scholarly journals T-cell response to bacterial agents

2011 ◽  
Vol 5 (09) ◽  
pp. 640-645 ◽  
Author(s):  
Mario Milco D'Elios ◽  
Marisa Benagiano ◽  
Chiara Della Bella ◽  
Amedeo Amedei
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Response ◽  
Th2 Cells ◽  
T Helper ◽  
T Helper 1 ◽  
Cell Responses ◽  
Genetic And Environmental Factors ◽  
Bacteria And Fungi ◽  
Antigen Presenting

T-cell responses are crucial for the outcome of any infection. The type of effector T-cell reaction is determined by a complex interaction of antigen-presenting cells with naive T cells and involves genetic and environmental factors, including the type of antigen, cytokines, chemokines, co-stimulatory molecules, and signalling cascades. The decision for the immune response to go in a certain direction is based not on one signal alone, but rather on many different elements acting both synergistically and antagonistically, and through feedback loops leading to activation or inhibition of T cells. In the course of evolution different types of T cells have developed, such as T helper 1 (Th1) cells, which protect against intracellular bacteria; Th2 cells, which play a role against parasites; and Th17 cells, which face extracellular bacteria and fungi

scholarly journals Adenovirus Serotype 5 Vaccination Results in Suboptimal CD4 T Helper 1 Responses in Mice

2016 ◽  
Vol 91 (5) ◽  
Author(s):  
Junghwa Lee ◽  
Masao Hashimoto ◽  
Se Jin Im ◽  
Koichi Araki ◽  
Hyun-Tak Jin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Cd4 T Cell ◽  
T Helper ◽  
T Helper 1 ◽  
Cell Responses ◽  
Serotype 5 ◽  
Lcmv Infection

ABSTRACT Adenovirus serotype 5 (Ad5) is one of the most widely used viral vectors and is known to generate potent T cell responses. While many previous studies have characterized Ad5-induced CD8 T cell responses, there is a relative lack of detailed studies that have analyzed CD4 T cells elicited by Ad5 vaccination. Here, we immunized mice with Ad5 vectors encoding lymphocytic choriomeningitis virus (LCMV) glycoprotein (GP) and examined GP-specific CD4 T cell responses elicited by Ad5 vectors and compared them to those induced by an acute LCMV infection. In contrast to LCMV infection, where balanced CD4 T helper 1 (Th1) and T follicular helper (Tfh) responses were induced, Ad5 immunization resulted in a significantly reduced frequency of Th1 cells. CD4 T cells elicited by Ad5 vectors expressed decreased levels of Th1 markers, such as Tim3, SLAM, T-bet, and Ly6C, had smaller amounts of cytotoxic molecules like granzyme B, and produced less interferon gamma than CD4 T cells induced by LCMV infection. This defective CD4 Th1 response appeared to be intrinsic for Ad5 vectors and not a reflection of comparing a nonreplicating vector to a live viral infection, since immunization with a DNA vector expressing LCMV-GP generated efficient CD4 Th1 responses. Analysis at early time points (day 3 or 4) after immunization with Ad5 vectors revealed a defect in the expression of CD25 (interleukin-2 [IL-2] receptor alpha chain) on Ad5-elicited CD4 T cells, and administration of exogenous IL-2 following Ad5 immunization partially restored CD4 Th1 responses. These results suggest that impairment of Th1 commitment after Ad5 immunization could be due to reduced IL-2-mediated signaling. IMPORTANCE During viral infection, generating balanced responses of Th1 and Tfh cells is important to induce effective cell-mediated responses and provide optimal help for antibody responses. In this study, to investigate vaccine-induced CD4 T cell responses, we characterized CD4 T cells after immunization with Ad5 vectors expressing LCMV-GP in mice. Ad5 vectors led to altered effector differentiation of LCMV GP-specific CD4 T cells compared to that during LCMV infection. CD4 T cells following Ad5 immunization exhibited impaired Th1 lineage commitment, generating significantly decreased Th1 responses than those induced by LCMV infection. Our results suggest that suboptimal IL-2 signaling possibly plays a role in reduced Th1 development following Ad5 immunization.

