scholarly journals Staphylococcus aureus-Specific Tissue-Resident Memory CD4+ T Cells Are Abundant in Healthy Human Skin

2021 ◽  
Vol 12 ◽  
Author(s):  
Astrid Hendriks ◽  
Malgorzata Ewa Mnich ◽  
Bruna Clemente ◽  
Ana Rita Cruz ◽  
Simona Tavarini ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
T Cells ◽  
Human Skin ◽  
Ex Vivo ◽  
Functional Characterization ◽  
T Cell Response ◽  
Skin Microbiome ◽  
Entry Site ◽  
Healthy Human ◽  
Skin Explants

The skin is an immunocompetent tissue that harbors several kinds of immune cells and a plethora of commensal microbes constituting the skin microbiome. Staphylococcus aureus is a prominent skin pathogen that colonizes a large proportion of the human population. We currently have an incomplete understanding of the correlates of protection against S. aureus infection, however genetic and experimental evidence has shown that CD4+ T cells play a key role in orchestrating a protective anti-S. aureus immune response. A high S. aureus-specific memory CD4+ T cell response has been reported in the blood of healthy subjects. Since T cells are more abundant in the skin than in blood, we hypothesized that S. aureus-specific CD4+ T cells could be present in the skin of healthy individuals. Indeed, we observed proliferation of tissue-resident memory CD4+ T cells and production of IL-17A, IL-22, IFN-γ and TNF-β by cells isolated from abdominal skin explants in response to heat-killed S. aureus. Remarkably, these cytokines were produced also during an ex vivo epicutaneous S. aureus infection of human skin explants. These findings highlight the importance of tissue-resident memory CD4+ T cells present at barrier sites such as the skin, a primary entry site for S. aureus. Further phenotypical and functional characterization of these cells will ultimately aid in the development of novel vaccine strategies against this elusive pathogen.

scholarly journals Adaptation of Staphylococcus aureus to the Human Skin Environment Identified Using an ex vivo Tissue Model

2021 ◽  
Vol 12 ◽  
Author(s):  
Marc Burian ◽  
Johanna Plange ◽  
Laurenz Schmitt ◽  
Anke Kaschke ◽  
Yvonne Marquardt ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Human Skin ◽  
Target Genes ◽  
Ex Vivo ◽  
Teichoic Acid ◽  
Regulatory Elements ◽  
Initial Contact ◽  
Wall Teichoic Acid ◽  
Healthy Human ◽  
Skin Contact

The healthy human epidermis provides physical protection and is impenetrable for pathogenic microbes. Nevertheless, commensal and pathogen bacteria such as Staphylococcus aureus are able to colonize the skin surface, which may subsequently lead to infection. To identify and characterize regulatory elements facilitating adaptation of S. aureus to the human skin environment we used ex vivo tissue explants and quantified S. aureus gene transcription during co-culture. This analysis provided evidence for a significant downregulation of the global virulence regulator agr upon initial contact with skin, regardless of the growth phase of S. aureus prior to co-culture. In contrast, the alternative sigma factor B (sigB) and the antimicrobial peptide-sensing system (graRS) were expressed during early colonization. Consistently, sigB target genes such as the clumping factor A (clfA) and fibrinogen and fibronectin binding protein A (fnbA) were strongly upregulated upon skin contact. At later timepoints of the adhesion process, wall teichoic acid (WTA) synthesis was induced. Besides the expression of adhesive molecules, transcription of molecules involved in immune evasion were increased during late colonization (staphylococcal complement inhibitor and staphylokinase). Similar to nasal colonization, enzymes involved in cell wall metabolism (sceD and atlA) were highly transcribed. Finally, we detected a strong expression of proteases from all three catalytic classes during the entire colonization process. Taken together, we here present an ex vivo skin colonization model that allows the detailed characterization of the bacterial adaptation to the skin environment.

scholarly journals Checkpoint blockade accelerates a novel switch from an NKT-driven TNFα response toward a T cell driven IFN-γ response within the tumor microenvironment

