Human AIDS Research Articles

Replication potentials of HIV-1/HSIV in PBMCs from northern pig-tailed macaque (Macaca leonina).

The northern pig-tailed macaque (Macaca leonina) has been identified as an independent species of Old World monkey, and we previously found that PBMCs from M. leonina were susceptible to human immunodeficiency virus type 1 (HIV-1), which may be due to the absence of a TRIM5 protein restricting HIV-1 replication. Here we investigated the infection potentials of six laboratory adapted HIV-1 strains and three primary HIV-1 isolates in PBMCs from M. leonina. The results indicate that these strains are characterized by various but low replication levels, and among which, HIV-1NL4-3 shows the highest replication ability. Based on the abundant evidence of species-specific interactions between restriction factors APOBEC3 and HIV/SIV-derived Vif protein, we subsequently examined the replication potentials of vif-substituted HIV-1 (HSIV) in M. leonina PBMCs. Notably, HSIV-vifmac and stHIV-1SV chimeras, two HIV-1NL4-3-derived viruses encoding the viral infectivity factor (Vif) protein from SIVmac239, replicated robustly in cells from M. leonina, which suggests that HSIV could effectively antagonize the antiviral activity of APOBEC3 proteins expressed in cells of M. leonina. Therefore, our data demonstrate that M. leonina has the potential to be developed into a promising animal model for human AIDS.

Association of the HLA-B*52 allele with non-progression to AIDS in Brazilian HIV-1-infected individuals

Several human leukocyte antigen (HLA) class I alleles are associated with the susceptibility to human immunodeficiency virus-1 (HIV-1) infection and/or AIDS progression. Of these, the HLA-B alleles are considered the strongest genetic determinant of disease outcome. We evaluated the influence of the HLA-B alleles on AIDS progression among HIV-1-positive individuals from Rio de Janeiro, Brazil, who were categorized as rapid progressors (RPs), typical progressors (TPs) or long-term non-progressors (LTNPs). In this study, significant differences in HLA-B allele frequencies were observed among the three progression groups for the B*48, B*49 and B*52 alleles. After controlling for other factors associated with AIDS progression, the presence of the B*52 allele was shown to be a significant protective factor (hazard ratio (HR) 0.49 (95% confidence interval (CI) 0.27-0.90) P<0.03). Although no direct association was observed between the presence of the B*27 or B*57 allele and the LTNP profile compared with the TP or RP groups, the adjusted model confirmed that these alleles are protective factors against AIDS progression (HR 0.62 (95% CI 0.38-0.99) P<0.05), as previously described. These data corroborate the existence of significant differences in HLA-B allele frequencies among the distinct AIDS progression profiles and further elucidate the role of HLA alleles in the outcome of HIV infections in diverse populations.

Assessing the Impact of Climate Change and Land Use Variation on Microbial Transport Using Watershed Scale-modeling

Uncertainty surrounding microbial fate and transport renders the assessment of climate change effects on waterborne pathogens complex and difficult to forecast. The objective of this study is to use watershed modeling to predict the impacts of future climate change and land management scenarios on microbial water quality. Preliminary findings suggest an increased risk to human health due to direct consequences of climate change. Results of watershed-scale microbial load modeling can inform the adoption of pollution control measures required to protect human health and aid development of new water policy.

A Peer Education Program: Delivering Highly Reliable Sexual Health Promotion Messages in Schools

PurposeThis article describes preliminary findings from an implementation study of a school-based peer education program on sexual health for high-school youth. The responses of youth participants are described. MethodsQualitative data were collected across one semester in two successive waves of participants (N = 4 schools), including observations of program activities, in-depth interviews of stakeholders, focus groups with youth participants (N = 62 peer educators and 60 ninth graders), and brief surveys of youth participants (N = 678). Grounded theory methodology informed data collection and analysis. ResultsTeen Prevention Education Program (Teen PEP) was adapted and replicated with fidelity to the model in North Carolina high schools. All program “inputs” and five core model components (outputs) were implemented. The principal accommodation made was to implement the entire curriculum within one half of a school year rather than across the entire school year although still using the same amount of instructional time. Youth participants attributed high value to the experience, noting that the sexual health information they received was both new and important for their lives and that they felt they learned it better from their peers than from instruction in traditional health class. The majority of participants reported that the program helped them across a range of areas related to both social well-being and sexual health. ConclusionsTeen PEP developers have been able to successfully adapt and replicate it in North Carolina, in settings that need sexual health education services for youth both because of the paucity of existing services in many areas and because of the evidence of risk in the form of high rates of pregnancy and sexually transmitted infections, including human immunodeficiency virus or AIDS in youth 15–19 years of age. Youth reported benefits across a range of social and sexual health-related areas.