scholarly journals CD4+ T helper cells use CD154–CD40 interactions to counteract T reg cell–mediated suppression of CD8+ T cell responses to influenza

2013 ◽  
Vol 210 (8) ◽  
pp. 1591-1601 ◽  
Author(s):  
André Ballesteros-Tato ◽  
Beatriz León ◽  
Frances E. Lund ◽  
Troy D. Randall
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Response ◽  
T Helper Cells ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
T Helper ◽  
Cell Responses

CD4+ T cells promote CD8+ T cell priming by licensing dendritic cells (DCs) via CD40–CD154 interactions. However, the initial requirement for CD40 signaling may be replaced by the direct activation of DCs by pathogen-derived signals. Nevertheless, CD40–CD154 interactions are often required for optimal CD8+ T cell responses to pathogens for unknown reasons. Here we show that CD40 signaling is required to prevent the premature contraction of the influenza-specific CD8+ T cell response. CD40 is required on DCs but not on B cells or T cells, whereas CD154 is required on CD4+ T cells but not CD8+ T cells, NKT cells, or DCs. Paradoxically, even though CD154-expressing CD4+ T cells are required for robust CD8+ T cell responses, primary CD8+ T cell responses are apparently normal in the absence of CD4+ T cells. We resolved this paradox by showing that the interaction of CD40-bearing DCs with CD154-expressing CD4+ T cells precludes regulatory T cell (T reg cell)–mediated suppression and prevents premature contraction of the influenza-specific CD8+ T cell response. Thus, CD4+ T helper cells are not required for robust CD8+ T cell responses to influenza when T reg cells are absent.

scholarly journals Determinant in Human Immunodeficiency Virus Type 1 for Efficient Replication under Cytokine-Induced CD4+ T-Helper 1 (Th1)- and Th2-Type Conditions

1999 ◽  
Vol 73 (1) ◽  
pp. 316-324 ◽  
Author(s):  
Youichi Suzuki ◽  
Yoshio Koyanagi ◽  
Yuetsu Tanaka ◽  
Tsutomu Murakami ◽  
Naoko Misawa ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
Th2 Cells ◽  
T Helper ◽  
T Helper 1 ◽  
Culture Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Cytokines are potent stimuli for CD4+-T-cell differentiation. Among them, interleukin-12 (IL-12) and IL-4 induce naive CD4+ T cells to become T-helper 1 (Th1) or Th2 cells, respectively. In this study we found that macrophage-tropic human immunodeficiency virus type 1 (HIV-1) strains replicated more efficiently in IL-12-induced Th1-type cultures derived from normal CD4+ T cells than did T-cell-line-tropic (T-tropic) strains. In contrast, T-tropic strains preferentially infected IL-4-induced Th2-type cultures derived from the same donor CD4+ T cells. Additional studies using chimeric viruses demonstrated that the V3 region of HIV-1 gp120 was the principal determinant for efficiency of replication. Cell fusion analysis showed that cells expressing envelope protein from a T-tropic strain effectively fused with IL-4-induced Th2-type culture cells. Flow cytometric analysis showed that the level of CCR5 expression was higher on IL-12-induced Th1-type culture cells, whereas CXCR4 was highly expressed on IL-4-induced Th2-type culture cells, although a low level of CXCR4 expression was observed on IL-12-induced Th1-type culture cells. These results indicate that HIV-1 isolates exhibit differences in the ability to infect CD4+-T-cell subsets such as Th1 or Th2 cells and that this difference may partly correlate with the expression of particular chemokine receptors on these cells. The findings suggest that immunological conditions are one of the factors responsible for inducing selection of HIV-1 strains.

scholarly journals A repetitive peptide of Leishmania can activate T helper type 2 cells and enhance disease progression.

