Isolation of Lautropia mirabilis from oral cavities of human immunodeficiency virus-infected children.

Lautropia mirabilis, a pleomorphic, motile, gram-negative coccus, has been isolated from the oral cavities of 32 of 60 (53.3%) children infected with human immunodeficiency virus (HIV) and 3 of 25 (12.0%) HIV-uninfected controls; the association of L. mirabilis isolation with HIV infection is significant (P < 0.001). All children in the study, both HIV-infected children and controls, were born to HIV-infected mothers. The presence of this bacterium was not associated with clinical disease in these children. The HIV-infected children with L. mirabilis did not differ from the HIV-infected children without L. mirabilis in immunological status, clinical status, or systemic medications. The role of HIV infection itself or concomitant factors in the establishment of L. mirabilis in the oral cavity remains to be elucidated.

Hepatitis C and human immunodeficiency virus infections in injecting drug users in drug treatment centers in Vietnam

Background. Injecting drug users (IDUs) are at risk of infection with Hepatitis C Virus (HCV) and Human Immunodeficiency Virus (HIV). Independently, each of these viruses is a serious threat to health, with HIV ravaging the body’s immune system, and HCV causing cirrhosis, liver cancer and liver failure. Co-infection with HIV/HCV weakens the response to antiretroviral therapy in HIV patients. IDUs with HIV/HCV co-infection are at a 20 times higher risk of having liver-related morbidity and mortality than IDUs with HIV alone. In Vietnam, studies to ascertain the prevalence of HIV have found high rates, but little is known about their HCV status. ^ Purpose. To measure the prevalence of HCV and HIV infection and identify factors associated with these viruses among IDUs at drug treatment centers in northern Vietnam. ^ Methods. A cross-sectional study was conducted from November 2007 to February 2008 with 455 injecting drug users aged 18 to 39 years, admitted no more than two months earlier to one of four treatment centers in Northern Vietnam (Hatay Province) (response rate=95%). Participants, all of whom had completed detoxification and provided informed consent, completed a risk assessment questionnaire and had their blood drawn to test for the presence of antibody-HCV and antibody-HIV with enzyme immuno assays. Univariate and multivariable logistic regression models were utilized to explore the strength of association using HIV, HCV infections and HIV/HCV co-infection as outcomes and demographic characteristics, drug use and sexual behaviors as factors associated with these outcomes. Unadjusted and adjusted odds ratios and 95% confidence intervals were calculated. ^ Results. Among all IDU study participants, the prevalence of HCV alone was 76.9%, HIV alone was 19.8%. The prevalence of HIV/HCV co-infection was 92.2% of HIV-positive and 23.7% of HCV-positive respondents. No sexual risk behaviors for lifetime, six months or 30 days prior to admission were significantly associated with HCV or HIV infection among these IDUs. Only duration of injection drug use was independently associated with HCV and HIV infection, respectively. Longer duration was associated with higher prevalence. Nevertheless, while HCV infection among IDUs who reported being in their first year of injecting drugs were lower than longer time injectors, their rates were still substantial, 67.5%. ^ Compared with either HCV mono-infection or HIV/HCV non-infection, HIV/HCV co-infection was associated with the length of drug injection history but was not associated with sexual behaviors. Higher education was associated with a lower prevalence of HIV/HCV co-infection. When compared with HIV/HCV non-infection, current marriage was associated with a lower prevalence of HIV/HCV co-infection. ^ Conclusions. HCV was prevalent among IDUs from 18 to 39 years old at four drug treatment centers in northern Vietnam. Co-infection with HCV was predominant among HIV-positive IDUs. HCV and HIV co-infection were closely associated with the length of injection drug history. Further research regarding HCV/HIV co-infection should include non-injecting drug users to assess the magnitude of sexual risk behaviors on HIV and HCV infection. (At these treatment centers non-IDUs constituted 10-20% of the population.) High prevalence of HCV prevalence among IDUs, especially among HIV-infected IDUs, suggests that drug treatment centers serving IDUs should include not only HIV prevention education but they should also include the prevention of viral hepatitis. In addition, IDUs who are HIV-positive need to be tested for HCV to receive the best course of therapy and achieve the best response to HIV treatment. These data also suggest that because many IDUs get infected with HCV in the first year of their injection drug career, and because they also engaged in high risk sexual behaviors, outreach programs should focus on harm reduction, safer drug use and sexual practices to prevent infection among drug users who have not yet begun injecting drugs and to prevent further spread of HCV, HIV and co-infection. ^

A New Multidisciplinary Home Care Telemedicine System to Monitor Stable Chronic Human Immunodeficiency Virus-Infected Patients: A Randomized Study

