The large intestine as a major reservoir for simian immunodeficiency virus in macaques with long-term, nonprogressing infection

Although patients with human immunodeficiency virus type 1 infection who are receiving antiretroviral therapy and those with long-term, nonprogressive infection (LTNPs) usually have undetectable viremia, virus persists in tissue reservoirs throughout infection. However, the distribution and magnitude of viral persistence and replication in tissues has not been adequately examined. Here, we used the simian immunodeficiency virus (SIV) macaque model to quantify and compare viral RNA and DNA in the small (jejunum) and large (colon) intestine of LTNPs. In LTNPs with chronic infection, the colon had consistently higher viral levels than did the jejunum. The colon also had higher percentages of viral target cells (memory CD4(+) CCR5(+) T cells) and proliferating memory CD4(+) T cells than did the jejunum, whereas markers of cell activation were comparable in both compartments. These data indicate that the large intestine is a major viral reservoir in LTNPs, which may be the result of persistent, latently infected cells and higher turnover of naive and central memory CD4(+) T cells in this major immunologic compartment.     

Isolation and characterization of a new chimpanzee lentivirus (simian immunodeficiency virus isolate cpz-ant) from a wild-captured chimpanzee.

OBJECTIVE: To assess the prevalence of infection with simian immunodeficiency virus (SIV) isolate cpz, a lentivirus closely related to HIV-1, in chimpanzees, and to obtain new SIVcpz isolates. METHODS: Forty-four wild-captured chimpanzees in Belgium and C?te d'Ivoire were tested for HIV and SIV antibodies. Virus was isolated from the peripheral blood lymphocytes of positive animals and characterized by electron microscopy, Western blot and radioimmunoprecipitation assay. RESULTS: One animal had antibodies that cross-reacted with HIV-1. A lentivirus was isolated and referred to as SIVcpz-ant. With regard to molecular weight patterns, SIVcpz-ant differs from SIVcpz-gab' an HIV-1-related virus isolated from a wild-captured chimpanzee in Gabon. The major core protein, the transmembrane and outer membrane glycoproteins of the SIVcpz-ant strain consistently had higher molecular weights. Significantly more HIV-1-positive sera reacted with the envelope proteins of the Gabonese SIVcpz-gab strain than with the SIVcpz-ant strain. CONCLUSIONS: This study shows that natural infection of wild-captured chimpanzees with an HIV-related virus may not be uncommon. The diversity of the two chimpanzee isolates, the different geographical origin and the absence of disease suggest that chimpanzees have not recently become SIVcpz-infected.     

Impaired performance on a rhesus monkey neuropsychological testing battery following simian immunodeficiency virus infection

Infection with simian immunodeficiency virus (SIV) in macaques provides an excellent model of AIDS including HIV-induced central nervous system (CNS) pathology and cognitive/behavioral impairment. Recently a behavioral test battery has been developed for macaques based on the CANTAB human neuropsychological testing battery. As with human neuropsychological batteries, different tasks are thought to involve different neural substrates, and therefore performance profiles may assess function in particular brain regions. Ten rhesus monkeys were infected with SIV after being trained on two or more of the battery tasks addressing memory (delayed nonmatching to sample, DNMS), spatial working memory (using a self-ordered spatial search task, SOSS), motivation (progressive-ratio, PR), reaction time (RT), and/or fine motor skills (bimanual motor skill, BMS). Performance was compared to that of 9 uninfected monkeys. Overall, some aspect of performance was impaired in all 10 monkeys following infection. Consistent with results in human AIDS patients, individual performance was impaired most often on battery tasks thought to be sensitive to frontostriatal dopaminergic functioning such as SOSS, RT, and BMS. These results further demonstrate the similarity of behavioral impairment produced by SIV and HIV on homologous behavioral tests, and establish the utility of the testing battery for further investigations into the CNS mechanisms of the reported behavioral changes.     

Autoimmunity and HIV/simian immunodeficiency virus infection: A two edged sword

The purpose of this review is to provide an overview of the spectrum of autoimmune responses that we have so far characterized in the simian immunodeficiency virus (SIV)-infected disease susceptible rhesus macaques, the potential role of the lymphopenic state for the generation of the autoimmune response and the important new finding that such autoimmune response in fact can serve to provide both clinical benefit and clinical disease depending on the stage of the disease and the nature of the host proteins that are recognized during this process.     

