scholarly journals Virus and CTL dynamics in the extra-follicular and follicular tissue compartments in SIV-infected macaques

2018 ◽  
Author(s):  
Dominik Wodarz ◽  
Pamela J. Skinner ◽  
David N. Levy ◽  
Elizabeth Connick
Keyword(s):  
Experimental Data ◽  
Cytotoxic T Lymphocytes ◽  
Lymphoid Tissue ◽  
Productive Infection ◽  
Virus Load ◽  
Virus Control ◽  
Infected Cells ◽  
Cd8 Cell ◽  
Expansion Model ◽  
Tissue Compartments

AbstractData from SIV-infected macaques indicate that virus-specific cytotoxic T lymphocytes (CTL) are mostly present in the extrafollicular (EF) compartment of the lymphoid tissue, with reduced homing to the follicular (F) site. This contributes to the majority of the virus being present in the follicle and represents a barrier to virus control. Using mathematical models, we investigate these dynamics. Two models are analyzed. The first assumes that CTL can only become stimulated and expand in the extra-follicular compartment, with migration accounting for the presence of CTL in the follicle. In the second model, follicular CTL can also undergo antigen-induced expansion. Consistent with experimental data, both models predict increased virus compartmentalization in the presence of stronger CTL responses and lower virus loads, and a more pronounced rise of extra-follicular compared to follicular virus during CD8 cell depletion experiments. The models, however, differ in other aspects. The follicular expansion model results in dynamics that promote the clearance of productive infection in the extrafollicular site, with any productively infected cells found being the result of immigration from the follicle. This is not observed in the model without follicular CTL expansion. The models further predict different consequences of introducing engineered, follicular-homing CTL, which has been proposed as a therapeutic means to improve virus control. Without follicular CTL expansion, this is predicted to result in a reduction of virus load in both compartments. The follicular CTL expansion model, however, makes the counter-intuitive prediction that addition of F-homing CTL not only results in a reduction of follicular virus load, but also in an increase in extrafollicular virus replication. These predictions remain to be experimentally tested, which will be relevant for distinguishing between models and for understanding how therapeutic introduction of F-homing CTL might impact the overall dynamics of the infection.

scholarly journals Highly Productive Infection with Pseudotyped Human Immunodeficiency Virus Type 1 (HIV-1) Indicates No Intracellular Restrictions to HIV-1 Replication in Primary Human Astrocytes

2001 ◽  
Vol 75 (17) ◽  
pp. 7925-7933 ◽  
Author(s):  
Mario Canki ◽  
Janice Ngee Foong Thai ◽  
Wei Chao ◽  
Anuja Ghorpade ◽  
Mary Jane Potash ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Productive Infection ◽  
Human Astrocytes ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Virus Expression ◽  
Hiv 1

ABSTRACT Human astrocytes can be infected with human immunodeficiency virus type 1 (HIV-1) in vitro and in vivo, but, in contrast to T lymphocytes and macrophages, virus expression is inefficient. To investigate the HIV-1 life cycle in human fetal astrocytes, we infected cells with HIV-1 pseudotyped with envelope glycoproteins of either amphotropic murine leukemia virus or vesicular stomatitis virus. Infection by both pseudotypes was productive and long lasting and reached a peak of 68% infected cells and 1.7 μg of viral p24 per ml of culture supernatant 7 days after virus inoculation and then continued with gradually declining levels of virus expression through 7 weeks of follow-up. This contrasted with less than 0.1% HIV-1 antigen-positive cells and 400 pg of extracellular p24 per ml at the peak of astrocyte infection with native HIV-1. Cell viability and growth kinetics were similar in infected and control cells. Northern blot analysis revealed the presence of major HIV-1 RNA species of 9, 4, and 2 kb in astrocytes exposed to pseudotyped (but not wild-type) HIV-1 at 2, 14, and 28 days after infection. Consistent with productive infection, the 9- and 4-kb viral transcripts in astrocytes infected by pseudotyped HIV-1 were as abundant as the 2-kb mRNA during 4 weeks of follow-up, and both structural and regulatory viral proteins were detected in infected cells by immunoblotting or cell staining. The progeny virus released by these cells was infectious. These results indicate that the major barrier to HIV-1 infection of primary astrocytes is at virus entry and that astrocytes have no intrinsic intracellular restriction to efficient HIV-1 replication.

scholarly journals Patterns of accumulation of miRNAs encoded by herpes simplex virus during productive infection, latency, and on reactivation