BACKGROUND: Antiretroviral therapy has changed the natural history of human immunodeficiency virus (HIV) infection in developed countries, where it has become a chronic disease. This clinical scenario requires a new approach to simplify follow-up appointments and facilitate access to healthcare professionals. METHODOLOGY: We developed a new internet-based home care model covering the entire management of chronic HIV-infected patients. This was called Virtual Hospital. We report the results of a prospective randomised study performed over two years, comparing standard care received by HIV-infected patients with Virtual Hospital care. HIV-infected patients with access to a computer and broadband were randomised to be monitored either through Virtual Hospital (Arm I) or through standard care at the day hospital (Arm II). After one year of follow up, patients switched their care to the other arm. Virtual Hospital offered four main services: Virtual Consultations, Telepharmacy, Virtual Library and Virtual Community. A technical and clinical evaluation of Virtual Hospital was carried out. FINDINGS: Of the 83 randomised patients, 42 were monitored during the first year through Virtual Hospital (Arm I) and 41 through standard care (Arm II). Baseline characteristics of patients were similar in the two arms. The level of technical satisfaction with the virtual system was high: 85% of patients considered that Virtual Hospital improved their access to clinical data and they felt comfortable with the videoconference system. Neither clinical parameters [level of CD4+ T lymphocytes, proportion of patients with an undetectable level of viral load (p = 0.21) and compliance levels >90% (p = 0.58)] nor the evaluation of quality of life or psychological questionnaires changed significantly between the two types of care. CONCLUSIONS: Virtual Hospital is a feasible and safe tool for the multidisciplinary home care of chronic HIV patients. Telemedicine should be considered as an appropriate support service for the management of chronic HIV infection. TRIAL REGISTRATION: Clinical-Trials.gov: NCT01117675.

Emergence of a highly pathogenic simian/human immunodeficiency virus in a rhesus macaque treated with anti-CD8 mAb during a primary infection with a nonpathogenic virus

Although simian/human immunodeficiency virus (SHIV) strain DH12 replicates to high titers and causes immunodeficiency in pig-tailed macaques, virus loads measured in SHIVDH12-infected rhesus monkeys are consistently 100-fold lower and none of 22 inoculated animals have developed disease. We previously reported that the administration of anti-human CD8 mAb to rhesus macaques at the time of primary SHIVDH12 infection resulted in marked elevations of virus loads. One of the treated animals experienced rapid and profound depletions of circulating CD4+ T lymphocytes. Although the CD4+ T cell number partially recovered, this monkey subsequently suffered significant weight loss and was euthanized. A tissue culture virus stock derived from this animal, designated SHIVDH12R, induced marked and rapid CD4+ cell loss after i.v. inoculation of rhesus monkeys. Retrospective analyses of clinical specimens, collected during the emergence of SHIVDH12R indicated: (i) the input cloned SHIV remained the predominant virus during the first 5–7 months of infection; (ii) variants bearing only a few of the SHIVDH12R consensus changes first appeared 7 months after the administration of anti-CD8 mAb; (iii) high titers of neutralizing antibody directed against the input SHIV were detected by week 10 and persisted throughout the infection; and (iv) no neutralizing antibody against SHIVDH12R ever developed.

Human Immunodeficiency Virus Reverse Transcriptase and Protease Sequence Database: an expanded data model integrating natural language text and sequence analysis programs

The HIV Reverse Transcriptase and Protease Sequence Database is an on-line relational database that catalogs evolutionary and drug-related sequence variation in the human immunodeficiency virus (HIV) reverse transcriptase (RT) and protease enzymes, the molecular targets of anti-HIV therapy (http://hivdb.stanford.edu). The database contains a compilation of nearly all published HIV RT and protease sequences, including submissions from International Collaboration databases and sequences published in journal articles. Sequences are linked to data about the source of the sequence sample and the antiretroviral drug treatment history of the individual from whom the isolate was obtained. During the past year 3500 sequences have been added and the data model has been expanded to include drug susceptibility data on sequenced isolates. Database content has also been integrated with didactic text and the output of two sequence analysis programs.

Trans-activation by human immunodeficiency virus Tat protein requires the C-terminal domain of RNA polymerase II.

Human immunodeficiency virus (HIV)-encoded trans-activator (Tat) acts through the trans-activation response element RNA stem-loop to increase greatly the processivity of RNA polymerase II. Without Tat, transcription originating from the HIV promoter is attenuated. In this study, we demonstrate that transcriptional activation by Tat in vivo and in vitro requires the C-terminal domain (CTD) of RNA polymerase II. In contrast, the CTD is not required for basal transcription and for the formation of short, attenuated transcripts. Thus, trans-activation by Tat resembles enhancer-dependent activation of transcription. These results suggest that effects of Tat on the processivity of RNA polymerase II require proteins that are associated with the CTD and may result in the phosphorylation of the CTD.

Identification of a hexapeptide inhibitor of the human immunodeficiency virus integrase protein by using a combinatorial chemical library.