1990 ◽  
Vol 172 (5) ◽  
pp. 1359-1365 ◽  
Author(s):  
F Y Liew ◽  
S M Millott ◽  
J A Schmidt
Keyword(s):  
T Cells ◽  
T Cell ◽  
Leishmania Major ◽  
T Cell Response ◽  
Interleukin 4 ◽  
Th2 Cells ◽  
Soluble Antigen ◽  
T Helper ◽  
Major Question ◽  
Helper Type

Leishmaniasis provides a biologically relevant model to analyze the heterogeneity of CD4+ T cells and may lead to answering the major question of the mechanism for the preferential induction of T helper type 1 (Th1) and Th2 cells. Using synthetic peptides corresponding to the tandemly repeating regions of Leishmania proteins, we have identified an epitope that can preferentially induce the disease-exacerbating Th2 cells in susceptible BALB/c mice. Lymph node cells from BALB/c mice immunized subcutaneously with the octamer (p183) of the repeating 10-mer peptide EAEEAARLQA proliferated strongly against the peptide as well as the soluble antigen extract (SolAg) of Leishmania major. The proliferative T cells are CD4+, major histocompatibility complex class II restricted, and secrete interleukin 4 (IL-4) but little or no IL-2 and interferon gamma when stimulated with the peptide in vitro. T cells from BALB/c mice with progressive disease, but not from BALB/c mice cured of the infection, recognized this epitope. BALB/c mice injected subcutaneously with p183 developed significantly exacerbated disease when subsequently challenged with L. major. Furthermore, subcutaneous injection with p183 prevented the subsequent induction of resistance against L. major by intravenous immunization with soluble antigen. The T cell response to p183 is H-2d restricted. Immunization of the genetically resistant B10.D2 mice with p183 also produced strong T cell responses and exacerbated disease when challenged with L. major.

scholarly journals Rap1 Functions as a Key Regulator of T-Cell and Antigen-Presenting Cell Interactions and Modulates T-Cell Responses

2002 ◽  
Vol 22 (4) ◽  
pp. 1001-1015 ◽  
Author(s):  
Koko Katagiri ◽  
Masakazu Hattori ◽  
Nagahiro Minato ◽  
Tatsuo Kinashi
Keyword(s):  
T Cells ◽  
T Cell ◽  
Interleukin 2 ◽  
T Cell Responses ◽  
T Cell Response ◽  
Dependent Manner ◽  
Cell Responses ◽  
Adhesive Interactions ◽  
Antigen Presenting ◽  
Rap1 Activation

ABSTRACT Activation of T cells by antigen requires adhesive interactions with antigen-presenting cells (APC) in which leukocyte function-associated antigen 1 (LFA-1) and intercellular adhesion molecules (ICAMs) are important. However, it is not well understood what signaling molecules regulate this process and how the modulation of adhesive events influences T-cell activation. Here we show that Rap1 is activated in T cells in an antigen-dependent manner and accumulated at the contact site of T-cell and antigen-loaded APC. Inhibition of Rap1 activation by a dominant-negative Rap1 or SPA-1, a Rap1 GTPase-activating protein, abrogates LFA-1-ICAM-1-mediated adhesive interactions with antigen-pulsed APC and the subsequent T-cell-receptor triggering and interleukin-2 production. Conversely, augmented antigen-dependent Rap1 activation by the expression of wild-type Rap1 enhances these responses but culminates in apoptosis by Fas and FasL. Thus, Rap1 functions as a key regulator of T-cell and APC interactions and modulates T-cell responses from productive activation to activation-induced cell death by regulating the strength of adhesive interactions. Moreover, constitutive Rap1 activation rendered T cells unresponsive with accumulation of p27Kip1. Our study indicates that the activation state of Rap1 has a decisive effect on the T-cell response to antigen.

scholarly journals Interferon-producing Cells Fail to Induce Proliferation of Naive T Cells but Can Promote Expansion and T Helper 1 Differentiation of Antigen-experienced Unpolarized T Cells

