scholarly journals Simian Immunodeficiency Virus SIVagm Efficiently Utilizes Non-CCR5 Entry Pathways in African Green Monkey Lymphocytes: Potential Role for GPR15 and CXCR6 as Viral Coreceptors

2015 ◽  
Vol 90 (5) ◽  
pp. 2316-2331 ◽  
Author(s):  
Nadeene E. Riddick ◽  
Fan Wu ◽  
Kenta Matsuda ◽  
Sonya Whitted ◽  
Ilnour Ourmanov ◽  
...  
Keyword(s):  
T Cells ◽  
Mononuclear Cells ◽  
Rhesus Macaques ◽  
Target Cells ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Sooty Mangabeys ◽  
Natural Hosts

ABSTRACTAfrican green monkeys (AGM) are natural hosts of simian immunodeficiency virus (SIV), and infection in these animals is generally nonpathogenic, whereas infection of nonnatural hosts, such as rhesus macaques (RM), is commonly pathogenic. CCR5 has been described as the primary entry coreceptor for SIVin vivo, while human-derived CXCR6 and GPR15 also appear to be usedin vitro. However, sooty mangabeys that are genetically deficient in CCR5 due to an out-of-frame deletion are infectible with SIVsmm, indicating that SIVsmm can use alternative coreceptorsin vivo. In this study, we examined the CCR5 dependence of SIV strains derived from vervet AGM (SIVagmVer) and the ability of AGM-derived GPR15 and CXCR6 to serve as potential entry coreceptors. We found that SIVagmVer replicated efficiently in AGM and RM peripheral blood mononuclear cells (PBMC) in the presence of the CCR5 antagonist maraviroc, despite the fact that maraviroc was capable of blocking the CCR5-tropic strains SIVmac239, SIVsmE543-3, and simian-human immunodeficiency virus SHIV-AD8 in RM PBMC. We also found that AGM CXCR6 and AGM GPR15, to a lesser extent, supported entry of pseudotype viruses bearing SIVagm envelopes, including SIVagm transmitted/founder envelopes. Lastly, we found that CCR5, GPR15, and CXCR6 mRNAs were detected in AGM and RM memory CD4+T cells. These results suggest that GPR15 and CXCR6 are expressed on AGM CD4+T cells and are potential alternative coreceptors for SIVagm usein vivo. These data suggest that the use of non-CCR5 entry pathways may be a common feature of SIV replication in natural host species, with the potential to contribute to nonpathogenicity in these animals.IMPORTANCEAfrican green monkeys (AGM) are natural hosts of SIV, and infection in these animals generally does not cause AIDS, whereas SIV-infected rhesus macaques (RM) typically develop AIDS. Although it has been reported that SIV generally uses CD4 and CCR5 to enter target cellsin vivo, other molecules, such as GPR15 and CXCR6, also function as SIV coreceptorsin vitro. In this study, we investigated whether SIV from vervet AGM can use non-CCR5 entry pathways, as has been observed in sooty mangabeys. We found that SIVagmVer efficiently replicated in AGM and RM peripheral blood mononuclear cells in the presence of the CCR5 antagonist maraviroc, suggesting that non-CCR5 entry pathways can support SIVagm entry. We found that AGM-derived GPR15 and CXCR6 support SIVagmVer entryin vitroand may serve as entry coreceptors for SIVagmin vivo, since their mRNAs were detected in AGM memory CD4+T cells, the preferred target cells of SIV.

scholarly journals In Vivo Attenuation of Simian Immunodeficiency Virus by Disruption of a Tyrosine-Dependent Sorting Signal in the Envelope Glycoprotein Cytoplasmic Tail