2014 ◽  
Vol 112 (1) ◽  
pp. E49-E55 ◽  
Author(s):  
Te Du ◽  
Zhiyuan Han ◽  
Guoying Zhou ◽  
Bernard Roizman
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Cultured Cells ◽  
Viral Gene Expression ◽  
The Body ◽  
Productive Infection ◽  
Viral Gene ◽  
Infected Cells ◽  
Simplex Virus ◽  
Portal Of Entry

The key events in herpes simplex virus (HSV) infections are (i) replication at a portal of entry into the body modeled by infection of cultured cells; (ii) establishment of a latent state characterized by a sole latency-associated transcript and microRNAs (miRNAs) modeled in murine peripheral ganglia 30 d after inoculation; and (iii) reactivation from the latent state modeled by excision and incubation of ganglia in medium containing anti-NGF antibody for a timespan of a single viral replicative cycle. In this report, we examine the pattern of synthesis and accumulation of 18 HSV-1 miRNAs in the three models. We report the following: (i) H2-3P, H3-3P, H4-3P, H5-3P, H6-3P, and H7-5P accumulated in ganglia harboring latent virus. All but H4-3P were readily detected in productively infected cells, and most likely they originate from three transcriptional units. (ii) H8-5P, H15, H17, H18, H26, and H27 accumulated during reactivation. Of this group, only H26 and H27 could be detected in productively infected cells. (iii) Of the 18 we have examined, only 10 miRNAs were found to accumulate above background levels in productively infected cells. The disparity in the accumulation of miRNAs in cell culture and during reactivation may reflect differences in the patterns of regulation of viral gene expression during productive infection and during reactivation from the latent state.

scholarly journals The gammaherpesvirus 68 viral cyclin facilitates reactivation by promoting latent gene expression

2019 ◽  
Author(s):  
Brian F Niemeyer ◽  
Joy E Gibson ◽  
Jennifer N Berger ◽  
Lauren M Oko ◽  
Eva Medina ◽  
...  
Keyword(s):  
Gene Expression ◽  
Critical Role ◽  
Productive Infection ◽  
Viral Gene ◽  
Cellular Distribution ◽  
Viral Cyclin ◽  
Latently Infected ◽  
Infected Cells ◽  
Virally Encoded ◽  
The Impact

AbstractGammaherpesviruses establish life-long infections within their host and have been shown to be the causative agents of devastating malignancies. Chronic infection within the host is mediated through cycles of transcriptionally quiescent stages of latency with periods of reactivation into more active lytic and productive infection. The mechanisms that regulate reactivation from latency remain poorly understood. Previously, we defined a critical role for the viral cyclin in promoting reactivation from latency. Disruption of the viral cyclin had no impact on the frequency of cells containing viral genome during latency, yet it remains unclear whether the viral cyclin influences latently infected cells in a qualitative manner. To define the impact of the viral cyclin on latent gene expression, we utilized a viral cyclin deficient variant expressing a LANA-beta-lactamase fusion protein (LANA::βla), to enumerate both the cellular distribution and frequency of latent gene expression. Disruption of the viral cyclin did not affect the cellular distribution of latently infected cells, but did result in a significant decrease in the frequency of cells that expressed LANA::βla across multiple tissues and in both immunocompetent and immunodeficient hosts. Strikingly, whereas the cyclin-deficient virus had a reactivation defect in bulk culture, sort purified cyclin-deficient LANA::βla expressing cells were fully capable of reactivation. These data emphasize that the γHV68 latent reservoir is comprised of at least two distinct stages of infection characterized by differential latent gene expression, and that a primary function of the viral cyclin is to promote latent gene expression within infected cells in vivo.AUTHOR SUMMARYGammaherpesviruses are ubiquitous viruses with oncogenic potential that establish latency for the life of the host. These viruses can emerge from latency through reactivation, a process that is controlled by the immune system. Control of viral latency and reactivation is thought to be critical to prevent γHV-associated disease. This study focuses on a virally-encoded cyclin that is required for reactivation from latency. By characterizing how the viral cyclin influences latent infection in pure cell populations, we find that the viral cyclin has a vital role in promoting viral gene expression during latency. This work provides new insight into the function of a virally encoded cyclin in promoting reactivation from latency.

scholarly journals Expression of the Pseudorabies Virus Latency-Associated Transcript Gene during Productive Infection of Cultured Cells

1999 ◽  
Vol 73 (12) ◽  
pp. 9781-9788 ◽  
Author(s):  
Ling Jin ◽  
Gail Scherba
Keyword(s):  
Gene Expression ◽  
Pseudorabies Virus ◽  
Cultured Cells ◽  
Initiation Site ◽  
Early Gene ◽  
Productive Infection ◽  
Virus Latency ◽  
Infected Cells ◽  
Transcript Gene