Pathology of dual Mycobacterium leprae and simian immunodeficiency virus infection in rhesus monkeys

Three rhesus monkeys were experimentally inoculated with sooty-mangabey-derived Mycobacterium leprae and were inadvertently infected with the simian immunodeficiency virus (SIV) as well. They died of an immunodeficiency syndrome, and at autopsy all had lesions caused by M. leprae. One monkey was inoculated twice with M. leprae, initially with an inoculum from a sooty mangabey that was not infected with SIV and, subsequently, with an inoculum from a mangabey that was SIV infected. The monkey did not develop clinical lesions and became strongly lepromin skin test (LST) positive after the first inoculation, but became infected with both agents and LST negative following the second inoculation. These observations suggest that SIV-infected rhesus monkeys have an increased susceptibility to M. leprae infection and, by analogy, imply that HIV-infected human beings may have an increased susceptibility as well.     

Pathogenesis of acute infection in rhesus macaques with a lymphocyte-tropic strain of simian immunodeficiency virus.

The simian immunodeficiency virus, SIVmac, causes disease affecting multiple organ systems in macaques similar to human immunodeficiency virus infection in humans. Molecularly cloned SIVmac with a strong lymphocyte tropism was used in pathogenesis experiments to correlate viral cell tropism with disease. In 5 animals, exhaustive analyses on viruses from tissues and identification of infected precursor cells were done at multiple times during infection to ensure the virus had not mutated into a macrophage-tropic variant. Viral replication was measured by infectivity, infectious center assays, and in situ hybridization. Lymphocytes produced most virus in tissues, indicating the virus maintained its cell tropism in vivo. Lymphocytes in bone marrow were latently infected and those in the spleen and lymph nodes were productively infected. The virus failed to replicate in the brain after intracerebral inoculation. SIVmac that maintained a strong tropism for lymphocytes and a corresponding poor tropism for macrophages can cause persistent infection and AIDS but not other diseases such as primary pneumonia and encephalitis in rhesus macaques.     

The molecular epidemiology of varicella-zoster virus: evidence for geographic segregation

Of 75 varicella-zoster virus (VZV) isolates obtained from patients in Africa, Asia, and the Far East, 74 (98.6%) were found to be positive for a BglI restriction site in gene 54. By contrast, <22% of strains from patients in the United Kingdom and in North and South America were positive for the BglI restriction site. Viruses positive for BglI were significantly more common in zoster occurring in patients of nonwhite origin (P<.05). Irrespective of the country in which the sample was obtained, 98% of strains positive for BglI clustered within a single phylogenetic group, which we termed "group A"; the exception was 1 strain that appeared to be recombinant genotype C/A. We used the BglI site to examine both the spread of type A viruses in the United Kingdom and the patterns of VZV infections within persons from different ethnic groups who grew up in the United Kingdom or abroad.     

Rates and impact of hepatitis on human immunodeficiency virus infection in a large African cohort

AIM:To determine the rates and impact of hepatitis B virus(HBV) and hepatitis C virus(HCV) infections on response to long-term highly active antiretroviral therapy(HAART) in a large human immunodeficiency virus(HIV) population in Nigeria.METHODS:HBV and HCV as well as HIV infections are endemic in sub Saharan Africa.This was a retrospective cohort study of 19 408 adults who were recruited between June 2004 and December 2010 in the AIDS Prevention Initiative in Nigeria in Nigeria programme at Jos University Teaching Hospital.Serological assays,including HBV surface antigen(HBsAg) and hepatitis C antibody were used to categorise hepatitis status of the patients.HBsAg was determined using enzyme immunoassay(EIA)(Monolisa HBsAg Ultra3;Bio-Rad).HCV antibody was tested using third generation EIA(DIA.PRO Diagnostic,Bioprobes srl,Milan,Italy).HIV RNA levels were measured using Roche COBAS Amplicor HIV-1 monitor test version 1.5(Roche Diagnostics,GmbH,Mannheim,Germany) with a detection limit of 400 copies/mL.Flow cytometry was used to determine CD4+ cell count(Partec,GmbH Munster,Germany).Comparison of categorical and continuous variables were achieved using Pearson’s χ 2 and Kruskal Wallis tests respectively,on MedCalc for Windows,version 9.5.0.0(MedCalc Software,Mariakerke,Belgium).RESULTS:With an overall hepatitis screening rate of over 90% for each virus;HBV,HCV and HBV/HCV were detected in 3162(17.8%),1983(11.3%) and 453(2.5%) HIV infected adults respectively.The rate of liver disease was low,but highest among HIV monoinfected patients(29,0.11%),followed by HBV coinfected patients(15,0.08%).Patients with HBV coinfection and triple infection had higher log 10 HIV RNA loads(HBV:4.6 copies/mL vs HIV only:4.5 copies/mL,P<0.0001) and more severe immune suppression(HBV:645,55.4%;HBV/HCV:97,56.7%) prior to initiation of HAART compared to HIV mono-infected patients(1852,48.6%)(P<0.0001).Of 3025 patients who were 4.4 years on HAART and whose CD4 cell counts results at baseline and end of follow up were available for     

