indinavir-sulfate and Disease-Models--Animal

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

HIV-associated sensory neuropathy (HIV-SN) is the most frequent manifestation of HIV disease. It often presents with significant neuropathic pain and is associated with previous exposure to neurotoxic nucleoside reverse transcriptase inhibitors. However, HIV-SN prevalence remains high even in resource-rich settings where these drugs are no longer used. Previous evidence suggests that exposure to indinavir, a protease inhibitor commonly used in antiretroviral therapy, may link to elevated HIV-SN risk. Here, we investigated whether indinavir treatment was associated with the development of a "dying back" axonal neuropathy and changes in pain-relevant limb withdrawal and thigmotactic behaviours. After 2 intravenous injections of indinavir (50 mg/kg, 4 days apart), adult rats developed hind paw mechanical hypersensitivity, which peaked around 2 weeks post first injection (44% reduction from baseline). At this time, animals also had (1) significantly changed thigmotactic behaviour (62% reduction in central zone entries) comparing with the controls and (2) a significant reduction (45%) in hind paw intraepidermal nerve fibre density. Treatment with gabapentin, but not amitriptyline, was associated with a complete attenuation of hind paw mechanical hypersensitivity observed with indinavir treatment. Furthermore, we found a small but significant increase in microglia with the effector morphology in the lumbar spinal dorsal horn in indinavir-treated animals, coupled with significantly increased expression of phospho-p38 in microglia. In summary, we have reported neuropathic pain-related sensory and behavioural changes accompanied by a significant loss of hind paw skin sensory innervation in a rat model of indinavir-induced peripheral neuropathy that is suitable for further pathophysiological investigation and preclinical evaluation of novel analgesics.

Topics: Amines; Analgesics; Animals; Calcitonin Gene-Related Peptide; Calcium-Binding Proteins; Cyclohexanecarboxylic Acids; Disease Models, Animal; Exploratory Behavior; Gabapentin; gamma-Aminobutyric Acid; Ganglia, Spinal; Gene Expression Regulation; Glial Fibrillary Acidic Protein; HIV Infections; HIV Protease Inhibitors; Hyperalgesia; Indinavir; Male; Metacarpus; Microfilament Proteins; Microglia; Neuralgia; Pain Measurement; Pain Threshold; Physical Stimulation; Rats; Rats, Wistar; Spinal Cord; Statistics, Nonparametric

Diminished insulin sensitivity is a characteristic feature of various pathological conditions such as hypertension and activation of peroxisome proliferator activated receptor α (PPARα) has been shown to enhance insulin resistance and reduce capacity for glucose uptake in muscles. The present study was designed to evaluate the interactions of PPARα and GLUT4 in a model of hypertensive renal injury by studying deoxycorticosterone acetate (DOCA)-salt induced hypertension in wild-type (WT) and PPARα knockout (KO) mice. PPARα WT and KO mice were uninephrectomized (UNx) and implanted subcutaneously DOCA and drank 1% sodium chloride/1% potassium chloride with or without a GLUT4 antagonist, indinavir (20 mg/kg/day, s.c) or PPARα ligand, fenofibrate (100 mg/kg/day, orally). DOCA/salt treatment increased urinary sodium excretion and urine volume (p<0.05) in PPARα KO mice compared to WT littermates. Indinavir increased proteinuria (p<0.01) in DOCA/salt-treated PPARα KO mice compared to WT littermates but did not affect heart and kidney weight index in DOCA/salt KO or WT-treated mice. Urinary sodium excretion (UNaV) and urine volume (UV) were increased by indinavir (p<0.01) and fenofibrate (p<0.05) in DOCA/salt-treated PPARα KO mice compared to WT mice. Urinary nitric oxide was greater in both fenofibrate (p<0.05) and indinavir-treated WT mice (p<0.05) compared to KO mice. These data suggest that in hypertensive nephropathy, GLUT4 probably exerts a renoprotective role that was enhanced with the activation of PPARα receptors by a mechanism that may be related to increased nitric oxide production.

