scholarly journals Stable Phenotypic Changes of the Host T Cells Are Essential to the Long-Term Stability of Latent HIV-1 Infection

2015 ◽  
Vol 89 (13) ◽  
pp. 6656-6672 ◽  
Author(s):  
Lillian Seu ◽  
Steffanie Sabbaj ◽  
Alexandra Duverger ◽  
Frederic Wagner ◽  
Joshua C. Anderson ◽  
...  

ABSTRACTThe extreme stability of the latent HIV-1 reservoir in the CD4+memory T cell population prevents viral eradication with current antiretroviral therapy. It has been demonstrated that homeostatic T cell proliferation and clonal expansion of latently infected T cells due to viral integration into specific genes contribute to this extraordinary reservoir stability. Nevertheless, given the constant exposure of the memory T cell population to specific antigen or bystander activation, this reservoir stability seems remarkable, unless it is assumed that latent HIV-1 resides exclusively in memory T cells that recognize rare antigens. Another explanation for the stability of the reservoir could be that the latent HIV-1 reservoir is associated with an unresponsive T cell phenotype. We demonstrate here that host cells of latent HIV-1 infection events were functionally altered in ways that are consistent with the idea of an anergic, unresponsive T cell phenotype. Manipulations that induced or mimicked an anergic T cell state promoted latent HIV-1 infection. Kinome analysis data reflected this altered host cell phenotype at a system-wide level and revealed how the stable kinase activity changes networked to stabilize latent HIV-1 infection. Protein-protein interaction networks generated from kinome data could further be used to guide targeted genetic or pharmacological manipulations that alter the stability of latent HIV-1 infection. In summary, our data demonstrate that stable changes to the signal transduction and transcription factor network of latently HIV-1 infected host cells are essential to the ability of HIV-1 to establish and maintain latent HIV-1 infection status.IMPORTANCEThe extreme stability of the latent HIV-1 reservoir allows the infection to persist for the lifetime of a patient, despite completely suppressive antiretroviral therapy. This extreme reservoir stability is somewhat surprising, since the latently HIV-1 infected CD4+memory T cells that form the structural basis of the viral reservoir should be exposed to cognate antigen over time. Antigen exposure would trigger a recall response and should deplete the reservoir, likely over a relatively short period. Our data demonstrate that stable and system-wide phenotypic changes to host cells are a prerequisite for the establishment and maintenance of latent HIV-1 infection events. The changes observed are consistent with an unresponsive, anergy-like T cell phenotype of latently HIV-1 infected host cells. An anergy-like, unresponsive state of the host cells of latent HIV-1 infection events would explain the stability of the HIV-1 reservoir in the face of continuous antigen exposure.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2182-2182
Author(s):  
Mohammad Hossain ◽  
Cynthia R. Giver ◽  
Ned Waller