2001 ◽  
Vol 75 (1) ◽  
pp. 278-291 ◽  
Author(s):  
Patricia N. Fultz ◽  
Patricia J. Vance ◽  
Michael J. Endres ◽  
Binli Tao ◽  
Jeffrey D. Dvorin ◽  
...  
Keyword(s):  
Envelope Glycoprotein ◽  
Mononuclear Cells ◽  
Stop Codon ◽  
Rhesus Macaques ◽  
Cytoplasmic Tail ◽  
Peripheral Blood Mononuclear ◽  
Sorting Signal ◽  
Immunodeficiency Virus

ABSTRACT Attenuated simian immunodeficiency viruses (SIVs) have been described that produce low levels of plasma virion RNA and exhibit a reduced capacity to cause disease. These viruses are particularly useful in identifying viral determinants of pathogenesis. In the present study, we show that mutation of a highly conserved tyrosine (Tyr)-containing motif (Yxxφ) in the envelope glycoprotein (Env) cytoplasmic tail (amino acids YRPV at positions 721 to 724) can profoundly reduce the in vivo pathogenicity of SIVmac239. This domain constitutes both a potent endocytosis signal that reduces Env expression on infected cells and a sorting signal that directs Env expression to the basolateral surface of polarized cells. Rhesus macaques were inoculated with SIVmac239 control or SIVmac239 containing either a Tyr-721-to-Ile mutation (SIVmac239Y/I) or a deletion of Tyr-721 and the preceding glycine (ΔGY). To assess the in vivo replication competence, all viruses contained a stop codon innef that has been shown to revert during in vivo but not in vitro replication. All three control animals developed high viral loads and disease. One of two animals that received SIVmac239Y/I and two of three animals that received SIVmac239ΔGY remained healthy for up to 140 weeks with low to undetectable plasma viral RNA levels and normal CD4+ T-cell percentages. These animals exhibited ongoing viral replication as determined by detection of viral sequences and culturing of mutant viruses from peripheral blood mononuclear cells and persistent anti-SIV antibody titers. In one animal that received SIVmac239Y/I, the Ile reverted to a Tyr and was associated with a high plasma RNA level and disease, while one animal that received SIVmac239ΔGY also developed a high viral load that was associated with novel and possibly compensatory mutations in the TM cytoplasmic domain. In all control and experimental animals, the nefstop codon reverted to an open reading frame within the first 2 months of inoculation, indicating that the mutant viruses had replicated well enough to repair this mutation. These findings indicate that the Yxxφ signal plays an important role in SIV pathogenesis. Moreover, because mutations in this motif may attenuate SIV through mechanisms that are distinct from those caused by mutations in nef, this Tyr-based sorting signal represents a novel target for future models of SIV and human immunodeficiency virus attenuation that could be useful in new vaccine strategies.

scholarly journals A Theileria parva Isolate of Low Virulence Infects a Subpopulation of Lymphocytes

2011 ◽  
Vol 80 (3) ◽  
pp. 1267-1273 ◽  
Author(s):  
Heshborne S. Tindih ◽  
Dirk Geysen ◽  
Bruno M. Goddeeris ◽  
Elias Awino ◽  
Dirk A. E. Dobbelaere ◽  
...  
Keyword(s):  
T Cells ◽  
Mononuclear Cells ◽  
Γδ T Cells ◽  
Target Cells ◽  
Theileria Parva ◽  
Logarithmic Growth Phase ◽  
Peripheral Blood Mononuclear ◽  
Content Type

