Cited By ~ 106

Author(s):

Marina N. Fleeton ◽

Nikhat Contractor ◽

Francisco Leon ◽

J. Denise Wetzel ◽

Terence S. Dermody ◽

...

Keyword(s):

T Cells ◽

Epithelial Cells ◽

Cd4 T Cells ◽

Cell Protein ◽

Peyer’S Patch ◽

Peyer's Patch ◽

Antigen Uptake ◽

Cross Presentation

We explored the role of Peyer's patch (PP) dendritic cell (DC) populations in the induction of immune responses to reovirus strain type 1 Lang (T1L). Immunofluorescence staining revealed the presence of T1L structural (σ1) and nonstructural (σNS) proteins in PPs of T1L-infected mice. Cells in the follicle-associated epithelium contained both σ1 and σNS, indicating productive viral replication. In contrast, σ1, but not σNS, was detected in the subepithelial dome (SED) in association with CD11c+/CD8α−/CD11blo DCs, suggesting antigen uptake by these DCs in the absence of infection. Consistent with this possibility, PP DCs purified from infected mice contained σ1, but not σNS, and PP DCs from uninfected mice could not be productively infected in vitro. Furthermore, σ1 protein in the SED was associated with fragmented DNA by terminal deoxy-UTP nick-end labeling staining, activated caspase-3, and the epithelial cell protein cytokeratin, suggesting that DCs capture T1L antigen from infected apoptotic epithelial cells. Finally, PP DCs from infected mice activated T1L-primed CD4+ T cells in vitro. These studies show that CD8α−/CD11blo DCs in the PP SED process T1L antigen from infected apoptotic epithelial cells for presentation to CD4+ T cells, and therefore demonstrate the cross-presentation of virally infected cells by DCs in vivo during a natural viral infection.

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Cell-Penetrating Peptide-Mediated Nanovaccine Delivery

Current Drug Targets ◽

10.2174/1389450122666210203193225 ◽

2021 ◽

Vol 22 ◽

Author(s):

Jizong Jiang

Keyword(s):

Immune System ◽

Immune Responses ◽

Cell Penetrating Peptide ◽

Antigen Delivery ◽

Efficient Manner ◽

Antigen Uptake ◽

Cell Penetrating ◽

The Stability ◽

Antigen Presenting

Abstract: Vaccination with small antigens, such as proteins, peptides, or nucleic acids, is used to activate the immune system and trigger the protective immune responses against a pathogen. Currently, nanovaccines are undergoing development instead of conventional vaccines. The size of nanovaccines is in the range of 10–500 nm, which enables them to be readily taken up by cells and exhibit improved safety profiles. However, low-level immune responses, as the removal of redundant pathogens, trigger counter-effective activation of the immune system invalidly and present a challenging obstacle to antigen recognition and its uptake via antigen-presenting cells (APCs). In addition, toxicity can be substantial. To overcome these problems, a variety of cell-penetrating peptide (CPP)-mediated vaccine delivery systems based on nanotechnology have been proposed, most of which are designed to improve the stability of antigens in vivo and their delivery into immune cells. CPPs are particularly attractive components of antigen delivery. Thus, the unique translocation property of CPPs ensures that they remain an attractive carrier with the capacity to deliver cargo in an efficient manner for the application of drugs, gene transfer, protein, and DNA/RNA vaccination delivery. CPP-mediated nanovaccines can enhance antigen uptake, processing, and presentation by APCs, which are the fundamental steps in initiating an immune response. This review describes the different types of CPP-based nanovaccines delivery strategies.

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DC subset–specific induction of T cell responses upon antigen uptake via Fcγ receptors in vivo

Journal of Experimental Medicine ◽

10.1084/jem.20160951 ◽

2017 ◽

Vol 214 (5) ◽

pp. 1509-1528 ◽

Cited By ~ 21

Author(s):

Christian H.K. Lehmann ◽

Anna Baranska ◽

Gordon F. Heidkamp ◽

Lukas Heger ◽

Kirsten Neubert ◽

...

