scholarly journals Intestinal CD4 Depletion in HIV / SIV Infection

2019 ◽  
Vol 15 (1) ◽  
pp. 76-91
Author(s):  
Ronald S. Veazey

Among the most significant findings in the pathogenesis of HIV infection was the discovery that almost total depletion of intestinal CD4+ T cells occurs rapidly after SIV or HIV infection, regardless of the route of exposure, and long before CD4+ T cell losses occur in blood or lymph nodes. Since these seminal discoveries, we have learned much about mucosal and systemic CD4+ T cells, and found several key differences between the circulating and intestinal CD4+ T cell subsets, both in phenotype, relative proportions, and functional capabilities. Further, specific subsets of CD4+ T cells are selectively targeted and eliminated first, especially cells critically important for initiating primary immune responses, and for maintenance of mucosal integrity (Th1, Th17, and Th22 cells). This simultaneously results in loss of innate immune responses, and loss of mucosal integrity, resulting in mucosal, and systemic immune activation that drives proliferation and activation of new target cells throughout the course of infection. The propensity for the SIV/HIV to infect and efficiently replicate in specific cells also permits viral persistence, as the mucosal and systemic activation that ensues continues to damage mucosal barriers, resulting in continued influx of target cells to maintain viral replication. Finally, infection and elimination of recently activated and proliferating CD4+ T cells, and infection and dysregulation of Tfh and other key CD4+ T cell results in hyperactive, yet non-protective immune responses that support active viral replication and evolution, and thus persistence in host tissue reservoirs, all of which continue to challenge our efforts to design effective vaccine or cure strategies.

2021 ◽  
Vol 17 (4) ◽  
pp. e1009522
Author(s):  
Orion Tong ◽  
Gabriel Duette ◽  
Thomas Ray O’Neil ◽  
Caroline M. Royle ◽  
Hafsa Rana ◽  
...  

Although HIV infection inhibits interferon responses in its target cells in vitro, interferon signatures can be detected in vivo soon after sexual transmission, mainly attributed to plasmacytoid dendritic cells (pDCs). In this study, we examined the physiological contributions of pDCs to early HIV acquisition using coculture models of pDCs with myeloid DCs, macrophages and the resting central, transitional and effector memory CD4 T cell subsets. pDCs impacted infection in a cell-specific manner. In myeloid cells, HIV infection was decreased via antiviral effects, cell maturation and downregulation of CCR5 expression. In contrast, in resting memory CD4 T cells, pDCs induced a subset-specific increase in intracellular HIV p24 protein expression without any activation or increase in CCR5 expression, as measured by flow cytometry. This increase was due to reactivation rather than enhanced viral spread, as blocking HIV entry via CCR5 did not alter the increased intracellular p24 expression. Furthermore, the load and proportion of cells expressing HIV DNA were restricted in the presence of pDCs while reverse transcriptase and p24 ELISA assays showed no increase in particle associated reverse transcriptase or extracellular p24 production. In addition, PDCs also markedly induced the expression of CD69 on infected CD4 T cells and other markers of CD4 T cell tissue retention. These phenotypic changes showed marked parallels with resident memory CD4 T cells isolated from anogenital tissue using enzymatic digestion. Production of IFNα by pDCs was the main driving factor for all these results. Thus, pDCs may reduce HIV spread during initial mucosal acquisition by inhibiting replication in myeloid cells while reactivating latent virus in resting memory CD4 T cells and retaining them for immune clearance.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3106-3106
Author(s):  
Sachi Tsunemi ◽  
Tsuyoshi Iwasaki ◽  
Takehito Imado ◽  
Satoshi Higasa ◽  
Eizo Kakishita ◽  
...  

