scholarly journals Differential Cell Tropism of Feline Immunodeficiency Virus Molecular Clones In Vivo

1999 ◽  
Vol 73 (4) ◽  
pp. 2596-2603 ◽  
Author(s):  
Gregg A. Dean ◽  
Sunee Himathongkham ◽  
Ellen E. Sparger
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Mononuclear Cells ◽  
Lymphocyte Subsets ◽  
Cell Tropism ◽  
Replication Efficiency ◽  
Proviral Dna ◽  
Immunodeficiency Virus ◽  
Differential Cell

ABSTRACT Independent studies have demonstrated different cell tropisms for molecular clones of feline immunodeficiency virus (FIV). In this report, we examined three clones, FIV-pF34, FIV-14, and FIV-pPPR, for replication in Crandell feline kidney (CrFK) cells, feline peripheral blood mononuclear cells (PBMC), and feline macrophage cultures. Importantly, cell tropism for these three clones was also examined in vivo. FIV-pF34 replication was efficient in CrFK cells but severely restricted in PBMC, whereas replication of FIV-pPPR was vigorous in PBMC but severely restricted in CrFK cells. FIV-14 replication was productive in both CrFK cells and PBMC. Interestingly, all three molecular clones replicated with similar efficiencies in primary feline monocyte-derived macrophages. In vivo, FIV-pF34 proved least efficient for establishing persistent infection, and proviral DNA when detectable, was localized predominately to nonlymphoid cell populations (macrophages). FIV-pPPR proved most efficient for induction of a persistent viremia in vivo, and proviral DNA was localized predominately in CD4+ and CD8+ lymphocyte subsets. FIV-14 inoculation of cats resulted in an infection characterized by seroconversion and localization of proviral DNA in CD4+ lymphocytes only. Results of this study on diverse FIV molecular clones revealed that in vitro replication efficiency of an FIV isolate in PBMC directly correlated with replication efficiency in vivo, whereas proficiency for replication in macrophages in vitro was not predictive for replication potential in vivo. Also, infection of both CD4+ and CD8+ lymphocyte subsets was associated with higher virus load in vivo. Results of the studies on these three FIV clones, which exhibited differential cell tropism, indicated a correlation between in vitro and in vivo cell tropism and virus replication.

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.

scholarly journals In Vivo Antiretroviral Activity of Stampidine in Chronically Feline Immunodeficiency Virus-Infected Cats

2003 ◽  
Vol 47 (4) ◽  
pp. 1233-1240 ◽  
Author(s):  
Fatih M. Uckun ◽  
Chun-Lin Chen ◽  
Peter Samuel ◽  
Sharon Pendergrass ◽  
T. K. Venkatachalam ◽  
...  
Keyword(s):  
Dose Level ◽  
Peripheral Blood Mononuclear Cells ◽  
Feline Immunodeficiency Virus ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Blood Mononuclear Cells ◽  
Antiretroviral Activity

ABSTRACT Here we report the antiretroviral activity of the experimental nucleoside reverse transcriptase inhibitor (NRTI) compound stampidine in cats chronically infected with feline immunodeficiency virus (FIV). Notably, a single oral bolus dose of 50 or 100 mg of stampidine per kg resulted in a transient ≥1-log decrease in the FIV load of circulating peripheral blood mononuclear cells in five of six FIV-infected cats and no side effects. A 4-week stampidine treatment course with twice-daily administration of hard gelatin capsules containing 25 to 100 mg of stampidine per kg was also very well tolerated by cats at cumulative dose levels as high as 8.4 g/kg and exhibited a dose-dependent antiretroviral effect. One of three cats treated at the 25-mg/kg dose level, three of three cats treated at the 50-mg/kg dose level, and three of three cats treated at the 100-mg/kg dose level (but none of three control cats treated with placebo pills) showed a therapeutic response, as evidenced by a ≥1-log reduction in the FIV load in peripheral blood mononuclear cells within 2 weeks. The previously documented in vitro and in vivo antiretroviral activity of stampidine against primary clinical human immunodeficiency virus type 1 isolates with genotypic and/or phenotypic NRTI resistance, together with its favorable animal toxicity profile, pharmacokinetics, and in vivo antiretroviral activity in FIV-infected cats, warrants further development of this promising new NRTI compound.

scholarly journals Feline Immunodeficiency Virus-Infected Cat Sera Associated with the Development of Broad Neutralization Resistance In Vivo Drive Similar Reversions In Vitro

2001 ◽  
Vol 75 (18) ◽  
pp. 8868-8873 ◽  
Author(s):  
Simone Giannecchini ◽  
Donatella Matteucci ◽  
Aldo Ferrari ◽  
Mauro Pistello ◽  
Mauro Bendinelli
Keyword(s):  
Tissue Culture ◽  
Feline Immunodeficiency Virus ◽  
Surface Glycoprotein ◽  
Virus Variant ◽  
Humoral Immune ◽  
Immunodeficiency Virus ◽  
Escape Mutants ◽  
Intervening Factors

ABSTRACT We previously reported that, upon reinoculation into cats, a neutralization-sensitive, tissue culture-adapted strain of feline immunodeficiency virus constantly reverted to the broad neutralization resistance typical of primary virus isolates and identified residue 481 in the V4 region of the surface glycoprotein as a key determinant of the reversion. Here, we found that well-characterized immune sera, obtained from cats in which such reversion had occurred, selected in tissue culture in favor of virus variants that also had a neutralization-resistant phenotype and had amino acid 481 changed, thus indicating that the host's humoral immune response is capable of driving the reversion in the absence of other intervening factors. In contrast, a second group of immune sera, elicited by a virus variant that had already reverted to neutralization resistance in independent cats, induced the emergence of escape mutants lacking broad neutralization resistance and neutralized fewer virus variants. It is proposed that the viral variants used to produce the two sets of sera may have generated different antibody repertoires.