Topics: Animals; Desoxycorticosterone Acetate; Disease Models, Animal; Fenofibrate; Glucose Transporter Type 4; Indinavir; Kidney; Kidney Diseases; Male; Mice, Knockout; Nephrectomy; Nitric Oxide; Potassium Chloride; PPAR alpha; Sodium; Sodium Chloride; Time Factors; Urination

The present study evaluated the efficacy of garlic plant and Indinavir on cryptosporidiosis in experimentally immunosuppressed infected rats. One hundred forty five Wister rats aging 3 weeks were divided into five groups: GI: normal control, GII: Indinavir treated control, GIII: immunosuppressed infected, GIV: immunosuppressed infected and treated with garlic and GV: immunosuppressed infected and treated with Indinavir. All were subjected to clinical, parasitological and histopathological examination at different days post infection (P.I.). The results showed that in GIII, all rats had diarrhea, loss of appetite, weakness and limited movement, with 51.4% death rate. In both treated groups, some rats regained activities, with death rate of 33.3% (GV) and non GIV. There was significant decrease in the number of excreted oocysts at 5th and 10th day post treatment (P.T.) in treated groups. One week P.T., in GIV, the number of excreted oocysts had continued in decreasing while in GV, it was insignificantly increased. No cure rate was detected in both treated groups as oocysts still excreted till the end of experiment. The histopathological changes improved in treated groups in spite of the presence of some parasites on the epithelial surfaces of ileum.

Topics: Animals; Antiprotozoal Agents; Cryptosporidiosis; Cyclophosphamide; Disease Models, Animal; Garlic; Immunosuppression Therapy; Immunosuppressive Agents; Indinavir; Male; Phytotherapy; Plant Extracts; Rats; Rats, Wistar

To evaluate the efficacy of postexposure prophylaxis with a combination of zidovudine (ZDV), lamivudine (3TC) and indinavir (IDV), after vaginal exposure to HIV.. : Experimental intravaginal exposure of female cynomolgus macaques to SIVmac251.. ZDV/3TC/IDV treatment was initiated 4 h after exposure and continued for 28 days. Groups of six animals received a placebo or a combination of oral ZDV (4.5 mg/kg), 3TC (2.5 mg/kg) and IDV (20 mg/kg) twice daily or subcutaneous ZDV (4.5 mg/kg) and 3TC (2.5 mg/kg) twice daily, and a higher dose of IDV (60 mg/kg) administered orally twice daily.. In the placebo group, all animals were infected. Antiretroviral association protected one of the six animals if all drugs were administered orally and four of the six animals if ZDV and 3TC were administered subcutaneously and IDV was given orally at triple dose. In infected animals, viremia was significantly delayed and lowered in treated animals than in animals given placebo, and high CD4 cell counts were maintained in the treated animals, at least in the medium term. Antiretroviral dosages made in macaques receiving the same treatments showed that protection efficacy could be linked to antiretroviral plasmatic concentration.. This study shows, for the first time in macaques, that the postexposure prophylaxis recommended for humans may be effective after vaginal exposure. Improvements in pharmacokinetic parameters significantly increased treatment efficiency.

Topics: Administration, Oral; Animals; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; CD4 Lymphocyte Count; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Indinavir; Injections, Subcutaneous; Lamivudine; Macaca fascicularis; Sexually Transmitted Diseases, Viral; Simian Acquired Immunodeficiency Syndrome; Vagina; Viral Load; Viremia; Zidovudine