2021 ◽  
Vol 9 (6) ◽  
pp. e002269
Author(s):  
Shota Aoyama ◽  
Ryosuke Nakagawa ◽  
Satoshi Nemoto ◽  
Patricio Perez-Villarroel ◽  
James J Mulé ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Ex Vivo ◽  
T Cell Response ◽  
Effector Function ◽  
Checkpoint Blockade ◽  
Necrosis Factor Alpha ◽  
Ifn Γ

BackgroundThe temporal response to checkpoint blockade (CB) is incompletely understood. Here, we profiled the tumor infiltrating lymphocyte (TIL) landscape in response to combination checkpoint blockade at two distinct timepoints of solid tumor growth.MethodsC57BL/6 mice bearing subcutaneous MC38 tumors were treated with anti-PD-1 and/or anti-CTLA-4 antibodies. At 11 or 21 days, TIL phenotype and effector function were analyzed in excised tumor digests using high parameter flow cytometry. The contributions of major TIL populations toward overall response were then assessed using ex vivo cytotoxicity and in vivo tumor growth assays.ResultsThe distribution and effector function among 37 distinct TIL populations shifted dramatically between early and late MC38 growth. At 11 days, the immune response was dominated by Tumor necrosis factor alpha (TNFα)-producing NKT, representing over half of all TIL. These were accompanied by modest frequencies of natural killer (NK), CD4+, or CD8+ T cells, producing low levels of IFN-γ. At 21 days, NKT populations were reduced to a combined 20% of TIL, giving way to increased NK, CD4+, and CD8+ T cells, with increased IFN-γ production. Treatment with CB accelerated this switch. At day 11, CB reduced NKT to less than 20% of all TIL, downregulated TNFα across NKT and CD4+ T cell populations, increased CD4+ and CD8+ TIL frequencies, and significantly upregulated IFN-γ production. Degranulation was largely associated with NK and NKT TIL. Blockade of H-2kb and/or CD1d during ex vivo cytotoxicity assays revealed NKT has limited direct cytotoxicity against parent MC38. However, forced CD1d overexpression in MC38 cells significantly diminished tumor growth, suggesting NKT TIL exerts indirect control over MC38 growth.ConclusionsDespite an indirect benefit of early NKT activity, CB accelerates a switch from TNFα, NKT-driven immune response toward an IFN-γ driven CD4+/CD8+ T cell response in MC38 tumors. These results uncover a novel NKT/T cell switch that may be a key feature of CB response in CD1d+ tumors.

scholarly journals HIV-1 Selection by Epidermal Dendritic Cells during Transmission across Human Skin

1998 ◽  
Vol 187 (10) ◽  
pp. 1623-1631 ◽  
Author(s):  
Jeanette C. Reece ◽  
Amanda J. Handley ◽  
E. John Anstee ◽  
Wayne A. Morrison ◽  
Suzanne M. Crowe ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Human Skin ◽  
Cell Sorting ◽  
Virus Entry ◽  
Skin Explants ◽  
Skin Uptake ◽  
Virus Exposure ◽  
Epidermal Dendritic Cells ◽  
Hiv 1

Macrophage tropic HIV-1 is predominant during the initial viremia after person to person transmission of HIV-1 (Zhu, T., H. Mo, N. Wang, D.S. Nam, Y. Cao, R.A. Koup, and D.D. Ho. 1993. Science. 261:1179–1181.), and this selection may occur during virus entry and carriage to the lymphoid tissue. Human skin explants were used to model HIV-1 selection that may occur at the skin or mucosal surface. Macrophage tropic, but not T cell line tropic strains of HIV-1 applied to the abraded epidermis were recovered from the cells emigrating from the skin explants. Dermis and epidermis were separated by dispase digestion after virus exposure to determine the site of viral selection within the skin. Uptake and transmission to T cells of all HIV-1 isolates was found with the dermal emigrant cells, but only macrophage tropic virus was transferred by emigrants from the epidermis exposed to HIV-1, indicating selection only within the epidermis. CD3+, CD4+ T cells were found in both the dermal and epidermal emigrant cells. After cell sorting to exclude contaminating T cells, macrophage tropic HIV-1 was found in both the dermal emigrant dendritic cells and in dendritic cells sorted from the epidermal emigrants. These observations suggest that selective infection of the immature epidermal dendritic cells represents the cellular mechanism that limits the initial viremia to HIV-1 that can use the CCR5 coreceptor.