scholarly journals In Vitro Activation of Feline Immunodeficiency Virus in Ramified Microglial Cells from Asymptomatically Infected Cats

2001 ◽  
Vol 75 (17) ◽  
pp. 8090-8095 ◽  
Author(s):  
Andreas Hein ◽  
Jean-Pierre Martin ◽  
Rüdiger Dörries
Keyword(s):  
Central Nervous System ◽  
Tissue Culture ◽  
Nervous System ◽  
Feline Immunodeficiency Virus ◽  
Mononuclear Cells ◽  
Central Nervous System Infection ◽  
Microglial Cells ◽  
Cell Contact ◽  
Immunodeficiency Virus

ABSTRACT Intravenous infection of cats with feline immunodeficiency virus was used as a model system to study activation of virus replication in brain-resident microglial cells in vitro. Virus release by ramified microglial cells isolated from subclinically infected animals was detectable in cell-free tissue culture supernatant only by reverse transcription and nested PCR of gag-specific RNA sequences and not by virion-associated reverse transcriptase activity. In contrast, cocultivation of in vivo-infected microglial cells with mitogen-activated peripheral blood mononuclear cells (PBMC) regularly allows detection of high virus yields in cell-free tissue culture fluid. Besides uptake and multiplication of microglia-derived virus in PBMC, release of virus from microglia is stimulated by cell contact with PBMC. The data suggest that T lymphocytes patrolling the central nervous system could reactivate the semilatent state of lentiviruses in microglial cells in the course of clinically silent central nervous system infection.

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 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 Response of Simian Immunodeficiency Virus to the Novel Nucleoside Reverse Transcriptase Inhibitor 4′-Ethynyl-2-Fluoro-2′-DeoxyadenosineIn VitroandIn Vivo

2012 ◽  
Vol 56 (9) ◽  
pp. 4707-4712 ◽  
Author(s):  
Michael Murphey-Corb ◽  
Premeela Rajakumar ◽  
Heather Michael ◽  
Julia Nyaundi ◽  
Peter J. Didier ◽  
...  
Keyword(s):  
Drug Treatment ◽  
Reverse Transcriptase ◽  
Simian Immunodeficiency Virus ◽  
Mononuclear Cells ◽  
Clinical Signs ◽  
Long Term Treatment ◽  
Essential Components ◽  
Immunodeficiency Virus

ABSTRACTNucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) are essential components in first-line therapy for human immunodeficiency virus (HIV) infection. However, long-term treatment with existing NRTIs can be associated with significant toxic side effects and the emergence of drug-resistant strains. The identification of new NRTIs for the continued management of HIV-infected people therefore is paramount. In this report, we describe the response of a primary isolate of simian immunodeficiency virus (SIV) to 4′-ethynyl-2-fluoro-2′-deoxyadenosine (EFdA) bothin vitroandin vivo. EFdA was 3 orders of magnitude better than tenofovir (TFV), zidovudine (AZT), and emtricitabine (FTC) in blocking replication of SIV in monkey peripheral blood mononuclear cells (PBMCs)in vitro, and in a preliminary study using two SIV-infected macaques with advanced AIDS, it was highly effective at treating SIV infection and AIDS symptomsin vivo. Both animals had 3- to 4-log decreases in plasma virus burden within 1 week of EFdA therapy (0.4 mg/kg of body weight, delivered subcutaneously twice a day) that eventually became undetectable. Clinical signs of disease (diarrhea, weight loss, and poor activity) also resolved within the first month of treatment. No detectable clinical or pathological signs of drug toxicity were observed within 6 months of continuous therapy. Virus suppression was sustained until drug treatment was discontinued, at which time virus levels rebounded. Although the rebound virus contained the M184V/I mutation in the viral reverse transcriptase, EFdA was fully effective in maintaining suppression of mutant virus throughout the drug treatment period. These results suggest that expanded studies with EFdA are warranted.

scholarly journals Construction and In Vitro Characterization of Attenuated Feline Immunodeficiency Virus Long Terminal Repeat Mutant Viruses

2001 ◽  
Vol 75 (2) ◽  
pp. 1054-1060 ◽  
Author(s):  
Luisa Bigornia ◽  
Kristen M. Lockridge ◽  
Ellen E. Sparger
Keyword(s):  
Long Terminal Repeat ◽  
Virus Replication ◽  
Feline Immunodeficiency Virus ◽  
Terminal Repeat ◽  
Immunodeficiency Virus ◽  
Activation Pathways ◽  
Virus Expression ◽  
Transcriptional Elements

ABSTRACT AP-1- and ATF-binding sites are cis-acting transcriptional elements within the U3 domain of the feline immunodeficiency virus (FIV) long terminal repeat (LTR) that serve as targets for cellular activation pathways and may regulate virus replication. We report that FIV LTR mutant proviruses encoding U3 deletions of the ATF-binding sequence exhibited restricted virus expression and replication in both feline lymphocytes and macrophages. In contrast, deletion of the AP-1 site had negligible effects on virus expression and replication. FIV LTR mutant proviruses encoding deletions of both the AP-1 and ATF sites or a 72-bp deletion encompassing the AP-1 site, duplicated C/EBP sites, and ATF sites were severely restricted for virus expression. These results demonstrate that deletion of either the ATF-binding site or multiplecis-acting transcriptional elements attenuates FIV. These attenuated FIV mutants provide opportunities to characterize the role of cis-acting elements in virus replication in vivo and to test LTR mutants as attenuated virus vaccines.

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