A growing body of evidence suggests HIV patients are at a greater risk for developing atherosclerosis. However, clinical investigations have generated conflicting results with regard to whether antiretrovirals are independently involved in the development of HIV-associated atherosclerosis. By administering antiretrovirals in an atherogenic mouse model, we determined whether two commonly prescribed antiretrovirals, the protease inhibitor indinavir and the nucleoside reverse transcriptase inhibitor AZT, can induce premature atherosclerosis. C57BL/6 mice were administered an atherogenic diet+/-AZT, indinavir, or AZT plus indinavir for 20 weeks. Aortic intima-media thickness (IMT) and cross-sectional area (CSA) were determined. Compared to controls, treatment with AZT, indinavir or AZT plus indinavir, significantly increased aortic IMT and CSA. This suggests that antiretrovirals can directly exacerbate atherogenesis, in the absence of interaction with a retroviral infection. To elucidate the role of oxidant injury in the drug-induced initiation of atherosclerosis, a separate group of mice were treated for 2 weeks with an atherogenic diet+/-AZT, indinavir or AZT plus indinavir. Aortic reactive oxygen species (ROS) production and glutathione/glutathione disulfide (GSH/GSSG) ratios, as well as plasma levels of 8-isoprostanes (8-iso-PGF(2alpha)) and lipids were determined. At 2 weeks, aortic ROS was increased and GSH/GSSG ratios were decreased in all antiretroviral treatment groups. Plasma 8-iso-PGF(2alpha) was increased in the AZT and AZT plus indinavir-treated groups. At 20 weeks, increased ROS production was maintained for the AZT and indinavir treatment groups, and increased 8-iso-PGF(2alpha) levels remained elevated in the AZT treatment group. Cholesterol levels were moderately elevated in the AZT and AZT plus indinavir-treated groups at 2 but not 20 weeks. Conversely, indinavir treatment increased plasma cholesterol at 20 but not 2 weeks. Thus, though effects on plasma lipid levels occurred, with effects of the individual antiretrovirals variable across the treatment period, there was consistent evidence of oxidant injury across both early and late time points. Together with the known metabolic abnormalities induced by antiretrovirals, drug-induced oxidant production may contribute to the development of antiretroviral-associated atherosclerosis.

Topics: Animals; Anti-HIV Agents; Atherosclerosis; Cholesterol; Disease Models, Animal; Glutathione; Glutathione Disulfide; Indinavir; Isoprostanes; Male; Mice; Mice, Inbred C57BL; Reactive Oxygen Species; Triglycerides; Tunica Intima; Zidovudine

Antiretroviral therapy (ART) shows variable blood-brain barrier penetration. This may affect the development of neurological complications of HIV infection. In attempts to attenuate viral growth for the nervous system, cell-based nanoformulations were developed with the focus on improving drug pharmacokinetics. We reasoned that ART carriage could be facilitated within blood-borne macrophages traveling across the blood-brain barrier. To test this idea, an HIV-1 encephalitis (HIVE) rodent model was used where HIV-1-infected human monocyte-derived macrophages were stereotactically injected into the subcortex of severe combined immunodeficient mice. ART was prepared using indinavir (IDV) nanoparticles (NP, nanoART) loaded into murine bone marrow macrophages (BMM, IDV-NP-BMM) after ex vivo cultivation. IDV-NP-BMM was administered i.v. to mice resulting in continuous IDV release for 14 days. Rhodamine-labeled IDV-NP was readily observed in areas of HIVE and specifically in brain subregions with active astrogliosis, microgliosis, and neuronal loss. IDV-NP-BMM treatment led to robust IDV levels and reduced HIV-1 replication in HIVE brain regions. We conclude that nanoART targeting to diseased brain through macrophage carriage is possible and can be considered in developmental therapeutics for HIV-associated neurological disease.

Topics: Animals; Biological Availability; Bone Marrow Cells; Brain; Cell Movement; Cells, Cultured; Disease Models, Animal; Drug Administration Schedule; Encephalitis, Viral; HIV-1; Humans; Indinavir; Macrophages; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Mice, SCID; Nanocapsules; Severe Combined Immunodeficiency; Virus Replication

Population studies indicate that moderate hyperbilirubinemia is associated with reduced incidence of cardiovascular diseases, including hypertension. Despite this correlative evidence, no studies have directly tested the hypothesis that moderate increases in plasma bilirubin levels can attenuate the development of hypertension. This hypothesis was tested by treating mice with Indinavir, a drug that competes with bilirubin for metabolism by UDP-glucuronosyltransferase 1A1 (UGT1A1). Treatment of mice with Indinavir (500 mg x kg(-1) x day(-1), gavage) resulted in a twofold increase in plasma unconjugated bilirubin levels. Next, we determined the effect of Indinavir-induced changes in plasma bilirubin on the development of ANG II-dependent hypertension. Moderate hyperbilirubinemia was induced 3 days before the implantation of an osmotic minipump that delivered ANG II at a rate of 1 microg x kg(-1) x min(-1). ANG II infusion increased mean arterial pressure (MAP) by 20 mmHg in control mice but by only 6 mmHg in mice treated with Indinavir (n = 6). Similar to Indinavir treatment, direct infusion of bilirubin (37.2 mg x kg(-1) x day(-1) i.v.) resulted in a twofold increase in plasma bilirubin levels and also attenuated the development of ANG II-dependent hypertension. Moderate hyperbilirubinemia resulted in an increase in plasma nitrate/nitrite levels, which averaged 36 +/- 2 vs. 50 +/- 7 microM in ANG II vehicle vs. Indinavir-treated mice (n = 5). Moderate hyperbilirubinemia resulted in attenuation of vascular oxidative stress as determined by dihydroethidium staining of aortic segments. These results indicate that moderate hyperbilirubinemia prevents ANG II-dependent hypertension by a mechanism that may involve decreases in vascular oxidative stress.