Abstract We are investigating methods to reduce the graft-versus-host disease (GVHD) potential of donor T-cells while retaining graft-versus-leukemia (GVL) activity in allogeneic HSCT. Previous investigations by our group and others in have shown that naive CD4 T-cells induce severe acute GVHD, while memory CD4 T-cells do not induce GVHD but retain GVL activity in murine transplant models. These findings have led to studies for the development of methods to increase the number of memory T-cells available for transplant. The calcium ionophore, ionomycin, is a T-cell activating agent and mitogen. By increasing intracellular Ca2+ levels, ionomycin is induces T-cell activation through signaling mechanisms including phospholipase C activation, hydrolysis of phosphoinositides, and activation of protein kinase C. Differences in memory and naive T-cell responses to ionomycin have been attributed to resistance of memory T-cells to increases in Ca2+. Memory T-cells lack intracellular Ca2+ stores, and are also resistant to influx of Ca2+. Brief low dose ionomycin exposure (20min, 2μM) of T-cells, leading to increased density of naive T-cells, has previously been exploited as a method for separating memory and naive T-cells by Percoll gradient separation. Since ionomycin exposure induces T-cell activation through native Ca2+ dependent signaling mechanisms, we hypothesized that ionomycin-treated T-cells would shift to an activated/memory T-cell phenotype. Murine splenic T-cells were treated with 1.3μM ionomycin for 4hr. Memory and naive T-cell subsets and activation markers were analyzed by flow cytometry. 75% and 85% of untreated CD4 and CD8 T-cells, respectively, had the CD62L+ naive phenotype. These numbers were dramatically reduced to 7% and 17% after ionomycin exposure, representing a shift to the memory T-cell phenotype. Viability of T-cells was not significantly affected. The majority of remaining CD62L+ naive T-cells expressed activation markers CD25 and CD69. The fraction of CD4+CD25+Foxp3+ regulatory T-cells was also determined by intracellular staining of the transcription factor and co-expression of surface markers. CD4+CD25+Foxp3+ regulatory T-cells represented 4% of untreated CD4 T-cells and 3% of ionomycin-treated CD4 T-cells. While ionomycin has been used for many years in studies of T-cell activation, to our knowledge this is the first demonstration of a rapidly-induced shift of naive T-cells to a memory phenotype. A pilot experiment was conducted testing the GVHD activity of ionomycin-treated splenocytes (SP) in B6→ (B6 × Balb/C)CB6F1 recipients. 5 × 106 T-cell depleted bone marrow cells (TCD-BM) were transplanted along with 10 × 106 treated or untreated SP. Mice that received untreated SP all died from acute GvHD by 34 days after transplant, while all recipients of ionomycin-treated SP survived until the experiement was terminated at day 49 (average weight loss was 25%, data not shown). Continuing experients will refine the dose to further reduce GVHD symptoms and also test GVL activity of the treated cells. Treatment of donor T-cells with ionomycin may represent a clinically applicaple method to engineer donor lymphocyte infusions that are safer for HSCT patients. Figure 1. Survival of CB6F1 recipients after transplant with 5 million B6 TCD-BM and 10 million B6 splenocytes that were either untreated or stimulated ex-vivo with a combination of PMA, ionomycin and brefeldin-A for 4 hours. 5 recipient animals per group. The experiment was terminated at day 49. Figure 1. Survival of CB6F1 recipients after transplant with 5 million B6 TCD-BM and 10 million B6 splenocytes that were either untreated or stimulated ex-vivo with a combination of PMA, ionomycin and brefeldin-A for 4 hours. 5 recipient animals per group. The experiment was terminated at day 49.


2007 ◽  
Vol 76 (3) ◽  
pp. 1214-1222 ◽  
Author(s):  
Christine A. Shaw ◽  
Michael N. Starnbach

ABSTRACT Memory CD8+ T cells are essential for protective immunity against many intracellular pathogens; therefore, stimulation of this population of cells is an important goal of vaccination. We have previously shown that a detoxified derivative of Bacillus anthracis anthrax lethal toxin (LT) can deliver heterologous CD8+ T-cell epitopes to the major histocompatibility complex class I processing and presentation pathway of murine host cells and that immunization of mice with these LT-antigen fusion proteins leads to the induction of antigen-specific CD8+ T cells. In this report we extend these findings to include a detailed characterization of the phenotypic and functional properties of the T cells stimulated by the LT-based system. We found that after an initial period of expansion and contraction, antigen-specific CD8+ T cells differentiated into a pool of memory cells that produced gamma interferon and displayed in vivo cytotoxic activity. The transition to memory cells appeared to be quite rapid based on an analysis of the phenotypic marker CD127 and the effectiveness of a booster immunization administered early after the initial immunization. We also investigated the composition of the memory T-cell pool induced by this system and found that while one immunization induced a mixture of effector memory T cells (CD62Llow) and central memory T cells (CD62Lhigh), a second immunization preferentially elevated the effector memory T-cell frequency. Finally, we demonstrated that mice that received prime-boost immunizations of LT-antigen proteins were more protected in a Listeria monocytogenes challenge model than mice that received only one immunization.


Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1490
Author(s):  
Victoria Matyushenko ◽  
Irina Isakova-Sivak ◽  
Igor Kudryavtsev ◽  
Arina Goshina ◽  
Anna Chistyakova ◽  
...  