Abstract Human immunodeficiency virus (HIV) infection is characterized by marked defects in CD4+ helper T cell (Th) functions that commonly progress to a substantial decline in peripheral CD4+ T cell counts. However, the mechanisms responsible for the loss of Th functions in HIV-infected patients independent of CD4+ T cell counts remains unclear. CD4+CD25+ regulatory T cells (T Reg) are essential for down-regulation of both autoreactive and alloreactive T cells. Therefore, we decided to investigate the role of T Reg in immune status of HIV-infected patients. We examined the expression of cell surface CD25, cytoplasmic IL-4 and cytoplasmic IFN-gamma in peripheral blood CD4+ T cells from both healthy controls (n=9) and HIV-infected patients (n=43). We also compared T Reg functions between the 2 groups. CD4+CD25+ T Reg isolated from both HIV-infected patients and healthy controls strongly expressed CD45RO, HLA-DR, and FoxP3, and suppressed the proliferation of CD4+CD25− T cells, suggesting that CD4+CD25+ T cells from both healthy controls and HIV-infected patients possess phenotypic and functional characteristics of Treg. CD4+CD25high T cells are a subset of circulating CD4+CD25+ T cells in normal humans and exhibit strong in vitro regulatory functions similar to those reported for murine CD4+CD25+ T Reg. We measured the frequency of CD4+CD25high T Reg by analysis of surface CD25 on CD4+ T cells in peripheral blood samples. We also examined Th1 and Th2 frequencies by analysis of cytoplasmic IFN-gamma and IL-4 levels in CD4+ T cells. T Reg from HIV-infected patients with detectable plasma HIV-1 RNA showed a statistically significant increase in CD4+CD25high cell frequency (p<0.05) compared to healthy controls, with T Reg frequencies inversely proportional to CD4+ T cell numbers (p<0.01). However, in HIV-infected patients with undetectable plasma HIV-RNA, frequencies of CD4+CD25high T Reg were not increased and not related to CD4+ T cell numbers. In both HIV-infected patient groups, T Reg frequency was inversely related to Th1 frequency (detectable: p<0.05, undetectable: p<0.001), but positively related to Th2 frequency (detectable: p<0.01, undetectable: p<0.001). Our results indicate that increased frequencies of peripheral blood T Reg were related to disease progression as measured by detectable plasma HIV-1 RNA, decreased peripheral blood CD4+ T cell counts, and polarization toward Th2 immune responses in HIV-infected patients. HIV infection may lead to induction of T reg that inhibit antiviral immune responses, resulting in the progression of the disease. Manipulation of T Reg could help restore antiviral immune responses in HIV infection, and prevent the progression of HIV infection.


2020 ◽  
Author(s):  
Anastassia Mikhailova ◽  
José Carlos Valle-Casuso ◽  
Annie David ◽  
Valérie Monceaux ◽  
Stevenn Volant ◽  
...  

ABSTRACTHIV-1 successfully establishes long-term infection in its target cells despite viral cytotoxic effects. We have recently shown that cell metabolism is an important factor driving CD4+ T-cell susceptibility to HIV-1 and the survival of infected cells. We show here that expression of anti-apoptotic clone 11 (AAC-11), an anti-apoptotic factor upregulated in many cancers, increased with progressive CD4+ T cell memory differentiation in association with the expression of cell cycle, activation and metabolism genes and correlated with susceptibility to HIV-1 infection. Synthetic peptides based on the LZ domain sequence of AAC-11, responsible for its interaction with molecular partners, were previously shown to be cytotoxic to cancer cells. Here we observed that these peptides also blocked HIV-1 infection by inducing cell death of HIV-1 susceptible primary CD4+ T-cells across all T-cell subsets. The peptides targeted metabolically active cells and had the greatest effect on effector and transitional CD4+ T cell memory subsets. Our results suggest that AAC-11 survival pathway is potentially involved in the survival of HIV-1 infectable cells and provide a proof of principle that some cellular characteristics can be targeted to eliminate the cells offering the best conditions to sustain HIV-1 replication.IMPORTANCEAlthough antiretroviral treatment efficiently blocks HIV multiplication, it cannot eliminate the cells already carrying integrated proviruses. In the search for a HIV cure the identification of new potential targets to selectively eliminate infected cells is of the outmost importance. We show here that peptides derived from the anti-apoptotic clone 11 (AAC-11), which expression levels correlated with susceptibility to HIV-1 infection of CD4+ T-cells, induced cytotoxicity in CD4+ T-cells showing the highest levels of activation and metabolic activity, conditions known to favor HIV-1 infection. Accordingly, CD4+ T-cells that survived the cytotoxic action of the AAC-11 peptides were resistant to HIV-1 replication. Our results identify a new potential molecular pathway to target HIV-1 infection.


2018 ◽  
Vol 92 (23) ◽  
Author(s):  
Franco Pissani ◽  
Bianca Schulte ◽  
Michael A. Eller ◽  
Bruce T. Schultz ◽  
Silvia Ratto-Kim ◽  
...  