Effect of Bac-D™ on Hatchability, Conductance, Growth Rate and Feed Conversion on Turkey Poults

The major factor facing the commercial poultry industry today is the cost of feed. Breeding companies have put great emphasis on selecting their lines for rapid growth and low feed to gain to increase the efficiency of production. Even though genetics have made drastic differences in growth parameters, evident from the last 45 years of genetic selection, producers still employ other methods to help birds perform more efficiently including; feed additives, temperature control, incubation, ventilation, hatchery sanitation and egg disinfection. Bac-DTM is a novel disinfectant, which is currently being used as a wound wash for humans and animals. The product utilizes benzalkonium chloride, a well-studied quaternary ammonium compound, which has been generally regarded as safe (GRAS). Bac-DTM has been effectively used as a human first aid antiseptic for many years. The objectives of this trial were to determine the effects of Bac-DTM on egg conductance, hatchability, body weight and feed conversion (FC) in turkey eggs and poults. Turkey eggs were washed with Bac-DTM then incubated under standard conditions while recording egg conductance and hatchability. Body weights were measured at hatch, 21d and 42d. The results showed that egg conductance, hatchability, or body weights of chicks hatched from Bac-DTM washed eggs did not differ significantly from water washed controls. However, mean feed conversion was significantly lower (p<0.0062) in Bac-DTM poults (FCR = 1.10) compared with the control birds (FCR = 1.17) at 21d. The improvement in FCR may be due to reduced levels of slightly pathogenic bacteria in the gut resulting from the Bac-DTM egg sanitization. The potential reduction in FCR will be of significant economic impact to poultry producers.

Speech Analysis Based On Image Information from Lip Movement

Deaf and hard of hearing people often have problems being able to understand and lip read other people. Usually deaf and hard of hearing people feel left out of conversation and sometimes they are actually ignored by other people. There are a variety of ways hearing-impaired person can communicate and gain accsss to the information. Communication support includes both technical and human aids. Human aids include interpreters, lip-readers and note-takers. Interpreters translate the Sign Language and must therefore be qualified. In this paper, vision system is used to track movements of the lip. In the experiment, the proposed system succesfully can differentiate 11 type of phonemes and then classified it to the respective viseme group. By using the proposed system the hearing-impaired persons could practise pronaunciations by themselve without support from the instructor.

Cisplatin resistance by induction of aldo-keto reductase family 1 member C2 in human bladder cancer cells

Cisplatin is currently the most effective anti-tumor agent available against bladder cancer. To clarify the mechanism underlying cisplatin resistance in bladder cancer, the present study examined the role of the aldo-keto reductase family 1 member C2 (AKR1C2) protein on chemoresistance using a human bladder cancer cell line. The function of AKR1C2 in chemoresistance was studied using the human HT1376 bladder cancer cell line and the cisplatin-resistant HT1376-CisR subline. AKR1C2 was expressed in HT1376-CisR cells, but not in the parental cells. The effect of small interfering (si) RNAs and an inhibitor targeting AKR1C2 was examined to determine whether cisplatin sensitivity can be rescued by blocking AKR1C2 expression or function. Silencing of AKR1C2 mRNA or inhibition of AKR1C2 by 5β-cholanic acid resulted in a decrease in the survival of cells following cisplatin exposure. Intracellular accumulation of reactive oxygen species (ROS) was determined using a 2,7-dichlorodihydrofluorescein diacetate (H2DCFDA) fluorescent probe. Cisplatin exposure increased the level of intracellular ROS in HT1376 cells in a dose-dependent manner. The ROS levels in HT1376-CisR cells were significantly lower than those in HT1376 cells and knockdown of AKR1C2 mRNA significantly restored ROS levels. Cisplatin exposure did not increase intracellular ROS in HT1376-CisR cells, although the level of intracellular ROS increased in HT1376 cells following cisplatin exposure. Silencing of AKR1C2 mRNA restored the ROS increase response to cisplatin and menadione as an oxidative stressor in HT1376-CisR cells. Menadione has the function of an oxidative stressor. The silencing of AKR1C2 mRNA restored the increased ROS response to cisplatin and menadione in HT1376-CisR cells. These results indicate that induction of AKR1C2 in human bladder cancer cells aids in the development of cisplatin resistance through antioxidative effects. The results of this study indicate that AKR1C2 may be an effective molecular target for restoring cisplatin resistance.