Integration of human immunodeficiency virus (HIV) DNA into the human genome requires the virus-encoded integrase (IN) protein, and therefore the IN protein is a suitable target for antiviral strategies. To find a potent HIV IN inhibitor, we screened a "synthetic peptide combinatorial library." We identified a hexapeptide with the sequence HCKFWW that inhibits IN-mediated 3'-processing and integration with an IC50 of 2 microM. The peptide is active on IN proteins from other retroviruses such as HIV-2, feline immunodeficiency virus, and Moloney murine leukemia virus, supporting the notion that a conserved region of IN is targeted. The hexapeptide was also tested in the disintegration reaction. This phosphoryl-transfer reaction can be carried out by the catalytic core of IN alone, and the peptide HCKFWW was found to inhibit this reaction, suggesting that the hexapeptide acts at or near the catalytic site of IN. Identification of an IN hexapeptide inhibitor provides proof of concept for the approach, and, moreover, this peptide may be useful for structure-function analysis of IN.

Interleukin 2 induces CD8+ T cell-mediated suppression of human immunodeficiency virus replication in CD4+ T cells and this effect overrides its ability to stimulate virus expression.

The nonlytic suppression of human immunodeficiency virus (HIV) production from infected CD4+ T cells by CD8+ lymphocytes from HIV-infected individuals is one of the most potent host-mediated antiviral activities observed in vitro. We demonstrate that the pleiotropic cytokine interleukin 2 (IL-2), but not IL-12, is a potent inducer of the CD8+ HIV suppressor phenomenon. IL-2 induces HIV expression in peripheral blood or lymph node mononuclear cells from HIV-infected individuals in the absence of CD8+ T cells. However, IL-2 induces CD8+ T cells to suppress HIV expression when added back to these cultures, and this effect dramatically supersedes the ability to IL-2 to induce HIV expression. Five to 25 times fewer CD8+ cells were required to obtain comparable levels of inhibition of viral production if they were activated in the presence of IL-2 as compared with IL-12 or no exogenous cytokine. Furthermore, IL-2 appeared either to induce a qualitative increase in HIV suppressor cell activity or to increase the relative frequency of suppressor cells in the activated (CD25+) CD8+ populations. Analyses of proviral levels in peripheral blood mononuclear cells suggest that CD8+ T cell-mediated lysis of in vivo infected cells is not induced by IL-2. These results have implications for our understanding of the effects of impaired IL-2 production during HIV disease as well as the overall effects of IL-2-based immunotherapy on HIV replication in vivo.

CD4+ blood lymphocytes are rapidly killed in vitro by contact with autologous human immunodeficiency virus-infected cells.

We have investigated the ability of human immunodeficiency virus (HIV)-infected cells to kill uninfected CD4+ lymphocytes. Infected peripheral blood mononuclear cells were cocultured with autologous 51Cr-labeled uninfected cells. Rapid death of the normal CD4-expressing target population was observed following a brief incubation. Death of blood CD4+ lymphocytes occurred before syncytium formation could be detected or productive viral infection established in the normal target cells. Cytolysis could not be induced by free virus, was dependent on gp120-CD4 binding, and occurred in resting, as well as activated, lymphocytes. CD8+ cells were not involved in this phenomenon, since HIV-infected CEMT4 cells (CD4+, CD8- cells) mediated the cytolysis of uninfected targets. Reciprocal isotope-labeling experiments demonstrated that infected CEMT4 cells did not die in parallel with their targets. The uninfected target cells manifested DNA fragmentation, followed by the release of the 51Cr label. Thus, in HIV patients, infected lymphocytes may cause the depletion of the much larger population of uninfected CD4+ cells without actually infecting them, by triggering an apoptotic death.

Oligomerization of CD4 is required for stable binding to class II major histocompatibility complex proteins but not for interaction with human immunodeficiency virus gp120.

Previous studies have failed to detect an interaction between monomeric soluble CD4 (sCD4) and class II major histocompatibility complex (MHC) proteins, suggesting that oligomerization of CD4 on the cell surface may be required to form a stable class II MHC binding site. To test this possibility, we transfected the F43I CD4 mutant, which is incapable of binding to class II MHC or human immunodeficiency virus (HIV) gp120, into COS-7 cells together with wild-type CD4 (wtCD4). Expression of F43I results in a dominant negative effect: no class II MHC binding is observed even though wtCD4 expression is preserved. Apparently, F43I associates with wtCD4 oligomers and interferes with the formation of functional class II MHC binding structures. In contrast, F43I does not affect the binding of gp120 to wtCD4, implying that gp120 binds to a CD4 monomer. By production and characterization of chimeric CD4 molecules, we show that domains 3 and/or 4 appear to be involved in oligomerization. Several models of the CD4-class II MHC interaction are offered, including the possibility that one or two CD4 molecules initially interact with class II MHC dimers and further associate to create larger complexes important for facilitating T-cell receptor crosslinking.