ABSTRACT Like other alphaherpesviruses, pseudorabies virus (PrV) exhibits restricted gene expression during latency. These latency-associated transcripts (LATs) are derived from the region located within 0.69 to 0.77 map units of the viral genome. However, the presence of such viral RNAs during a productive infection has not been described. Although several transcripts originating between 0.706 to 0.737 map units have been detected in PrV-infected cultured cells, their relationship to the LATs has not been examined. Therefore, to determine if any correlation exists between PrV LAT gene expression in the natural and laboratory systems, transcription from the LAT gene region during lytic infection of cultured neuronal and nonneuronal cells was evaluated. A Northern blot assay using single-stranded RNA probes complementary to the spliced in vivo 8.4-kb largest latency transcript (LLT) detected 1.0-, 2.0-, and 8.0-kb poly(A) RNAs in all PrV-infected cells lines. The 1.0- and 8.0-kb transcripts partially overlapped the first and second exons of the LLT, respectively. In contrast, portions of both LLT exons comprised the 2.0-kb RNA sequence, which lacked the same intron as the LLT. Generation of this transcript began about 243 bp downstream of the LLT initiation site and terminated near the junction of BamHI fragments 8′ and 8. Its synthesis was inhibited by cycloheximide but not by cytosine β-d-arabinofuranoside, which suggests that the 2.0-kb RNA is not an immediate-early gene product. Thus, although the PrV LAT gene is transcriptionally active during a productive infection of cultured cells, the resulting RNAs are distinctive from the LLT.

scholarly journals A Human Herpesvirus 7 Glycoprotein, U21, Diverts Major Histocompatibility Complex Class I Molecules to Lysosomes

2001 ◽  
Vol 75 (24) ◽  
pp. 12347-12358 ◽  
Author(s):  
Amy W. Hudson ◽  
Peter M. Howley ◽  
Hidde L. Ploegh
Keyword(s):  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Cytotoxic T Lymphocytes ◽  
Human Herpesvirus ◽  
Class I ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Infected Cells ◽  
Immune Detection

ABSTRACT All members of the herpesvirus family persist in their host throughout life. In doing so, herpesviruses exploit a surprising number of different strategies to evade the immune system. Human herpesvirus 7 (HHV-7) is a relatively recently discovered member of the herpesvirus family, and little is known about how it escapes immune detection. Here we show that HHV-7 infection results in premature degradation of major histocompatibility complex class I molecules. We identify and characterize a protein from HHV-7, U21, that binds to and diverts properly folded class I molecules to a lysosomal compartment. Thus, U21 is likely to function in the normal course of HHV-7 infection to downregulate surface class I molecules and prevent recognition of infected cells by cytotoxic T lymphocytes.

scholarly journals Polymorphism and Structural Maturation of Bunyamwera Virus in Golgi and Post-Golgi Compartments

2003 ◽  
Vol 77 (2) ◽  
pp. 1368-1381 ◽  
Author(s):  
Iñigo J. Salanueva ◽  
Reyes R. Novoa ◽  
Pilar Cabezas ◽  
Carmen López-Iglesias ◽  
José L. Carrascosa ◽  
...  
Keyword(s):  
Golgi Complex ◽  
Vero Cells ◽  
Productive Infection ◽  
Tubular Structures ◽  
Enveloped Viruses ◽  
Golgi Stack ◽  
Golgi Region ◽  
Viral Particles ◽  
Infected Cells ◽  
Bunyamwera Virus

ABSTRACT The Golgi apparatus is the assembly site for a number of complex enveloped viruses. Using high-preservation methods for electron microscopy, we have detected two previously unknown maturation steps in the morphogenesis of Bunyamwera virus in BHK-21 cells. The first maturation takes place inside the Golgi stack, where annular immature particles transform into dense, compact structures. Megalomicin, a drug that disrupts the trans side of the Golgi complex, reversibly blocks transformation, showing that a functional trans-Golgi is needed for maturation. The second structural change seems to take place during the egress of viral particles from cells, when a coat of round-shaped spikes becomes evident. A fourth viral assembly was detected in infected cells: rigid tubular structures assemble in the Golgi region early in infection and frequently connect with mitochondria. In Vero cells, the virus induces an early and spectacular fragmentation of intracellular membranes while productive infection progresses. Assembly occurs in fragmented Golgi stacks and generates tubular structures, as well as the three spherical viral forms. These results, together with our previous studies with nonrelated viruses, show that the Golgi complex contains key factors for the structural transformation of a number of enveloped viruses that assemble intracellularly.