Keyword(s):

T Cell ◽

T Cell Responses ◽

Cd8 T Cell ◽

Fcγ Receptors ◽

Specific Expression ◽

Antigen Uptake ◽

Surface Receptors ◽

Cell Responses ◽

Inflammatory Conditions

Dendritic cells (DCs) are efficient antigen-presenting cells equipped with various cell surface receptors for the direct or indirect recognition of pathogenic microorganisms. Interestingly, not much is known about the specific expression pattern and function of the individual activating and inhibitory Fcγ receptors (FcγRs) on splenic DC subsets in vivo and how they contribute to the initiation of T cell responses. By targeting antigens to select activating and the inhibitory FcγR in vivo, we show that antigen uptake under steady-state conditions results in a short-term expansion of antigen-specific T cells, whereas under inflammatory conditions especially, the activating FcγRIV is able to induce superior CD4+ and CD8+ T cell responses. Of note, this effect was independent of FcγR intrinsic activating signaling pathways. Moreover, despite the expression of FcγRIV on both conventional splenic DC subsets, the induction of CD8+ T cell responses was largely dependent on CD11c+CD8+ DCs, whereas CD11c+CD8− DCs were critical for priming CD4+ T cell responses.

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Essential Role of Host Double-Stranded DNA Released from Dying Cells by Cationic Liposomes for Mucosal Adjuvanticity

Vaccines ◽

10.3390/vaccines8010008 ◽

2019 ◽

Vol 8 (1) ◽

pp. 8

Author(s):

Rui Tada ◽

Akihiro Ohshima ◽

Yuya Tanazawa ◽

Akari Ohmi ◽

Saeko Takahashi ◽

...

Keyword(s):

Essential Role ◽

Cationic Liposome ◽

Cationic Liposomes ◽

Mucosal Vaccine ◽

Nasal Administration ◽

Adjuvant Activity ◽

Mucosal Adjuvant ◽

Double Stranded Dna ◽

Dying Cells

Infectious disease remains a substantial cause of death. To overcome this issue, mucosal vaccine systems are considered to be a promising strategy. Yet, none are approved for clinical use, except for live-attenuated mucosal vaccines, mainly owing to the lack of effective and safe systems to induce antigen-specific immune responses in the mucosal compartment. We have reported that intranasal vaccination of an antigenic protein, with cationic liposomes composed of 1,2-dioleoyl-3-trimethylammonium-propane and 3β-[N-(N′,N′-dimethylaminoethane)-carbamoyl], induced antigen-specific mucosal and systemic antibody responses in mice. However, precise molecular mechanism(s) underlying the mucosal adjuvant effects of cationic liposomes remain to be uncovered. Here, we show that a host double-stranded DNA (dsDNA), released at the site of cationic liposome injection, plays an essential role for the mucosal adjuvanticity of the cationic liposome. Namely, we found that nasal administration of the cationic liposomes induced localized cell death, at the site of injection, resulting in extracellular leakage of host dsDNA. Additionally, in vivo DNase I treatment markedly impaired OVA-specific mucosal and systemic antibody production exerted by cationic liposomes. Our report reveals that host dsDNA, released from local dying cells, acts as a damage-associated molecular pattern that mediates the mucosal adjuvant activity of cationic liposomes.

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Dendritic cell progenitors phagocytose particulates, including bacillus Calmette-Guerin organisms, and sensitize mice to mycobacterial antigens in vivo.

Journal of Experimental Medicine ◽

10.1084/jem.178.2.479 ◽

1993 ◽

Vol 178 (2) ◽

pp. 479-488 ◽

Cited By ~ 332

Author(s):

K Inaba ◽

M Inaba ◽

M Naito ◽

R M Steinman

Keyword(s):

T Cells ◽

Dendritic Cells ◽

Antigen Processing ◽

Blood Stream ◽

Active Immunization ◽

Bacillus Calmette Guerin ◽

Antigen Uptake ◽

Gm Csf ◽

Mycobacterial Antigens

Dendritic cells, while effective in sensitizing T cells to several different antigens, show little or no phagocytic activity. To the extent that endocytosis is required for antigen processing and presentation, it is not evident how dendritic cells would present particle-associated peptides. Evidence has now been obtained showing that progenitors to dendritic cells can internalize particles, including Bacillus Calmette-Guerin (BCG) mycobacteria. The particulates are applied for 20 h to bone marrow cultures that have been stimulated with granulocyte/macrophage colony-stimulating factor (GM-CSF) to induce aggregates of growing dendritic cells. Cells within these aggregates are clearly phagocytic. If the developing cultures are exposed to particles, washed, and "chased" for 2 d, the number of major histocompatibility complex class II-rich dendritic cells increases substantially and at least 50% contain internalized mycobacteria or latex particles. The mycobacteria-laden, newly developed dendritic cells are much more potent in presenting antigens to primed T cells than corresponding cultures of mature dendritic cells that are exposed to a pulse of organisms. A similar situation exists when the BCG-charged dendritic cells are injected into the footpad or blood stream of naive mice. Those dendritic cells that have phagocytosed organisms induce the strongest T cell responses to mycobacterial antigens in draining lymph node and spleen. The administration of antigens to GM-CSF-induced, developing dendritic cells (by increasing both antigen uptake and cell numbers) will facilitate the use of these antigen-presenting cells for active immunization in situ.