ABSTRACT To date, six vaccine strategies have been evaluated in clinical trials for their efficacy at inducing protective immune responses against HIV infection. However, only the ALVAC-HIV/AIDSVAX B/E vaccine (RV144 trial) has demonstrated protection, albeit modestly (31%; P = 0.03). One potential correlate of protection was a low-frequency HIV-specific CD4 T cell population with diverse functionality. Although CD4 T cells, particularly T follicular helper (Tfh) cells, are critical for effective antibody responses, most studies involving HIV vaccines have focused on humoral immunity or CD8 T cell effector responses, and little is known about the functionality and frequency of vaccine-induced CD4 T cells. We therefore assessed responses from several phase I/II clinical trials and compared them to responses to natural HIV-1 infection. We found that all vaccines induced a lower magnitude of HIV-specific CD4 T cell responses than that observed for chronic infection. Responses differed in functionality, with a CD40 ligand (CD40L)-dominated response and more Tfh cells after vaccination, whereas chronic HIV infection provoked tumor necrosis factor alpha (TNF-α)-dominated responses. The vaccine delivery route further impacted CD4 T cells, showing a stronger Th1 polarization after dendritic cell delivery than after intramuscular vaccination. In prime/boost regimens, the choice of prime and boost influenced the functional profile of CD4 T cells to induce more or less polyfunctionality. In summary, vaccine-induced CD4 T cell responses differ remarkably between vaccination strategies, modes of delivery, and boosts and do not resemble those induced by chronic HIV infection. Understanding the functional profiles of CD4 T cells that best facilitate protective antibody responses will be critical if CD4 T cell responses are to be considered a clinical trial go/no-go criterion. IMPORTANCE Only one HIV-1 candidate vaccine strategy has shown protection, albeit marginally (31%), against HIV-1 acquisition, and correlates of protection suggested that a multifunctional CD4 T cell immune response may be important for this protective effect. Therefore, the functional phenotypes of HIV-specific CD4 T cell responses induced by different phase I and phase II clinical trials were assessed to better show how different vaccine strategies influence the phenotype and function of HIV-specific CD4 T cell immune responses. The significance of this research lies in our comprehensive comparison of the compositions of the T cell immune responses to different HIV vaccine modalities. Specifically, our work allows for the evaluation of vaccination strategies in terms of their success at inducing Tfh cell populations.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A770-A770
Author(s):  
Michael Brown ◽  
Zachary McKay ◽  
Yuanfan Yang ◽  
Darell Bigner ◽  
Smita Nair ◽  
...  

BackgroundPVSRIPO, a recombinant poliovirus derived from the live-attenuated Sabin oral polio vaccine strain, is being tested in multi-institutional phase II clinical trials for recurrent glioblastoma (NCT04479241) and unresectable, PD-1 refractory melanoma (NCT04577807) in combination with PD1 blockade. PVSRIPO capsid is identical to the Sabin vaccine strain and >99% identical to the inactivated Polio vaccine (IPOL, Salk), against which public health mandated childhood vaccination is near universal. In non-vaccinated mice, PVSRIPO mediates antitumor efficacy in a replication-dependent manner via engaging innate inflammation and antitumor T cells. Accordingly, it is anticipated that pre-existing immunity to PVSRIPO impedes antitumor therapy. However, recent evidence indicates that immunological 'recall', or reactivation of memory T cells, may mediate anti-tumor effects.MethodsThe impact of prior polio vs control (KLH) vaccination on intratumor viral replication, tumor inflammation, and overall tumor growth after intratumor PVSRIPO therapy was assessed in murine tumor models. The role of polio capsid and tetanus recall antigens in mediating intratumor inflammation and antitumor efficacy was similarly studied in mice non-permissive to PVSRIPO infection. To mechanistically define antitumor effects of polio recall, B cell and CD8 T cell knockout mice were used, in addition to adoptive transfer of CD4+ T cells from vaccinated mice. Intratumor polio or tetanus recall antigen therapy was performed after OT-I transfer (OVA-specific T cells) in the B16-OVA melanoma model to gauge antitumor T cell activity. Lastly, the inflammatory effects of polio and tetanus antigens was tested in human peripheral blood mononuclear cells (PBMCs).ResultsDespite curtailing intratumor viral replication, prior polio vaccination in mice potentiated subsequent antitumor efficacy of PVSRIPO. Intratumor recall responses induced by polio and tetanus antigens also delayed tumor growth. Recall antigen therapy was associated with marked intratumor influx of eosinophils, conventional CD4+ T cells, and increased expression of IFN-g, TNF, and Granzyme B in tumor infiltrating T cells. The antitumor efficacy of polio recall antigen was mediated by CD4+ T cells, partially depended upon CD8+ T cells, and was impaired by B cells. Both polio and tetanus recall antigen therapy bolstered the antitumor function of tumor-specific OT-I CD8+ T cells. Polio and tetanus antigens induced CXCL10 and type I/II/III IFNs in PBMCs in vitro.ConclusionsChildhood vaccine-specific CD4+ T cells hold cancer immunotherapy potential. In the context of PVSRIPO therapy, antitumor and inflammatory effects of polio vaccine-specific CD4+ T cell recall supersedes inhibitory effects of attenuated intratumor viral replication, and represents a novel mechanism of action.Ethics ApprovalThe animal work described in this study was approved by the Duke University IACUC.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3684-3684
Author(s):  
Matthew J Ahearne ◽  
Kaljit S Bhuller ◽  
Roger Hew ◽  
Giovanna Roncador ◽  
Martin J.S. Dyer ◽  
...  