scholarly journals The Hypervariable Immunodominant NP418-426 Epitope from the Influenza A Virus Nucleoprotein Is Recognized by Cytotoxic T Lymphocytes with High Functional Avidity

2006 ◽  
Vol 80 (12) ◽  
pp. 6024-6032 ◽  
Author(s):  
Adrianus C. M. Boon ◽  
Gerrie de Mutsert ◽  
Ron A. M. Fouchier ◽  
Albert D. M. E. Osterhaus ◽  
Guus F. Rimmelzwaan
Keyword(s):  
T Lymphocytes ◽  
Influenza A Virus ◽  
Cytotoxic T Lymphocytes ◽  
Influenza A ◽  
Mononuclear Cells ◽  
Influenza Viruses ◽  
Functional Avidity ◽  
Human Virus ◽  
Ctl Epitopes ◽  
Infected Cells

ABSTRACT Recently it was shown that influenza A viruses can accumulate mutations in epitopes associated with escape from recognition by human virus-specific cytotoxic T lymphocytes (CTL). It is unclear what drives diversification of CTL epitopes and why certain epitopes are variable and others remain conserved. It has been shown that simian immunodeficiency virus-specific CTL that recognize their epitope with high functional avidity eliminate virus-infected cells efficiently and drive diversification of CTL epitopes. T-cell functional avidity is defined by the density of major histocompatibility complex class I peptide complexes required to activate specific CTL. We hypothesized that functional avidity of CTL contributes to epitope diversification and escape from CTL also for influenza viruses. To test this hypothesis, the functional avidity of polyclonal CTL populations specific for nine individual epitopes was determined. To this end, peripheral blood mononuclear cells from HLA-A- and -B-genotyped individuals were stimulated in vitro with influenza virus-infected cells to allow expansion of virus-specific CTL, which were used to determine the functional avidity of CTL specific for nine individual epitopes in enzyme-linked immunospot assays. We found that the functional avidity for the respective epitopes varied widely. Furthermore, the functional avidity of CTL specific for the hypervariable NP418-426 epitope was significantly higher than that of CTL recognizing other epitopes (P < 0.01). It was speculated that the high functional avidity of NP418-426-specific CTL was responsible for the diversification of this influenza A virus CTL epitope.

scholarly journals HSP70 and HSP90 Differentially Regulate Translocation of Extracellular Antigen to the Cytosol for Cross-Presentation

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Yu Kato ◽  
Chiaki Kajiwara ◽  
Ikuo Ishige ◽  
Shusaku Mizukami ◽  
Chihiro Yamazaki ◽  
...  
Keyword(s):  
Cytotoxic T Lymphocytes ◽  
Type I Diabetes ◽  
Hsp90 Inhibitor ◽  
Type I ◽  
Marked Contrast ◽  
Cross Presentation ◽  
Essential Step ◽  
Endosomal Membranes ◽  
Infected Cells ◽  
Hsp70 Inhibitors

Antigens (Ag) from cancer or virus-infected cells must be internalized by dendritic cells (DCs) to be presented to CD8+T cells, which eventually differentiate into Ag-specific cytotoxic T lymphocytes (CTLs) that destroy cancer cells and infected cells. This pathway is termed cross-presentation and is also implicated as an essential step in triggering autoimmune diseases such as Type I diabetes. Internalized Ag locates within endosomes, followed by translocation through a putative pore structure spanning endosomal membranes into the cytosol, where it is degraded by the proteasome to generate antigen peptides. During translocation, Ag is believed to be unfolded since the pore size is too narrow to accept native Ag structure. Here, we show that paraformaldehyde-fixed, structurally inflexible Ag is less efficient in cross-presentation because of diminished translocation into the cytosol, supporting the “unfolded Ag” theory. We also show that HSP70 inhibitors block both endogenous and cross-presentation. ImageStream analysis revealed that the inhibition in cross-presentation is not due to blocking of Ag translocation because a HSP70 inhibitor rather facilitates the translocation, which is in marked contrast to the effect of an HSP90 inhibitor that blocks Ag translocation. Our results indicate that Ag translocation to the cytosol in cross-presentation is differentially regulated by HSP70 and HSP90.

scholarly journals R5 Variants of Human Immunodeficiency Virus Type 1 Preferentially Infect CD62L− CD4+ T Cells and Are Potentially Resistant to Nucleoside Reverse Transcriptase Inhibitors