CT-2576, an inhibitor of phospholipid signaling, suppresses constitutive and induced expression of human immunodeficiency virus.

Viruses such as human immunodeficiency virus (HIV) require cellular activation for expression. Cellular activation in lymphoid cells is associated with augmented accumulation of certain phosphatidic acid (PA) species derived from the hydrolysis of glycan phosphatidylinositol (GPI). This suggests that activation of a phospholipid pathway may play a role in initiation of viral replication. To test this hypothesis, we examined the effect of tat gene expression on the production of cellular PA species, as the Tat protein is essential for HIV expression and has been implicated in activating the expression of multiple host cellular genes. Expression of tat increased the expression of PA. We then tested whether synthetic inhibitors of PA metabolism would inhibit activation of the HIV long terminal repeat by Tat and tumor necrosis factor alpha (TNF-alpha). CT-2576 suppressed both PA generation induced by Tat and HIV long terminal repeat-directed gene expression in response to Tat or TNF-alpha at a posttranscriptional step. CT-2576 also inhibited constitutive as well as TNF-alpha- and interleukin 6-induced expression of HIV p24 antigen in chronically infected U1 cells and in peripheral blood lymphocytes acutely infected with a clinical isolate of HIV. Pharmacological inhibition of synthesis of selected PA species may therefore provide a therapeutic approach to suppression of HIV replication.

Surfactant protein a promotes attachment of Mycobacterium tuberculosis to alveolar macrophages during infection with human immunodeficiency virus.

The incidence of tuberculosis is increasing on a global scale, in part due to its strong association with human immunodeficiency virus (HIV) infection. Attachment of Mycobacterium tuberculosis to its host cell, the alveolar macrophage (AM), is an important early step in the pathogenesis of infection. Bronchoalveolar lavage of HIV-infected individuals demonstrated the presence of a factor which significantly enhances the attachment of tubercle bacilli to AMs 3-fold relative to a normal control population. This factor is surfactant protein A (SP-A). SP-A levels are increased in the lungs of HIV-infected individuals. SP-A levels and attachment of M. tuberculosis to AMs inversely correlate with peripheral blood CD4 lymphocyte counts. Elevated concentrations of SP-A during the progression of HIV infection may represent an important nonimmune risk factor for acquiring tuberculosis, even before significant depletion of CD4 lymphocytes in the peripheral blood occurs.

Inhibitory effect of 9-(2-phosphonylmethoxyethyl)adenine on visna virus infection in lambs: a model for in vivo testing of candidate anti-human immunodeficiency virus drugs.

The acyclic nucleoside phosphonate analog 9-(2-phosphonylmethoxyethyl)adenine (PMEA) was recently found to be effective as an inhibitor of visna virus replication and cytopathic effect in sheep choroid plexus cultures. To study whether PMEA also affects visna virus infection in sheep, two groups of four lambs each were inoculated intracerebrally with 10(6.3) TCID50 of visna virus strain KV1772 and treated subcutaneously three times a week with PMEA at 10 and 25 mg/kg, respectively. The treatment was begun on the day of virus inoculation and continued for 6 weeks. A group of four lambs were infected in the same way but were not treated. The lambs were bled weekly or biweekly and the leukocytes were tested for virus. At 7 weeks after infection, the animals were sacrificed, and cerebrospinal fluid (CSF) and samples of tissue from various areas of the brain and from lungs, spleen, and lymph nodes were collected for isolation of virus and for histopathologic examination. The PMEA treatment had a striking effect on visna virus infection, which was similar for both doses of the drug. Thus, the frequency of virus isolations was much lower in PMEA-treated than in untreated lambs. The difference was particularly pronounced in the blood, CSF, and brain tissue. Furthermore, CSF cell counts were much lower and inflammatory lesions in the brain were much less severe in the treated lambs than in the untreated controls. The results indicate that PMEA inhibits the propagation and spread of visna virus in infected lambs and prevents brain lesions, at least during early infection. The drug caused no noticeable side effects during the 6 weeks of treatment.

Protein structure-based design of potent orally bioavailable, nonpeptide inhibitors of human immunodeficiency virus protease.

A class of potent nonpeptidic inhibitors of human immunodeficiency virus protease has been designed by using the three-dimensional structure of the enzyme as a guide. By employing iterative protein cocrystal structure analysis, design, and synthesis the binding affinity of the lead compound was incrementally improved by over four orders of magnitude. An inversion in inhibitor binding mode was observed crystallographically, providing information critical for subsequent design and highlighting the utility of structural feedback in inhibitor optimization. These inhibitors are selective for the viral protease enzyme, possess good antiviral activity, and are orally available in three species.