Background: New coronavirus SARS-CoV-2, a causative agent of the COVID-19 pandemic, has been circulating among humans since November 2019. Multiple studies have assessed the qualitative and quantitative characteristics of virus-specific immunity in COVID-19 convalescents, however, some aspects of the development of memory T-cell responses after natural SARS-CoV-2 infection remain uncovered. Methods: In most of published studies T-cell immunity to the new coronavirus is assessed using peptides corresponding to SARS-CoV-1 or SARS-CoV-2 T-cell epitopes, or with peptide pools covering various parts of the viral proteins. Here, we determined the level of CD4+ and CD8+ memory T-cell responses in COVID-19 convalescents by stimulating PBMCs collected 1 to 6 months after recovery with sucrose gradient-purified live SARS-CoV-2. IFNγ production by the central and effector memory helper and cytotoxic T cells was assessed by intracellular cytokine staining assay and flow cytometry. Results: Stimulation of PBMCs with live SARS-CoV-2 revealed IFNγ-producing T-helper effector memory cells with CD4+CD45RA−CCR7− phenotype, which persisted in circulation for up to 6 month after COVID-19. In contrast, SARS-CoV-2-specific IFNγ-secreting cytotoxic effector memory T cells were found at significant levels only shortly after the disease, but rapidly decreased over time. Conclusion: The stimulation of immune cells with live SARS-CoV-2 revealed a rapid decline in the pool of effector memory CD8+, but not CD4+, T cells after recovery from COVID-19. These data provide additional information on the development and persistence of cellular immune responses after natural infection, and can inform further development of T cell-based SARS-CoV-2 vaccines.


2020 ◽  
Author(s):  
Benjamin G. Wiggins ◽  
Laura J. Pallett ◽  
Xiaoyan Li ◽  
Scott P. Davies ◽  
Oliver E. Amin ◽  
...  

ABSTRACTBackground & AimsTissue-resident memory T cells (TRM) are important immune sentinels that provide efficient in situ immunity. Liver-resident CD8+ TRM have been previously described, and contribute to viral control in persistent hepatotropic infections. However, little is known regarding liver CD4+ TRM cells. Here we profiled resident and non-resident intrahepatic CD4+ T cell subsets, assessing their phenotype, function, differential generation requirements and roles in hepatotropic infection.MethodsLiver tissue was obtained from 173 subjects with (n=109) or without (n=64) hepatic pathology. Multiparametric flow cytometry and immunofluorescence imaging examined T cell phenotype, functionality and location. Liver T cell function was determined after stimulation with anti-CD3/CD28 and PMA/Ionomycin. Co-cultures of blood-derived lymphocytes with hepatocyte cell lines, primary biliary epithelial cells, and precision-cut autologous liver slices were used to investigate the acquisition of liver-resident phenotypes.ResultsCD69 expression delineated two distinct subsets in the human liver. CD69HI cells were identified as CD4+ TRM due to exclusion from the circulation, a residency-associated phenotype (CXCR6+CD49a+S1PR1-PD-1+), restriction to specific liver niches, and ability to produce robust type-1 multifunctional cytokine responses. Conversely, CD69INT were an activated T cell population also found in the peripheral circulation, with a distinct homing profile (CX3CR1+CXCR3+CXCR1+), and a bias towards IL-4 production. Frequencies of CD69INT cells correlated with the degree of fibrosis in chronic hepatitis B virus infection. Interaction with hepatic epithelia was sufficient to generate CD69INT cells, while additional signals from the liver microenvironment were required to generate liver-resident CD69HI cells.ConclusionsIntermediate and high CD69 expression demarcates two discrete intrahepatic CD4+ T cell subsets with distinct developmental and functional profiles.Graphical AbstractHighlightsCD69HI (CXCR6+CD49a+S1PR1-PD-1+) are the CD4+ TRM of the human liverHepatic CD69INTCD4+ T-cells are distinct, activated, and recirculation-competentStimulation evokes respective IFN-γ and IL-4 responses in CD69HI and CD69INT cellsCD69INT cell frequencies correlate with worsening fibrosis in chronic HBV patientsLiver slice cultures allow differentiation of CD69INT and CD69HI cells from bloodLay summaryTissue-resident memory T cells (TRM) orchestrate regional immune responses, but much of the biology of liver-resident CD4+ TRM remains unknown. We found high expression of cell-surface protein CD69 defined hepatic CD4+ TRM, while simultaneously uncovering a distinct novel recirculatory CD69INT CD4+ T cell subset. Both subsets displayed unique immune receptor profiles, were functionally skewed towards type-1 and type-2 responses respectively, and had distinct generation requirements, highlighting the potential for differential roles in the immunopathology of chronic liver diseases.