Abstract Abstract 3684 CD4+ T-cells can be distinguished into subsets on the basis of surface marker expression and growth factor production. Follicular helper T-cells (Tfh cells) are characterized by the co-expression of surface markers (CD4, ICOS, PD1 and CXCR5) and nuclear BCL6. Normal germinal centre formation requires Tfh cells but is repressed by another CD4+ T-cell subset, Tregs, (demonstrating CD4 and CD25 expression with nuclear FoxP3). The numbers and architecture of infiltrating T-cells predict clinical outcome in follicular lymphoma but although T-cells are a component of diffuse large B cell lymphoma (DLBCL), the relative numbers of CD4+ T-cells and their Tfh and Treg subsets or their association with clinical outcome is not known. We used immunohistochemistry to investigate infiltration by total CD4+, Treg and Tfh cells in cases (n=23) from one centre. The male:female was 1.3:1.0, the age range was 30 to 78 years (median 65 years) and the anticipated association between overall survival and LDH (logrank test, P=0.02) was observed. Patients were treated with R-CHOP with a 21-day cycle. Histological sections were stained with anti-CD4, anti-PD1 and anti-FoxP3 antibodies. For each antibody the area of staining was measured using ImageJ software from 10 high power fields from the same area of each histological section. Tfh cells were identified by strong surface expression of PD1 and Tregs by nuclear expression of FoxP3. CD4+ T-cell infiltration varied by ∼50-fold, and could be diffuse or focal. In 13 cases (57%) the majority of CD4+ T-cells were neither FoxP3+ nor PD1+. Total CD4+ T-cell numbers were positively correlated with FoxP3 (P=0.04) (Figure 1) and with PD1 (P=0.009) (Figure 2) expressing cells suggesting that these subsets were expanded as part of a reaction to the lymphoma capable of stimulating several CD4+ T-cell subsets. High CD4+ (Figure 3) and PD1+ staining predicted good clinical outcome (logrank test, P=0.08) with median survival not being reached at 5 years, but the amount of FoxP3+ staining appeared to be a superior prognostic marker (logrank test, P=0.0069) (Figure 4). There was no association between the cell of origin classification of DLBCL (GCB or ABC) as defined immunohistochemically, and CD4, FoxP3 or PD1 expression. In summary, we have shown that numbers of infiltrating CD4+ T-cells vary between cases of DLBCL and comprises several T-cell subsets including Treg and Tfh cells. No consensus has been reached on the clinical significance of FoxP3+ cell infiltration in DLBCL. Whilst some workers have shown FoxP3 to be associated with a good clinical outcome (Tzankov A., et al. 2008; Lee N., et al. 2008), others have not found a relationship to prognosis (Hasselblom S. et al., 2007). Our data shows that the FoxP3+ Treg cell subset is associated with good clinical outcome but surprisingly we found that both increased total CD4+ T-cells and PD1+ Tfh cells also carry a good prognosis. Disclosures: Wagner: Roche: Honoraria.


2000 ◽  
Vol 191 (12) ◽  
pp. 2159-2170 ◽  
Author(s):  
Kevin J. Maloy ◽  
Christoph Burkhart ◽  
Tobias M. Junt ◽  
Bernhard Odermatt ◽  
Annette Oxenius ◽  
...  

To analyze the antiviral protective capacities of CD4+ T helper (Th) cell subsets, we used transgenic T cells expressing an I-Ab–restricted T cell receptor specific for an epitope of vesicular stomatitis virus glycoprotein (VSV-G). After polarization into Th1 or Th2 effectors and adoptive transfer into T cell–deficient recipients, protective capacities were assessed after infection with different types of viruses expressing the VSV-G. Both Th1 and Th2 CD4+ T cells could transfer protection against systemic VSV infection, by stimulating the production of neutralizing immunoglobulin G antibodies. However, only Th1 CD4+ T cells were able to mediate protection against infection with recombinant vaccinia virus expressing the VSV-G (Vacc-IND-G). Similarly, only Th1 CD4+ T cells were able to rapidly eradicate Vacc-IND-G from peripheral organs, to mediate delayed-type hypersensitivity responses against VSV-G and to protect against lethal intranasal infection with VSV. Protective capacity correlated with the ability of Th1 CD4+ T cells to rapidly migrate to peripheral inflammatory sites in vivo and to respond to inflammatory chemokines that were induced after virus infection of peripheral tissues. Therefore, the antiviral protective capacity of a given CD4+ T cell is governed by the effector cytokines it produces and by its migratory capability.