2003 ◽  
Vol 197 (7) ◽  
pp. 899-906 ◽  
Author(s):  
Anne Krug ◽  
Ravi Veeraswamy ◽  
Andrew Pekosz ◽  
Osami Kanagawa ◽  
Emil R. Unanue ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Mhc Class Ii ◽  
Type I ◽  
T Helper ◽  
T Helper 1 ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Antigen Presenting

Interferon-producing cells (IPCs) secrete high levels of type I interferon in response to certain viruses. The lack of lineage markers, the expression of major histocompatibility complex (MHC) class II and the capacity to stimulate allogeneic T cells have led these cells to be classified as a subset of dendritic cells (DCs), called plasmacytoid DCs (PDCs). However, the role of IPCs/PDCs in initiating primary immune responses remains elusive. Here we examined the antigen presenting capacity of murine IPCs in antigen specific systems. While CD8α+ and CD11b+ DCs induced logarithmic expansion of naive CD4 and CD8 T cells, without conferring T helper commitment at a first encounter, primary IPCs lacked the ability to stimulate naive T cells. However, when antigen-experienced, nonpolarized T cells expanded by classical DC subsets, were restimulated by IPCs, they proliferated and produced high amounts of IFN-γ. These data indicate that IPCs can effectively stimulate preactivated or memory-type T cells and exert an immune-regulatory role. They also suggest that expansion of naive T cells and acquisition of effector function during antigen-specific T cell responses may involve different antigen-presenting cell (APC) types. Independent and coordinated control of T cell proliferation and differentiation would provide the immune system with greater flexibility in regulating immune responses.

scholarly journals OX40L–OX40 Signaling in Atopic Dermatitis

2021 ◽  
Vol 10 (12) ◽  
pp. 2578
Author(s):  
Masutaka Furue ◽  
Mihoko Furue
Keyword(s):  
T Cells ◽  
Atopic Dermatitis ◽  
Memory T Cells ◽  
Effector Memory ◽  
T Helper ◽  
T Helper 1 ◽  
Therapeutic Success ◽  
T Helper 2 ◽  
Promising Target ◽  
Antigen Presenting

OX40 is one of the co-stimulatory molecules expressed on T cells, and it is engaged by OX40L, primarily expressed on professional antigen-presenting cells such as dendritic cells. The OX40L–OX40 axis is involved in the sustained activation and expansion of effector T and effector memory T cells, but it is not active in naïve and resting memory T cells. Ligation of OX40 by OX40L accelerates both T helper 1 (Th1) and T helper 2 (Th2) effector cell differentiation. Recent therapeutic success in clinical trials highlights the importance of the OX40L–OX40 axis as a promising target for the treatment of atopic dermatitis.

scholarly journals Tbx21 and Foxp3 Are Epigenetically Stabilized in T-Bet+ Tregs That Transiently Accumulate in Influenza A Virus-Infected Lungs

2021 ◽  
Vol 22 (14) ◽  
pp. 7522
Author(s):  
Yassin Elfaki ◽  
Juhao Yang ◽  
Julia Boehme ◽  
Kristin Schultz ◽  
Dunja Bruder ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Influenza A Virus ◽  
Influenza A ◽  
T Cell Subsets ◽  
T Helper 1 ◽  
T Box ◽  
Cell Responses ◽  
Accumulation Kinetics ◽  
Kinetics Of

During influenza A virus (IAV) infections, CD4+ T cell responses within infected lungs mainly involve T helper 1 (Th1) and regulatory T cells (Tregs). Th1-mediated responses favor the co-expression of T-box transcription factor 21 (T-bet) in Foxp3+ Tregs, enabling the efficient Treg control of Th1 responses in infected tissues. So far, the exact accumulation kinetics of T cell subsets in the lungs and lung-draining lymph nodes (dLN) of IAV-infected mice is incompletely understood, and the epigenetic signature of Tregs accumulating in infected lungs has not been investigated. Here, we report that the total T cell and the two-step Treg accumulation in IAV-infected lungs is transient, whereas the change in the ratio of CD4+ to CD8+ T cells is more durable. Within lungs, the frequency of Tregs co-expressing T-bet is steadily, yet transiently, increasing with a peak at Day 7 post-infection. Interestingly, T-bet+ Tregs accumulating in IAV-infected lungs displayed a strongly demethylated Tbx21 locus, similarly as in T-bet+ conventional T cells, and a fully demethylated Treg-specific demethylated region (TSDR) within the Foxp3 locus. In summary, our data suggest that T-bet+ but not T-bet− Tregs are epigenetically stabilized during IAV-induced infection in the lung.