Topics: Angiotensin II; Animals; Bilirubin; Blood Pressure; Cardiomegaly; Disease Models, Animal; Glucuronosyltransferase; Hyperbilirubinemia; Hypertension; Indinavir; Male; Mice; Mice, Inbred C57BL; Nitrates; Nitrites; Organic Cation Transport Proteins; Oxidative Stress

In HIV-infected persons on highly active antiretroviral therapy, residual virus is found in lymphoid tissues. Indinavir concentrations in lymph node mononuclear cells of patients on highly active antiretroviral therapy were approximately 25% to 35% of those in blood mononuclear cells, suggesting that drug insufficiency contributes to residual virus in lymphoid tissues. Therefore, we developed novel lipid-indinavir nanoparticles targeted to lymphoid tissues. Given subcutaneously, these nanoparticles provided indinavir concentrations 250% to 2270% higher than plasma indinavir concentrations in both peripheral and visceral lymph nodes. Improved indinavir delivery was reflected in reduced viral RNA and CD4(+) T-cell rebound. This study optimized lipid nanoparticle formulation with respect to indinavir in lymphoid tissues of HIV-infected macaques. Regardless of lipid characteristic tested (charge, fluidity, and steric modification), indinavir binds completely to lipid at pH 7.4 but is reversed at pH 5.5 or lower. Compared with previous formulations, nanoparticles composed of disteroyl phosphatidylcholine and methyl polyethylene glycol-disteroyl phosphatidylethanolamine (DSPC:mPEG-DSPE) provided 6-fold higher indinavir levels in lymph nodes and enhanced drug exposure in blood. Enhanced anti-HIV activity paralleled improved intracellular drug accumulation. Collectively, these data suggest that indinavir nanoparticles composed of DSPC:mPEG-DSPE provided the most effective lymphoid delivery and could maximally suppress the virus in lymphoid tissues.

Topics: Animals; Anti-HIV Agents; CD4 Lymphocyte Count; Cell Line; Disease Models, Animal; Drug Carriers; HIV Infections; HIV-2; Hydrogen-Ion Concentration; Indinavir; Injections, Subcutaneous; Lipids; Lymph Nodes; Lymphoid Tissue; Macaca nemestrina; Nanostructures; Phosphatidylcholines; RNA, Viral; Tissue Distribution

Complex dosing regimens, costs, side effects, biodistribution limitations, and variable drug pharmacokinetic patterns have affected the long-term efficacy of antiretroviral medicines. To address these problems, a nanoparticle indinavir (NP-IDV) formulation packaged into carrier bone marrow-derived macrophages (BMMs) was developed. Drug distribution and disease outcomes were assessed in immune-competent and human immunodeficiency virus type 1 (HIV-1)-infected humanized immune-deficient mice, respectively. In the former, NP-IDV formulation contained within BMMs was adoptively transferred. After a single administration, single-photon emission computed tomography, histology, and reverse-phase-high-performance liquid chromatography (RP-HPLC) demonstrated robust lung, liver, and spleen BMMs and drug distribution. Tissue and sera IDV levels were greater than or equal to 50 microM for 2 weeks. NP-IDV-BMMs administered to HIV-1-challenged humanized mice revealed reduced numbers of virus-infected cells in plasma, lymph nodes, spleen, liver, and lung, as well as, CD4(+) T-cell protection. We conclude that a single dose of NP-IDV, using BMMs as a carrier, is effective and warrants consideration for human testing.