2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Wen Peng ◽  
Zhongsi Hong ◽  
Xi Chen ◽  
Hongbo Gao ◽  
Zhuanglin Dai ◽  
...  

ABSTRACT Antiretroviral therapy (ART) suppresses HIV-1 replication but fails to cure the infection. The presence of an extremely stable viral latent reservoir, primarily in resting memory CD4+ T cells, remains a major obstacle to viral eradication. The “shock and kill” strategy targets these latently infected cells and boosts immune recognition and clearance, and thus, it is a promising approach for an HIV-1 functional cure. Although some latency-reversing agents (LRAs) have been reported, no apparent clinical progress has been made, so it is still vital to seek novel and effective LRAs. Here, we report that thiostrepton (TSR), a proteasome inhibitor, reactivates latent HIV-1 effectively in cellular models and in primary CD4+ T cells from ART-suppressed individuals ex vivo. TSR does not induce global T cell activation, severe cytotoxicity, or CD8+ T cell dysfunction, making it a prospective LRA candidate. We also observed a significant synergistic effect of reactivation when TSR was combined with JQ1, prostratin, or bryostatin-1. Interestingly, six TSR analogues also show reactivation abilities that are similar to or more effective than that of TSR. We further verified that TSR upregulated expression of heat shock proteins (HSPs) in CD4+ T cells, which subsequently activated positive transcriptional elongation factor b (p-TEFb) and NF-κB signals, leading to viral reactivation. In summary, we identify TSR as a novel LRA which could have important significance for applications to an HIV-1 functional cure in the future.


Blood ◽  
2000 ◽  
Vol 95 (4) ◽  
pp. 1167-1174 ◽  
Author(s):  
Francesco Annunziato ◽  
Grazia Galli ◽  
Filomena Nappi ◽  
Lorenzo Cosmi ◽  
Roberto Manetti ◽  
...  

Human T helper (Th) cells (Th1- or Th2-oriented memory T cells as well as Th1- or Th2-polarized naive T cells) were infected in vitro with an R5-tropic HIV-1 strain (BaL) and assessed for their profile of cytokine production, CCR5 receptor expression, and HIV-1 p24 antigen (p24 Ag) production. Higher p24 Ag production was found in CCR5-negative Th2-like memory T cells than in CCR5-positive Th1-like memory T cells. By contrast, p24 Ag production was higher in Th1-polarized activated naive T cells in the first 4 days after infection. However, p24 Ag production in Th1-polarized T cells became comparable or even lower than the production in Th2-polarized populations later in infection or when the cells were infected with HIV-1BaL after secondary stimulation. The higher levels of p24 Ag production by Th1-polarized naive T cells soon after infection reflected a higher virus entry, as assessed by the single round infection assay using the HIV–chloramphenicol acetyl transferase (HIV-CAT) R5-tropic virus that contains the envelope protein of HIV-1 YU2 strain. The limitation of viral spread in the Th1-polarized populations, despite the initial higher level of T-cell entry of R5-tropic strains, was due to the ability of Th1 cells to produce greater amounts of β-chemokines than Th2 cells. In fact, an inverse correlation was observed between Th1-polarized naive T cells and Th1-like memory-activated T cells in regards to p24 Ag production and the release of the following CCR5-binding chemokines: regulated on activation normal T expressed and secreted (RANTES), macrophage inflammatory protein–1 (MIP-1), and MIP-1β. Moreover, infection with the HIV-1BaL strain of Th1-polarized T cells in the presence of a mixture of anti-RANTES, anti–MIP-1, and anti–MIP-1β neutralizing antibodies resulted in a significant increase of HIV-1 expression. These findings suggest that Th1-type responses may favor CD4+ T-cell infection by R5-tropic HIV-1 strains, but HIV-1 spread in Th1 cells is limited by their ability to produce CCR5-binding chemokines.


2019 ◽  
Vol 94 (2) ◽  
Author(s):  
Fei Yu ◽  
Qijuan Li ◽  
Xi Chen ◽  
Jun Liu ◽  
Linghua Li ◽  
...  