Effect of mycobacterial infection on virus loads and disease progression in simian immunodeficiency virus-infected rhesus monkeys

The effect of a mycobacterial infection on AIDS disease was studied in the simian model. Monkeys were infected with the primary virulent isolate SIV/DeltaB670 and inoculated 90 days later with BCG, an attenuated strain of Mycobacterium bovis. All monkeys experienced a dramatic transient increase in plasma viremia and CCR5 expression on T lymphocytes after BCG inoculation. Only two of the four SIV+ animals had substantial proliferative responses to PPD, with poor responders developing disseminated BCG during the course of the experiment. BCG inoculation of SIV-infected long-term nonprogressor (LTNP) monkeys was also performed. Similar to the acutely infected animals, two of three LTNPs experienced increases in plasma viral levels and CCR5 expression. In the majority of animals studied, there was no accelerated progression to AIDS despite the concomitant transient stimulation of virus replication and CCR5 expression on T lymphocytes.     

Pattern of SIVagm infection in patas monkeys suggests that host adaptation to simian immunodeficiency virus infection may result in resistance to infection and virus extinction

Patas monkeys were not reported to carry species‐specific simian immunodeficiency virus (SIV), but cross‐species transmission of SIVagm to patas monkeys occurred in the wild. We report that patas monkeys share immunophenotypic features with natural hosts of SIV; that is, low levels of CD4+ T cells and low CCR5 expression on CD4+ T cells. In 1 patas monkey with undetectable levels of CD4+ T cells, experimental exposure to SIVagm did not result in infection. The other experimentally infected patas monkeys showed an infection pattern similar to SIV infection in natural hosts. Thus, down‐regulation of CD4 and CCR5 expression on CD4+ T cells may effectively control human immunodeficiency virus acquisition and result in SIV extinction.     

Full-length genome sequence of a simian immunodeficiency virus from a wild-captured sun-tailed monkey in Gabon provides evidence for a species-specific monophyletic SIVsun lineage

Since the first characterization of SIVsun (L14 strain) from a sun-tailed monkey (Cercopithecus solatus) in Gabon in 1999, no further information exists about the evolutionary history and geographic distribution of this lentivirus. Here, we report the full-length molecular characterization of a second SIVsun virus (SIVsunK08) naturally infecting a wild-caught sun-tailed monkey. The SIVsunK08 strain was most closely related to SIVsunL14 and clustered with members of the SIVmnd-1/SIVlhoest group. SIVsunK08 shared identical functional motifs in the LTR, Gag and Env proteins with SIVsunL14. Our data indicate that C. solatus is naturally infected with a monophyletic SIVsun strain.     

Alterations in the course of experimental syphilis associated with concurrent simian immunodeficiency virus infection.

Case reports suggest that the course of syphilis is altered in patients infected with human immunodeficiency virus (HIV). To investigate this issue, a model of syphilis in rhesus macaques with and without simian immunodeficiency virus (SIV) was developed. After intradermal inoculation with Treponema pallidum, 2 SIV-infected monkeys had persistent ulcerative primary lesions and 1 developed secondary syphilis. Two SIV-uninfected controls developed transient nonulcerative primary lesions. Only the controls showed consistent VDRL antibody responses. In contrast, reciprocal antibody titers to T. pallidum detected by microhemagglutination were higher in SIV-infected animals (greater than or equal to 20,480) than controls (greater than or equal to 1280). All 4 animals developed a full range of T. pallidum antigen-specific antibodies shown by immunoblot and had similar peak lymphocyte proliferative responses to T. pallidum antigens. These results support the contention that retrovirus-induced immunodeficiency delays clearance of T. pallidum from sites of infection and may impair the humoral immune response to syphilis.