Theileria parvais a tick-transmitted protozoan parasite that infects and transforms bovine lymphocytes. We have previously shown thatTheileria parvaChitongo is an isolate with a lower virulence than that ofT. parvaMuguga. Lower virulence appeared to be correlated with a delayed onset of the logarithmic growth phase ofT. parvaChitongo-transformed peripheral blood mononuclear cells afterin vitroinfection. In the current study, infection experiments with WC1+γδ T cells revealed that onlyT. parvaMuguga could infect these cells and that no transformed cells could be obtained withT. parvaChitongo sporozoites. Subsequent analysis of the susceptibility of different cell lines and purified populations of lymphocytes to infection and transformation by both isolates showed thatT. parvaMuguga sporozoites could attach to and infect CD4+, CD8+, and WC1+T lymphocytes, butT. parvaChitongo sporozoites were observed to bind only to the CD8+T cell population. Flow cytometry analysis of established, transformed clones confirmed this bias in target cells.T. parvaMuguga-transformed clones consisted of different cell surface phenotypes, suggesting that they were derived from either host CD4+, CD8+, or WC1+T cells. In contrast, allin vitroandin vivoT. parvaChitongo-transformed clones expressed CD8 but not CD4 or WC1, suggesting that theT. parvaChitongo-transformed target cells were exclusively infected CD8+lymphocytes. Thus, a role of cell tropism in virulence is likely. Since the adhesion molecule p67 is 100% identical between the two strains, a second, high-affinity adhesin that determines target cell specificity appears to exist.

scholarly journals Precision engineering of an anti-HLA-A2 chimeric antigen receptor in regulatory T cells for transplant immune tolerance

2021 ◽  
Author(s):  
Yannick D. Muller ◽  
Leonardo M.R. Ferreira ◽  
Emilie Ronin ◽  
Patrick Ho ◽  
Vinh Nguyen ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Chimeric Antigen Receptor ◽  
Mononuclear Cells ◽  
Antigen Receptor ◽  
Single Chain ◽  
Transplant Tolerance ◽  
Peripheral Blood Mononuclear

Infusion of regulatory T cells (Tregs) engineered with a chimeric antigen receptor (CAR) targeting donor-derived human leukocyte antigen (HLA) is a promising strategy to promote transplant tolerance. Here, we describe an anti-HLA-A2 CAR (A2-CAR) generated by grafting the complementarity-determining regions (CDRs) of a human monoclonal anti-HLA-A2 antibody into the framework regions of the Herceptin 4D5 single-chain variable fragment and fusing it with a CD28-zeta signaling domain. The CDR-grafted A2-CAR maintained the specificity of the original antibody. We then generated HLA-A2 mono-specific human CAR Tregs either by deleting the endogenous T-cell receptor (TCR) via CRISPR/Cas9 and introducing the A2-CAR using lentiviral transduction or by directly integrating the CAR construct into the TCR alpha constant locus using homology-directed repair. These A2-CAR+TCRdeficient human Tregs maintained both Treg phenotype and function in vitro. Moreover, they selectively accumulated in HLA-A2-expressing islets transplanted from either HLA-A2 transgenic mice or deceased human donors. A2-CAR+TCRdeficient Tregs did not impair the function of these HLA-A2+ islets, whereas similarly engineered A2-CAR+TCRdeficientCD4+ conventional T cells rejected the islets in less than 2 weeks. A2-CAR+TCRdeficient Tregs delayed graft-versus-host disease only in the presence of HLA-A2, expressed either by co-transferred peripheral blood mononuclear cells or by the recipient mice. Altogether, we demonstrate that genome-engineered mono-antigen-specific A2-CAR Tregs localize to HLA-A2-expressing grafts and exhibit antigen-dependent in vivo suppression, independent of TCR expression. These approaches may be applied towards developing precision Treg cell therapies for transplant tolerance.

scholarly journals CD4-Negative Cells Bind Human Immunodeficiency Virus Type 1 and Efficiently Transfer Virus to T Cells

2000 ◽  
Vol 74 (18) ◽  
pp. 8550-8557 ◽  
Author(s):  
Gene G. Olinger ◽  
Mohammed Saifuddin ◽  
Gregory T. Spear
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Mononuclear Cells ◽  
Cell Types ◽  
Virus Binding ◽  
Peripheral Blood Mononuclear ◽  
Human Immunodeficiency Virus Strain ◽  
Immunodeficiency Virus