2021 ◽  
Vol Volume 14 ◽  
pp. 5149-5163
Author(s):  
Di Wang ◽  
Yu Jiang ◽  
Yangzi Song ◽  
Yongqin Zeng ◽  
Cuilin Li ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Quentin Le Hingrat ◽  
Irini Sereti ◽  
Alan L. Landay ◽  
Ivona Pandrea ◽  
Cristian Apetrei

CD4+ T-cell depletion is pathognomonic for AIDS in both HIV and simian immunodeficiency virus (SIV) infections. It occurs early, is massive at mucosal sites, and is not entirely reverted by antiretroviral therapy (ART), particularly if initiated when T-cell functions are compromised. HIV/SIV infect and kill activated CCR5-expressing memory and effector CD4+ T-cells from the intestinal lamina propria. Acute CD4+ T-cell depletion is substantial in progressive, nonprogressive and controlled infections. Clinical outcome is predicted by the mucosal CD4+ T-cell recovery during chronic infection, with no recovery occurring in rapid progressors, and partial, transient recovery, the degree of which depends on the virus control, in normal and long-term progressors. The nonprogressive infection of African nonhuman primate SIV hosts is characterized by partial mucosal CD4+ T-cell restoration, despite high viral replication. Complete, albeit very slow, recovery of mucosal CD4+ T-cells occurs in controllers. Early ART does not prevent acute mucosal CD4+ T-cell depletion, yet it greatly improves their restoration, sometimes to preinfection levels. Comparative studies of the different models of SIV infection support a critical role of immune activation/inflammation (IA/INFL), in addition to viral replication, in CD4+ T-cell depletion, with immune restoration occurring only when these parameters are kept at bay. CD4+ T-cell depletion is persistent, and the recovery is very slow, even when both the virus and IA/INFL are completely controlled. Nevertheless, partial mucosal CD4+ T-cell recovery is sufficient for a healthy life in natural hosts. Cell death and loss of CD4+ T-cell subsets critical for gut health contribute to mucosal inflammation and enteropathy, which weaken the mucosal barrier, leading to microbial translocation, a major driver of IA/INFL. In turn, IA/INFL trigger CD4+ T-cells to become either viral targets or apoptotic, fueling their loss. CD4+ T-cell depletion also drives opportunistic infections, cancers, and comorbidities. It is thus critical to preserve CD4+ T cells (through early ART) during HIV/SIV infection. Even in early-treated subjects, residual IA/INFL can persist, preventing/delaying CD4+ T-cell restoration. New therapeutic strategies limiting mucosal pathology, microbial translocation and IA/INFL, to improve CD4+ T-cell recovery and the overall HIV prognosis are needed, and SIV models are extensively used to this goal.


2020 ◽  
Author(s):  
Shiyu Wang ◽  
Longlong Wang ◽  
Ya Liu

AbstractCD4+ T cells are key components of adaptive immunity. The cell differentiation equips CD4+ T cells with new functions. However, the effect of cell differentiation on T cell receptor (TCR) repertoire is not investigated. Here, we examined the features of TCR beta (TCRB) repertoire of the top clones within naïve, memory and regular T cell (Treg) subsets: repertoire structure, gene usage, length distribution and sequence composition. First, we found that memory subsets and Treg would be discriminated from naïve by the features of TCRB repertoire. Second, we found that the correlations between the features of memory subsets and naïve were positively related to differentiation levels of memory subsets. Third, we found that public clones presented a reduced proportion and a skewed sequence composition in differentiated subsets. Furthermore, we found that public clones led naïve to recognize a broader spectrum of antigens than other subsets. Our findings suggest that TCRB repertoire of CD4+ T cell subsets is skewed in a differentiation-depended manner. Our findings show that the variations of public clones contribute to these changes. Our findings indicate that the reduce of public clones in differentiation trim the antigen specificity of CD4+ T cells. The study unveils the physiological effect of memory formation and facilitates the selection of proper CD4+ subset for cellular therapy.


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