ABSTRACT Follicular helper T (TFH) cells have been shown to support productive human immunodeficiency virus type 1 (HIV-1) replication and to serve as a key component of the latent viral reservoir. However, the viral characteristics of this latent reservoir and the clinical relevance of this reservoir remain unclear. In this study, we assessed the tropic composition of latent viruses from peripheral TFH (pTFH), non-TFH memory, and naive CD4+ T cells from individuals with HIV-1 infections on suppressive combined antiretroviral therapy (cART). X4-tropic latent HIV-1 was preferentially enriched in pTFH cells compared to levels in the other two subsets. Interestingly, the ratio of X4-tropic latent HIV-1 in pTFH cells not only was robustly and inversely correlated with blood CD4+ T cell counts across patients but also was prognostic of CD4+ T cell recovery in individuals on long-term cART. Moreover, patients with higher X4-tropic latent HIV-1 ratios in pTFH cells showed greater risks of opportunistic coinfections. These findings reveal the characteristics of latent HIV-1 in TFH cells and suggest that the ratio of X4-tropic latent HIV-1 in pTFH cells is a valuable indicator for disease progression and cART efficacy. IMPORTANCE TFH cells have been shown to harbor a significant amount of latent HIV-1; however, the viral characteristics of this reservoir and its clinical relevance remain largely unknown. In this study, we demonstrate that X4-tropic latent HIV-1 is preferentially enriched in pTFH cells, which also accurately reflects the viral tropism shift. The ratio of X4-tropic proviruses in pTFH cells but not in other memory CD4+ T cell subsets is inversely and closely correlated with blood CD4+ T cell counts and CD4+ T cell recovery rates with cART. Our data suggest that the ratio of X4-tropic provirus in peripheral TFH cells can be easily measured and reflects disease progression and treatment outcomes during cART.


2020 ◽  
Vol 32 (9) ◽  
pp. 571-581 ◽  
Author(s):  
Shiki Takamura

Abstract Antigen-driven activation of CD8+ T cells results in the development of a robust anti-pathogen response and ultimately leads to the establishment of long-lived memory T cells. During the primary response, CD8+ T cells interact multiple times with cognate antigen on distinct types of antigen-presenting cells. The timing, location and context of these antigen encounters significantly impact the differentiation programs initiated in the cells. Moderate re-activation in the periphery promotes the establishment of the tissue-resident memory T cells that serve as sentinels at the portal of pathogen entry. Under some circumstances, moderate re-activation of T cells in the periphery can result in the excessive expansion and accumulation of circulatory memory T cells, a process called memory inflation. In contrast, excessive re-activation stimuli generally impede conventional T-cell differentiation programs and can result in T-cell exhaustion. However, these conditions can also elicit a small population of exhausted T cells with a memory-like signature and self-renewal capability that are capable of responding to immunotherapy, and restoration of functional activity. Although it is clear that antigen re-encounter during the primary immune response has a significant impact on memory T-cell development, we still do not understand the molecular details that drive these fate decisions. Here, we review our understanding of how antigen encounters and re-activation events impact the array of memory CD8+ T-cell subsets subsequently generated. Identification of the molecular programs that drive memory T-cell generation will advance the development of new vaccine strategies that elicit high-quality CD8+ T-cell memory.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Jean-François Daudelin ◽  
Mélissa Mathieu ◽  
Salix Boulet ◽  
Nathalie Labrecque

Following activation, naïve CD8+T cells will differentiate into effectors that differ in their ability to survive: some will persist as memory cells while the majority will die by apoptosis. Signals given by antigen-presenting cells (APCs) at the time of priming modulate this differential outcome. We have recently shown that, in opposition to dendritic cell (DC), CD40-activated B-(CD40-B) cell vaccination fails to efficiently produce CD8+memory T cells. Understanding why CD40-B-cell vaccination does not lead to the generation of functional long-lived memory cells is essential to define the signals that should be provided to naïve T cells by APCs. Here we show that CD40-B cells produce very low amount of IL-6 when compared to DCs. However, supplementation with IL-6 during CD40-B-cell vaccination did not improve memory generation. Furthermore, IL-6-deficient DCs maintained the capacity to promote the formation of functional CD8+effectors and memory cells. Our results suggest that in APC vaccination models, IL-6 provided by the APCs is dispensable for proper CD8+T-cell memory generation.


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