ABSTRACT The ability of human immunodeficiency virus strain MN (HIVMN), a T-cell line-adapted strain of HIV, and X4 and R5 primary isolates to bind to various cell types was investigated. In general, HIVMN bound to cells at higher levels than did the primary isolates. Virus bound to both CD4-positive (CD4+) and CD4-negative (CD4−) cells, including neutrophils, Raji cells, tonsil mononuclear cells, erythrocytes, platelets, and peripheral blood mononuclear cells (PBMC), although virus bound at significantly higher levels to PBMC. However, there was no difference in the amount of HIV that bound to CD4-enriched or CD4-depleted PBMC. Virus bound to CD4− cells was up to 17 times more infectious for T cells in cocultures than was the same amount of cell-free virus. Virus bound to nucleated cells was significantly more infectious than virus bound to erythrocytes or platelets. The enhanced infection of T cells by virus bound to CD4− cells was not due to stimulatory signals provided by CD4− cells or infection of CD4− cells. However, anti-CD18 antibody substantially reduced the enhanced virus replication in T cells, suggesting that virus that bound to the surface of CD4−cells is efficiently passed to CD4+ T cells during cell-cell adhesion. These studies show that HIV binds at relatively high levels to CD4− cells and, once bound, is highly infectious for T cells. This suggests that virus binding to the surface of CD4− cells is an important route for infection of T cells in vivo.

scholarly journals Intrinsic Susceptibility of Rhesus Macaque Peripheral CD4+ T Cells to Simian Immunodeficiency Virus In Vitro Is Predictive of In Vivo Viral Replication

2000 ◽  
Vol 74 (20) ◽  
pp. 9388-9395 ◽  
Author(s):  
Simoy Goldstein ◽  
Charles R. Brown ◽  
Houman Dehghani ◽  
Jeffrey D. Lifson ◽  
Vanessa M. Hirsch
Keyword(s):  
T Cell ◽  
Simian Immunodeficiency Virus ◽  
Rank Order ◽  
Rhesus Macaques ◽  
Target Cells ◽  
Plasma Viremia ◽  
Immunodeficiency Virus ◽  
Siv Infection

ABSTRACT Previous studies with simian immunodeficiency virus (SIV) infection of rhesus macaques suggested that the intrinsic susceptibility of peripheral blood mononuclear cells (PBMC) to infection with SIV in vitro was predictive of relative viremia after SIV challenge. The present study was conducted to evaluate this parameter in a well-characterized cohort of six rhesus macaques selected for marked differences in susceptibility to SIV infection in vitro. Rank order relative susceptibility of PBMC to SIVsmE543-3-infection in vitro was maintained over a 1-year period of evaluation. Differential susceptibility of different donors was maintained in CD8+T-cell-depleted PBMC, macrophages, and CD4+ T-cell lines derived by transformation of PBMC with herpesvirus saimiri, suggesting that this phenomenon is an intrinsic property of CD4+target cells. Following intravenous infection of these macaques with SIVsmE543-3, we observed a wide range in plasma viremia which followed the same rank order as the relative susceptibility established by in vitro studies. A significant correlation was observed between plasma viremia at 2 and 8 weeks postinoculation and in vitro susceptibility (P < 0.05). The observation that the two most susceptible macaques were seropositive for simian T-lymphotropic virus type 1 may suggests a role for this viral infection in enhancing susceptibility to SIV infection in vitro and in vivo. In summary, intrinsic susceptibility of CD4+ target cells appears to be an important factor influencing early virus replication patterns in vivo that should be considered in the design and interpretation of vaccine studies using the SIV/macaque model.

scholarly journals Novel, Live Attenuated Simian Immunodeficiency Virus Constructs Containing Major Deletions in Leader RNA Sequences

2001 ◽  
Vol 75 (6) ◽  
pp. 2776-2785 ◽  
Author(s):  
Yongjun Guan ◽  
James B. Whitney ◽  
Chen Liang ◽  
Mark A. Wainberg
Keyword(s):  
Tissue Culture ◽  
Simian Immunodeficiency Virus ◽  
Mononuclear Cells ◽  
Polyacrylamide Gel Electrophoresis ◽  
Wild Type Virus ◽  
Replication Capacity ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus

ABSTRACT We have constructed a series of simian immunodeficiency virus (SIV) mutants containing deletions within a 97-nucleotide (nt) region of the leader sequence. Deletions in this region markedly decreased the replication capacity in tissue culture, i.e., in both the C8166 and CEMx174 cell lines, as well as in rhesus macaque peripheral blood mononuclear cells. In addition, these deletions adversely affected the packaging of viral genomic RNA into virions, the processing of Gag precursor proteins, and patterns of viral proteins in virions, as assessed by biochemical labeling and polyacrylamide gel electrophoresis. Different levels of attenuation were achieved by varying the size and position of deletions within this 97-nt region, and among a series of constructs that were generated, it was possible to rank in vitro virulence relative to that of wild-type virus. In all of these cases, the most severe impact on viral replication was observed when the deletions that were made were located at the 3′ rather than 5′ end of the leader region. The potential of viral reversion over protracted periods was investigated by repeated viral passage in CEMx174 cells. The results showed that several of these constructs showed no signs of reversion after more than 6 months in tissue culture. Thus, a series of novel, attenuated SIV constructs have been developed that are significantly impaired in replication capacity yet retain all viral genes. One of these viruses, termed SD4, may be appropriate for study with rhesus macaques, in order to determine whether reversions will occur in vivo and to further study this virus as a candidate for attenuated vaccination.

scholarly journals Changes in Human Immunodeficiency Virus Type 1 Envelope Glycoproteins Responsible for the Pathogenicity of a Multiply Passaged Simian-Human Immunodeficiency Virus (SHIV-HXBc2)

1999 ◽  
Vol 73 (2) ◽  
pp. 976-984 ◽  
Author(s):  
Mark Cayabyab ◽  
Gunilla B. Karlsson ◽  
Bijan A. Etemad-Moghadam ◽  
Wolfgang Hofmann ◽  
Tavis Steenbeke ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocyte ◽  
Mononuclear Cells ◽  
Rhesus Macaques ◽  
Envelope Glycoproteins ◽  
Peripheral Blood Mononuclear ◽  
Lymphocyte Depletion ◽  
Immunodeficiency Virus

ABSTRACT In vivo passage of a poorly replicating, nonpathogenic simian-human immunodeficiency virus (SHIV-HXBc2) generated an efficiently replicating virus, KU-1, that caused rapid CD4+T-lymphocyte depletion and AIDS-like illness in monkeys (S. V. Joag, Z. Li, L. Foresman, E. B. Stephens, L.-J. Zhao, I. Adany, D. M. Pinson, H. M. McClure, and O. Narayan, J. Virol. 70:3189–3197, 1996). The env gene of the KU-1 virus was used to create a molecularly cloned virus, SHIV-HXBc2P 3.2, that differed from a nonpathogenic SHIV-HXBc2 virus in only 12 envelope glycoprotein residues. SHIV-HXBc2P 3.2 replicated efficiently and caused rapid and persistent CD4+ T-lymphocyte depletion in inoculated rhesus macaques. Compared with the envelope glycoproteins of the parental SHIV-HXBc2, the SHIV-HXBc2P 3.2 envelope glycoproteins supported more efficient infection of rhesus monkey peripheral blood mononuclear cells. Both the parental SHIV-HXBc2 and the pathogenic SHIV-HXBc2P 3.2 used CXCR4 but none of the other seven transmembrane segment receptors tested as a second receptor. Compared with the parental virus, viruses with the SHIV-HXBc2P 3.2 envelope glycoproteins were more resistant to neutralization by soluble CD4 and antibodies. Thus, changes in the envelope glycoproteins account for the ability of the passaged virus to deplete CD4+ T lymphocytes rapidly and specify increased replicative capacity and resistance to neutralization.