2006 ◽  
Vol 80 (2) ◽  
pp. 854-865 ◽  
Author(s):  
Françoise Gondois-Rey ◽  
Angelique Biancotto ◽  
Marcelo Antonio Fernandez ◽  
Lise Bettendroffer ◽  
Jana Blazkova ◽  
...  
Keyword(s):  
T Cells ◽  
Reverse Transcriptase ◽  
Lymphoid Tissue ◽  
Ex Vivo ◽  
Productive Infection ◽  
Reverse Transcriptase Inhibitors ◽  
Hla Dr ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The persistence of human immunodeficiency virus type 1 (HIV-1) in memory CD4+ T cells is a major obstacle to the eradication of the virus with current antiretroviral therapy. Here, we investigated the effect of the activation status of CD4+ T cells on the predominance of R5 and X4 HIV-1 variants in different subsets of CD4+ T cells in ex vivo-infected human lymphoid tissues and peripheral blood mononuclear cells (PBMCs). In these cell systems, we examined the sensitivity of HIV replication to reverse transcriptase inhibitors. We demonstrate that R5 HIV-1 variants preferentially produced productive infection in HLA-DR− CD62L− CD4+ T cells. These cells were mostly in the G1b phase of the cell cycle, divided slowly, and expressed high levels of CCR5. In contrast, X4 HIV-1 variants preferentially produced productive infection in activated HLA-DR+ CD62L+ CD4+ T cells, which expressed high levels of CXCR4. The abilities of the nucleoside reverse transcriptase inhibitors (NRTI) zidovudine and lamivudine to stop HIV-1 replication were 20 times greater in activated T cells than in slowly dividing HLA-DR− CD62L− CD4+ T cells. This result, demonstrated both in a highly physiologically relevant ex vivo lymphoid tissue model and in PBMCs, correlated with higher levels of thymidine kinase mRNA in activated than in slowly dividing HLA-DR− CD62L− CD4+ T cells. The non-NRTI nevirapine was equally efficient in both cell subsets. The lymphoid tissue and PBMC-derived cell systems represent well-defined models which could be used as new tools for the study of the mechanism of resistance to HIV-1 inhibitors in HLA-DR− CD62L− CD4+ T cells.

scholarly journals CD8+ Lymphocytes Do Not Mediate Protection against Acute Superinfection 20 Days after Vaccination with a Live Attenuated Simian Immunodeficiency Virus

2005 ◽  
Vol 79 (19) ◽  
pp. 12264-12272 ◽  
Author(s):  
Richard Stebbings ◽  
Neil Berry ◽  
Herman Waldmann ◽  
Pru Bird ◽  
Geoff Hale ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
T Lymphocytes ◽  
Simian Immunodeficiency Virus ◽  
Cytotoxic T Lymphocytes ◽  
T Lymphocyte ◽  
Lymphoid Tissue ◽  
Human Immunoglobulin ◽  
Wild Type ◽  
Lymphocyte Depletion ◽  
Immunodeficiency Virus

ABSTRACT In order to test the hypothesis that CD8+ cytotoxic T lymphocytes mediate protection against acute superinfection, we depleted >99% of CD8+ lymphocytes in live attenuated simian immunodeficiency virus macC8 (SIVmacC8) vaccinees from the onset of vaccination, maintained that depletion for 20 days, and then challenged with pathogenic, wild-type SIVmacJ5. Vaccinees received 5 mg per kg of humanized anti-CD8 monoclonal antibody (MAb) 1 h before inoculation, followed by the same dose again on days 3, 7, 10, 13, and 17. On day 13, peripheral CD8+ T lymphocytes were >99% depleted in three out of four anti-CD8 MAb-treated vaccinees. At this time attenuated SIVmacC8 viral RNA loads in anti-CD8 MAb-treated vaccinees were significantly higher than control vaccinees treated contemporaneously with nonspecific human immunoglobulin. Lymphoid tissue CD8+ T lymphocyte depletion was >99% in three out of four anti-CD8 MAb-treated vaccinees on the day of wild-type SIVmacJ5 challenge. All four control vaccinees and three out of four anti-CD8 MAb-treated vaccinees were protected against detectable superinfection with wild-type SIVmacJ5. Although superinfection with wild-type SIVmacJ5 was detected at postmortem in a single anti-CD8 MAb-treated vaccinee, this did not correlate with the degree of preceding CD8+ T lymphocyte depletion. Clearance of attenuated SIVmacC8 viremia coincided with recovery of normal CD8+ T lymphocyte counts between days 48 and 76. These results support the view that cytotoxic T lymphocytes are important for host-mediated control of SIV primary viremia but do not indicate a central role in protection against acute superinfection conferred by inoculation with live attenuated SIV.

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