scholarly journals ID3024 Polymeric nanoparticles display bactericidal effect and selective fermentation for the treatment of acne vulgaris

2017 ◽  
Vol 4 (S) ◽  
pp. 34
Author(s):  
Ming-Fa Hsieh
Keyword(s):  
Human Skin ◽  
Ex Vivo ◽  
Polymeric Nanoparticles ◽  
Acne Vulgaris ◽  
Short Chain Fatty Acids ◽  
Bactericidal Effect ◽  
Skin Microbiome ◽  
Poly Ethylene Glycol ◽  
Effective Doses ◽  
Poly Ethylene

The use of antibiotics in the treatment of acne in specific group (pregnant women) of patients can lead to serious complications. We have previously demonstrated that the nanoparticles made of block copolymers of poly (ethylene glycol) and poly(e-caprolactone) can inhibit the growth of Propionibacterium acnes (P. acnes), a bacterium highly associated with the progress of acne vulgaris in the human skin [Polymers 2016; 8, 321]. To reduce the amount of antibiotics used in the treatment of skin acne, we have further demonstrated that a bacterium in the human skin microbiome can utilize PEG-based polymers to produce various short-chain fatty acids (SCFAs) which suppressed the growth of P. acnes. PEG-based polymers were chosen as selective fermentation initiators which specifically induced the fermentation of the skin commensal bacterium but not P. acnes. Interestingly, PEG-based polymers can efficiently suppress the growth of P. acnes. An acne ex vivo explant was established by using acne biopsies collected from patients with acne vulgaris at the early and middle stages. The levels of pro-inflammatory interleukin (IL)-8 cytokine in early- and middle-staged acnes were significantly higher than those in healthy skins. Incubation of acne ex vivo explants with sucrose remarkably reduced the level of IL-8 and the number of P. acnes. Results from mouse studies revealed that PEG-based polymer functions as antibiotic adjuvants which can considerably reduce the effective doses of clindamycin, a clinically-used acne antibiotic

scholarly journals Pharmacokinetics and Pharmacodynamics of Levofloxacin against Streptococcus pneumoniae and Staphylococcus aureus in Human Skin Blister Fluid

2000 ◽  
Vol 44 (5) ◽  
pp. 1352-1355 ◽  
Author(s):  
Andrej Trampuz ◽  
Markus Wenk ◽  
Zarko Rajacic ◽  
Werner Zimmerli
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Oral Dose ◽  
Human Skin ◽  
Bactericidal Activity ◽  
Ex Vivo ◽  
Blister Fluid ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Skin Blister ◽  
And Staphylococcus Aureus

ABSTRACT The pharmacokinetics of levofloxacin in serum and in skin blister fluid (SBF) was determined for 20 volunteers after a single 500-mg oral dose of levofloxacin. In addition, ex vivo bactericidal activity of SBF against Streptococcus pneumoniae and Staphylococcus aureus was studied. SBF containing levofloxacin and granulocytes killed 5.2 log of Streptococcus pneumoniae bacteria and 2.0 log of Staphylococcus aureus bacteria during a 6-h incubation.