Topics: Animals; Chemistry, Pharmaceutical; Disease Models, Animal; Drug Delivery Systems; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Macrophages; Male; Mice; Mice, Inbred BALB C; Mice, Inbred NOD; Mice, SCID; Microscopy, Electron, Scanning; Nanostructures; Nanotechnology; Tissue Distribution

The ability of highly active antiretroviral therapy (HAART) to prevent the onset of HIV-associated dementia and to prevent or reduce the neuropathological features of HIV encephalitis (HIVE) remains unclear. Using a severe combined immunodeficient (SCID) mouse model of HIVE, we determined the effects of regular HAART treatment on HIVE. Before studying HAART in infected SCID mice, nonmanipulated SCID mice were treated with a single injection of the HAART cocktail (consisting of zidovudine, lamivudine, and indinavir) to determine optimum dosage and sampling time and to measure antiretroviral levels in the brain. After these preliminary studies, SCID mice that were inoculated with either HIV-infected or uninfected human monocytes were given intraperitoneal (IP) injections of HAART three times daily over a 1- and 2-week period. All three drugs were detected in the brain using a novel drug extraction technique and a modified high-performance liquid chromatography method. HAART significantly decreased the amount of astrogliosis and viral load in treated mice compared with mice that received vehicle injections. These studies offer insight into the ability of HAART to treat HIV infection of the brain.

Topics: AIDS Dementia Complex; Animals; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Brain; Disease Models, Animal; Drug Therapy, Combination; HIV Protease Inhibitors; Humans; Indinavir; Lamivudine; Male; Mice; Mice, SCID; Monocytes; Viral Load; Zidovudine

Vgamma2Vdelta2+ T cells play a role in antimicrobial responses. It is unknown whether adaptive Vgamma2Vdelta2+ T cell responses during active mycobacterial coinfection of human immunodeficiency virus-infected humans can be generated during effective antiretroviral treatment. Here, simian immunodeficiency virus (SIV)mac-infected macaques previously exposed to bacille Calmette-Guerin (BCG) were reinfected with BCG, were treated either with tenofovir or tenofovir plus indinavir, and were assessed for the development of Vgamma2Vdelta2+ T cell responses during active BCG coinfection. A restored capacity of Vgamma2Vdelta2+ T cells to undergo major expansions and pulmonary migration during active BCG coinfection was detected after simultaneous BCG reinfection and treatment with tenofovir of the SIVmac-infected macaques. Interestingly, a restored expansion of Vgamma2Vdelta2+ T cells in the SIVmac/BCG-coinfected macaques was detectable, even though antiretroviral treatment was initiated 1 month after BCG reinfection. Importantly, the restored expansion of Vgamma2Vdelta2+ T cells coincided with increases in numbers of purified protein derivative-specific interferon- gamma -producing CD4+ T cells and increases in the magnitude of their proliferative responses. In contrast, the SIVmac-infected control macaques exhibited diminished responses of Vgamma2Vdelta2+ T cells and mycobacterium-specific CD4+ T cells during active BCG coinfection. Our results suggest that the development of adaptive immune responses of phosphoantigen-specific Vgamma2Vdelta2+ T cells during active mycobacterium/HIV coinfection requires control of viral infection and immune competence of peptide-specific CD4+ T cells.

Topics: Adenine; Amino Acid Sequence; Animals; Cattle; CD4-Positive T-Lymphocytes; Disease Models, Animal; Drug Therapy, Combination; HIV Protease Inhibitors; Indinavir; Lung; Lymphocyte Count; Macaca mulatta; Macaca nemestrina; Molecular Sequence Data; Mycobacterium bovis; Organophosphonates; Receptors, Antigen, T-Cell, gamma-delta; Reverse Transcriptase Inhibitors; Simian Acquired Immunodeficiency Syndrome; Simian Immunodeficiency Virus; Tenofovir; Tuberculosis, Bovine