scholarly journals Rapid Development of Th2 Activity During T Cell Priming

2003 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Adam F. Cunningham ◽  
Kai-Michael Toellner
Keyword(s):  
T Cells ◽  
T Cell ◽  
Rapid Development ◽  
Critical Role ◽  
Cell Polarization ◽  
Th2 Cells ◽  
Th1 Cells ◽  
T Helper ◽  
Th 1 ◽  
Th1 And Th2

The paradigm of T helper-1 (Th-1) and Th-2 cells developing from non-committed naïve precursors is firmly established. Th1 cells are characterized by IFN production and, in mice, the selective switching to IgG2a. Conversely IL-4 production and selective switching to IgG1 and IgE characterize Th2 cells. Analysis of Th2 inductionin vitroindicates that this polarization develops gradually in T cells activated by anti-CD3 in the presence of IL-4; conversely anti-CD3 and IFN induce Th1 cells. In this report, we explore evidence that indicates that the T helper cell polarizationin vivocannot solely be explained by the cytokine environment. This is provided by studying the early acquisition of Th1 and Th2 activities during responses to a mixture of Th1 and Th2-inducing antigens. It is shown that these divergent forms of T cell help can rapidly develop in cells within a single lymph node. It is argued that early polarization to show Th-1 or Th-2 behavior can be induced by signals delivered during cognate interaction between virgin T cells and dendritic cells, in the absence of type 1 or type 2 cytokines. This contrasts with the critical role of the cytokines in reinforcing the Th-phenotype and selectively expanding T helper clones.

Stimulation of autologous proliferative and cytotoxic T-cell responses by “leukemic dendritic cells” derived from blast cells in acute myeloid leukemia

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2764-2771 ◽  
Author(s):  
Beth D. Harrison ◽  
Julie A. Adams ◽  
Mark Briggs ◽  
Michelle L. Brereton ◽  
John A. Liu Yin
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Dendritic Cells ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Responses ◽  
Cell Responses ◽  
Antigen Presenting ◽  
Acute Myeloid ◽  
Stimulation Of

Abstract Effective presentation of tumor antigens is fundamental to strategies aimed at enrolling the immune system in eradication of residual disease after conventional treatments. Myeloid malignancies provide a unique opportunity to derive dendritic cells (DCs), functioning antigen-presenting cells, from the malignant cells themselves. These may then co-express leukemic antigens together with appropriate secondary signals and be used to generate a specific, antileukemic immune response. In this study, blasts from 40 patients with acute myeloid leukemia (AML) were cultured with combinations of granulocyte-macrophage colony-stimulating factor, interleukin 4, and tumor necrosis factor α, and development to DCs was assessed. After culture, cells from 24 samples exhibited morphological and immunophenotypic features of DCs, including expression of major histocompatibility complex class II, CD1a, CD83, and CD86, and were potent stimulators in an allogeneic mixed lymphocyte reaction (MLR). Stimulation of autologous T-cell responses was assessed by the proliferative response of autologous T cells to the leukemic DCs and by demonstration of the induction of specific, autologous, antileukemic cytotoxicity. Of 17 samples, 11 were effective stimulators in the autologous MLR, and low, but consistent, autologous, antileukemic cytotoxicity was induced in 8 of 11 cases (mean, 27%; range, 17%-37%). This study indicates that cells with enhanced antigen-presenting ability can be generated from AML blasts, that these cells can effectively prime autologous cytotoxic T cells in vitro, and that they may be used as potential vaccines in the immunotherapy of AML.

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