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Critical role of integrin CD11c in splenic dendritic cell capture of missing-self CD47 cells to induce adaptive immunity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1805542115 ◽

2018 ◽

Vol 115 (26) ◽

pp. 6786-6791 ◽

Cited By ~ 15

Author(s):

Jiaxi Wu ◽

Huaizhu Wu ◽

Jinping An ◽

Christie M. Ballantyne ◽

Jason G. Cyster

Keyword(s):

Critical Role ◽

T Cell Proliferation ◽

Cell Capture ◽

Antigen Uptake ◽

Cell Proliferation And Differentiation ◽

Proliferation And Differentiation ◽

Missing Self

CD11c, also known as integrin alpha X, is the most widely used defining marker for dendritic cells (DCs). CD11c can bind complement iC3b and mediate phagocytosis in vitro, for which it is also referred to as complement receptor 4. However, the functions of this prominent marker protein in DCs, especially in vivo, remain poorly defined. Here, in the process of studying DC activation and immune responses induced by cells lacking self-CD47, we found that DC capture of CD47-deficient cells and DC activation was dependent on the integrin-signaling adaptor Talin1. Specifically, CD11c and its partner Itgb2 were required for DC capture of CD47-deficient cells. CD11b was not necessary for this process but could partially compensate in the absence of CD11c. Mice with DCs lacking Talin1, Itgb2, or CD11c were defective in supporting T-cell proliferation and differentiation induced by CD47-deficient cell associated antigen. These findings establish a critical role for CD11c in DC antigen uptake and activation in vivo. They may also contribute to understanding the functional mechanism of CD47-blockade therapies.

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Glucocorticoids transform CD40-triggering of dendritic cells into an alternative activation pathway resulting in antigen-presenting cells that secrete IL-10

Blood ◽

10.1182/blood.v95.10.3162.010k18_3162_3167 ◽

2000 ◽

Vol 95 (10) ◽

pp. 3162-3167 ◽

Cited By ~ 6

Author(s):

Delphine Rea ◽

Cees van Kooten ◽

Krista E. van Meijgaarden ◽

Tom H. M. Ottenhoff ◽

Cornelis J. M. Melief ◽

...

Keyword(s):

T Cell ◽

T Cell Responses ◽

Alternative Activation ◽

Activation Process ◽

Th1 Cells ◽

T Helper 1 ◽

Antigen Uptake ◽

Cell Responses ◽

Cell Immunity

Dendritic cell (DC) activation through CD40-CD40 ligand interactions is a key regulatory step for the development of protective T-cell immunity and also plays an important role in the initiation of T-cell responses involved in autoimmune diseases and allograft rejection. In contrast to previous reports, we show that the immunosuppressive drug dexamethasone (DEX) redirects rather than simply blocks this DC activation process. We found that DCs triggered through CD40 in the presence of DEX were unable to acquire high levels of costimulatory, adhesion, and major histocompatibility complex class I and II molecules and failed to express the maturation marker CD83, whereas antigen uptake was not affected. Moreover, DEX strikingly modified the CD40-activated DC cytokine secretion profile by suppressing the production of the proinflammatory cytokine interleukin (IL)-12 and potentiating the secretion of the anti-inflammatory cytokine IL-10. Accordingly, DEX-exposed CD40-triggered DCs displayed a decreased T-cell allostimulatory potential and a dramatically impaired ability to activate cloned CD4+ T helper 1 (Th1) cells. Moreover, interaction between Th1 cells and these DCs rendered the T cells hyporesponsive to further antigen-specific restimulation. Collectively, our results demonstrate that DEX profoundly modulates CD40-dependent DC activation and suggest that the resulting alternatively activated DCs can be exploited for suppression of unwanted T-cell responses in vivo.

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