Cutaneous DNA delivery and gene expression in ex vivo human skin explants via wet-etch microfabricated microneedles

2005 ◽  
Vol 13 (7) ◽  
pp. 415-421 ◽  
Author(s):  
James Birchall ◽  
Sion Coulman ◽  
Marc Pearton ◽  
Chris Allender ◽  
Keith Brain ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Skin ◽  
Ex Vivo ◽  
Dna Delivery ◽  
Skin Explants ◽  
Wet Etch

scholarly journals Dendritic cells transduced by multiply deleted HIV-1 vectors exhibit normal phenotypes and functions and elicit an HIV-specific cytotoxic T-lymphocyte response in vitro

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1327-1333 ◽  
Author(s):  
Andreas Gruber ◽  
June Kan-Mitchell ◽  
Kelli L. Kuhen ◽  
Tetsu Mukai ◽  
Flossie Wong-Staal
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Ex Vivo ◽  
T Cell Response ◽  
Adoptive T Cell Therapy ◽  
Cytotoxic T Cell ◽  
T Cell Therapy ◽  
Hiv 1

Abstract Dendritic cells (DCs) genetically modified to continually express and present antigens may be potent physiologic adjuvants for induction of prophylactic or therapeutic immunity. We have previously shown that an env and nef deleted HIV-1 vector (HIV-1ΔEN) pseudotyped with VSV-G transduced monocyte-derived macrophages as well as CD34+ precursors of DCs. Here we extended these findings with HIV-1ΔEN to highly differentiated human DCs derived in culture from circulating monocytes (DCs). In addition, a new vector derived from HIV-1ΔEN but further deleted in its remaining accessory genes vif, vpr, and vpu(HIV-1ΔEN V3) was also tested. Both vectors efficiently transduced DCs. Transduction of DCs did not significantly alter their viability or their immunophenotype when compared with untransduced DCs. Furthermore, the phagocytic potential of immature DCs, as well as their ability to differentiate into mature DCs capable of stimulating T-cell proliferation, was not affected. Finally, DCs transduced by the HIV-1ΔEN vector were able to elicit a primary antiviral cytotoxic T-cell response in autologous CD8 T cells. These results suggest that HIV-1–based vectors expressing viral antigens may be useful for in vivo active immunization as well as ex vivo priming of cytotoxic T cells for adoptive T-cell therapy.

Cross-recognition of HLA DR4 alloantigen by virus-specific CD8+ T cells: a new paradigm for self-/nonself-recognition

Blood ◽  
2009 ◽  
Vol 114 (11) ◽  
pp. 2244-2253 ◽  
Author(s):  
Michael Rist ◽  
Corey Smith ◽  
Melissa J. Bell ◽  
Scott R. Burrows ◽  
Rajiv Khanna
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cd8 T Cells ◽  
Allograft Rejection ◽  
Functional Characterization ◽  
Cell Receptor ◽  
T Cell Response ◽  
Cell Repertoire ◽  
Diverse Range

Abstract The ability of CD8+ T cells to engage a diverse range of peptide–major histocompatibility complex (MHC) complexes can also lead to cross-recognition of self and nonself peptide-MHC complexes and thus directly contribute toward allograft rejection or autoimmunity. Here we present a novel form of cross-recognition by herpes virus–specific CD8+ cytotoxic T cells that challenges the current paradigm of self/non-self recognition. Functional characterization of a human leukocyte antigen (HLA) Cw*0602-restricted cytomegalovirus-specific CD8+ T-cell response revealed an unusual dual specificity toward a pp65 epitope and the alloantigen HLA DR4. This cross-recognition of HLA DR4 alloantigen was critically dependent on the coexpression of HLA DM and was preferentially directed toward the B-cell lineage. Furthermore, allostimulation of peripheral blood lymphocytes with HLA DRB*0401-expressing cells rapidly expanded CD8+ T cells, which recognized the pp65 epitope in the context of HLA Cw*0602. T-cell repertoire analysis revealed 2 dominant populations expressing T-cell receptor beta variable (TRBV)4-3 or TRBV13, with cross-reactivity exclusively mediated by the TRBV13+ clonotypes. More importantly, cross-reactive TRBV13+ clonotypes displayed markedly lower T-cell receptor binding affinity and a distinct pattern of peptide recognition, presumably mimicking a structure presented on the HLA DR4 allotype. These results illustrate a novel mechanism whereby virus-specific CD8+ T cells can cross-recognize HLA class II molecules and may contribute toward allograft rejection and/or autoimmunity.

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