scholarly journals Kinetics of Replication of a Partially Attenuated Virus and of the Challenge Virus during a Three-Year Intersubtype Feline Immunodeficiency Virus Superinfection Experiment in Cats

1999 ◽  
Vol 73 (2) ◽  
pp. 1518-1527 ◽  
Author(s):  
Mauro Pistello ◽  
Donatella Matteucci ◽  
Giancarlo Cammarota ◽  
Paola Mazzetti ◽  
Simone Giannecchini ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Mononuclear Cells ◽  
Acute Infection ◽  
Low Grade ◽  
Peripheral Blood Mononuclear ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Attenuated Virus

ABSTRACT The effects of preinfecting cats with a partially attenuated feline immunodeficiency virus (FIV) on subsequent infection with a fully virulent FIV belonging to a different subtype were investigated. Eight specific-pathogen-free cats were preinfected with graded doses of a long-term in vitro-cultured cell-free preparation of FIV Petaluma (FIV-P, subtype A). FIV-P established a low-grade or a silent infection in the inoculated animals. Seven months later, the eight preinfected cats and two uninfected cats were challenged with in vivo-grown FIV-M2 (subtype B) and periodically monitored for immunological and virological status. FIV-P-preinfected cats were not protected from acute infection by FIV-M2, and the sustained replication of this virus was accompanied by a reduction of FIV-P viral loads in the peripheral blood mononuclear cells and plasma. However, from 2 years postchallenge (p.c.) until 3 years p.c., when the experiment was terminated, preinfected cats exhibited reduced total viral burdens, and some also exhibited a diminished decline of circulating CD4+ T lymphocytes relative to control cats infected with FIV-M2 alone. Interestingly, most of the virus detected in challenged cats at late times p.c. was of FIV-P origin, indicating that the preinfecting, attenuated virus had become largely predominant. By the end of follow-up, two challenged cats had no FIV-M2 detectable in the tissues examined. The possible mechanisms underlying the interplay between the two viral populations are discussed.

High levels of thyroid hormone impair regulatory T cells function via reduced PD-1 expression

2021 ◽  
Author(s):  
Yi Zhong ◽  
Ting-Ting Lu ◽  
Xiao-Mei Liu ◽  
Bing-Li Liu ◽  
Yun Hu ◽  
...  
Keyword(s):  
T Cells ◽  
Thyroid Hormone ◽  
Regulatory T Cells ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Dependent Manner ◽  
Peripheral Blood Mononuclear

Abstract Context Regulatory T cells (Tregs) dysfunction plays an important role in the development and progression of Graves’ disease (GD). Programmed cell death 1 (PD-1) prompts FoxP3 in Tregs expression and enhances the suppressive activity of Tregs. Whether abnormal expression of PD-1 contributes to the breakdown of Tregs and the role of thyroid hormone in the PD-1 expression of Tregs in GD remain substantially undefined. Objective To evaluate the role of PD-1 in Tregs function and triiodothyronine (T3) in PD-1 expression in patients with GD and mice treated with T3. Methods We recruited 30 patients with GD and 30 healthy donors. PD-1 expression in Tregs and Tregs function were determined. To evaluate the effects of thyroid hormone on PD-1 expression in Tregs, we used T3 for the treatment of human peripheral blood mononuclear cells (PBMCs). We then treated mice with T3 to confirm the effect of thyroid hormone on PD-1 expression in Tregs and Tregs function in vivo. Results PD-1 expression in Tregs and the suppressive function of Tregs significantly decreased in patients with GD. T3 reduced PD-1 expression in human Tregs in a concentration- and time-dependent manner in vitro. High levels of circulating T3 reduced PD-1 expression in Tregs, impaired Tregs function, and disrupted T-helper cell (Th1 and Th2) balance in mice treated with T3. Conclusions Tregs dysfunction in GD patients might be due to down-regulation of PD-1 expression in Tregs induced by high levels of serum T3.

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