Treatment with HIV-1 protease inhibitors (PI) is associated with a reduced incidence or regression of Kaposi sarcoma (KS). Here we show that systemic administration of the PIs indinavir or saquinavir to nude mice blocks the development and induces regression of angioproliferative KS-like lesions promoted by primary human KS cells, basic fibroblast growth factor (bFGF), or bFGF and vascular endothelial growth factor (VEGF) combined. These PIs also block bFGF or VEGF-induced angiogenesis in the chorioallantoic membrane assay with a potency similar to paclitaxel (Taxol). These effects are mediated by the inhibition of endothelial- and KS-cell invasion and of matrix metalloproteinase-2 proteolytic activation by PIs at concentrations present in plasma of treated individuals. As PIs also inhibit the in vivo growth and invasion of an angiogenic tumor-cell line, these data indicate that PIs are potent anti-angiogenic and anti-tumor molecules that might be used in treating non-HIV KS and in other HIV-associated tumors.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Disease Models, Animal; Endothelial Growth Factors; Endothelium, Vascular; Extraembryonic Membranes; Female; Fibroblast Growth Factor 2; HIV Protease Inhibitors; Humans; Indinavir; Lymphokines; Matrix Metalloproteinase 2; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Neovascularization, Pathologic; Paclitaxel; Saquinavir; Sarcoma, Kaposi; Skin; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Human immunodeficiency virus (HIV) protease inhibitors (PIs) recently have been reported to be active against Pneumocystis carinii in cell culture. Twelve anti-HIV drugs were analyzed for their effects against rat P. carinii by an ATP cytotoxicity assay. Indinavir and saquinavir exhibited slight anti-P. carinii activity at concentrations above those that can be clinically achieved in serum; other PIs and nucleoside and nonnucleoside reverse-transcriptase inhibitors were inactive against the organism. Anti-HIV drugs, alone or in combination, did not materially reduce the organism count in the treatment of P. carinii pneumonia in immunosuppressed mice. Thus, anti-HIV drugs have little or no activity against P. carinii in these in vitro and in vivo systems. Caution should be used when interpreting reports of the susceptibility of P. carinii to anti-HIV drugs on the basis of in vitro testing only.

Topics: Administration, Oral; Animals; Anti-HIV Agents; Disease Models, Animal; Drug Therapy, Combination; HIV Protease Inhibitors; Indinavir; Lung; Mice; Mice, Inbred C3H; Pneumocystis; Pneumocystis Infections; Saquinavir

We have utilized combination antiretroviral therapy following human immunodeficiency virus type 1-induced human CD4(+) thymocyte depletion in the SCID-hu mouse to examine the immune competence of reconstituting thymocytes which appear following administration of combination therapy. These cells express a normal distribution of T-cell receptor variable gene families and are responsive to costimulatory signals. These results suggest that normal thymic function may be restored following antiretroviral treatment.

Topics: Animals; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Didanosine; Disease Models, Animal; Drug Therapy, Combination; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Mice; Mice, SCID; Receptors, Antigen, T-Cell, alpha-beta; Reverse Transcriptase Inhibitors; Thymus Gland; Zidovudine

Human immunodeficiency virus type 1 (HIV-1)-infected SCID-hu thymic implants depleted of CD4(+) cells can support renewed thymopoiesis derived from both endogenous and exogenous T-cell progenitors after combination antiretroviral therapy. However, successful production of new thymocytes occurs transiently. Possible explanations for the temporary nature of this thymic reconstitution include cessation of the thymic stromal support function, exhaustion of T-cell progenitors, and viral resurgence. Distinguishing between these processes is important for the development of therapeutic strategies aimed at reconstituting the CD4(+) T-cell compartment in HIV-1 infection. Using an HIV-1 strain engineered to express the murine HSA heat-stable antigen surface marker, we explored the relationship between HIV-1 expression and CD4(+) cell resurgence kinetics in HIV-1-depleted SCID-hu implants following drug therapy. Antiviral therapy significantly suppressed HIV-1 expression in double-positive (DP) CD4/CD8 thymocytes, and the eventual secondary decline of DP thymocytes following therapy was associated with renewed viral expression in this cell subset. Thymocytes derived from exogenous T-cell progenitors induced to differentiate in HIV-1-depleted, drug-treated thymic implants also became infected. These results indicate that in this model, suppression of viral replication occurs transiently and that, in spite of drug therapy, virus resurgence contributes to the transient nature of the renewed thymic function.

Topics: Animals; Anti-HIV Agents; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Didanosine; Disease Models, Animal; Drug Therapy, Combination; Hematopoietic Stem Cell Transplantation; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Kinetics; Lymphocyte Depletion; Mice; Mice, SCID; Reverse Transcriptase Inhibitors; Thymus Gland; Zidovudine