MicroRNA‐494 within an oncogenic microRNA megacluster regulates G 1 /S transition in liver tumorigenesis through suppression of mutated in colorectal cancer

Hepatocellular carcinoma (HCC) is associated with poor survival for patients and few effective treatment options, raising the need for novel therapeutic strategies. MicroRNAs (miRNAs) play important roles in tumor development and show deregulated patterns of expression in HCC. Because of the liver’s unique affinity for small nucleic acids, miRNA-based therapy has been proposed in the treatment of liver disease. Thus, there is an urgent need to identify and characterize aberrantly expressed miRNAs in HCC. In our study, we profiled miRNA expression changes in de novo liver tumors driven by MYC and/or RAS, two canonical oncogenes activated in a majority of human HCCs. We identified an up-regulated miRNA megacluster comprised of 53 miRNAs on mouse chromosome 12qF1 (human homolog 14q32). This miRNA megacluster is up-regulated in all three transgenic liver models and in a subset of human HCCs. An unbiased functional analysis of all miRNAs within this cluster was performed. We found that miR-494 is overexpressed in human HCC and aids in transformation by regulating the G1/S cell cycle transition through targeting of the Mutated in Colorectal Cancer tumor suppressor. miR-494 inhibition in human HCC cell lines decreases cellular transformation, and anti-miR-494 treatment of primary MYC-driven liver tumor formation significantly diminishes tumor size. Conclusion: Our findings identify a new therapeutic target (miR-494) for the treatment of HCC. (Hepatology 2014;58:202–215)

Bio-insect and artificial robot interaction: learning mechanism and experiment

This paper addresses fuzzy-logic-based reinforcement learning architecture and experimental results for the interaction between an artificial robot and a living bio-insect. The main goal of this research is to drag the bio-insect towards the desired goal area without any human aid. To achieve the goal, we seek to design robot intelligence architecture such that the robot can drag the bio-insect using its own learning mechanism. The main difficulties of this research are to find an interaction mechanism between the robot and bio-insect and to design a robot intelligence architecture. In simple interaction experiment, the bio-insect does not react to stimuli such as light, vibration, or artificial robot motion. From various trials-and-error efforts, we empirically found an actuation mechanism for the interaction between the robot and bio-insect. Nevertheless, it is difficult to control the movement of the bio-insect due to its uncertain and complex behavior. For the artificial robot, we design a fuzzy-logic-based reinforcement learning architecture that helps the artificial robot learn how to control the movement of the bio-insect under uncertain and complex behavior. Here, we present the experimental results regarding the interaction between an artificial robot and a bio-insect.

R-Loop Mediated Transcription-Associated Recombination in trf4Δ Mutants Reveals New Links between RNA Surveillance and Genome Integrity

To get further insight into the factors involved in the maintenance of genome integrity we performed a screening of Saccharomyces cerevisiae deletion strains inducing hyperrecombination. We have identified trf4, a gene encoding a non-canonical polyA-polymerase involved in RNA surveillance, as a factor that prevents recombination between DNA repeats. We show that trf4Δ confers a transcription-associated recombination phenotype that is mediated by the nascent mRNA. In addition, trf4Δ also leads to an increase in the mutation frequency. Both genetic instability phenotypes can be suppressed by overexpression of RNase H and are exacerbated by overexpression of the human cytidine deaminase AID. These results suggest that in the absence of Trf4 R-loops accumulate co-transcriptionally increasing the recombination and mutation frequencies. Altogether our data indicate that Trf4 is necessary for both mRNA surveillance and maintenance of genome integrity, serving as a link between RNA and DNA metabolism in S. cerevisiae.

Deregulations in the Cyclin-Dependent Kinase-9-Related Pathway in Cancer: Implications for Drug Discovery and Development

The CDK9-related pathway is an important regulator of mammalian cell biology and is also involved in the replication cycle of several viruses, including the human immunodeficiency virus type 1. CDK9 is present in two isoforms termed CDK9-42 and CDK9-55 that bind noncovalently type T cyclins and cyclin K. This association forms a heterodimer, where CDK9 carries the enzymatic site and the cyclin partner functions as a regulatory subunit. This heterodimer is the main component of the positive transcription elongation factor b, which stabilizes RNA elongation via phosphorylation of the RNA pol II carboxyl terminal domain. Abnormal activities in the CDK9-related pathway were observed in human malignancies and cardiac hypertrophies. Thus, the elucidation of the CDK9 pathway deregulations may provide useful insights into the pathogenesis and progression of human malignancies, cardiac hypertrophy, AIDS and other viral-related maladies. These studies may lead to the improvement of kinase inhibitors for the treatment of the previously mentioned pathological conditions. This review describes the CDK9-related pathway deregulations in malignancies and the development of kinase inhibitors in cancer therapy, which can be classified into three categories: antagonists that block the ATP binding site of the catalytic domain, allosteric inhibitors, and small molecules that disrupt protein-protein interactions.

The Turkish Strategic Restrictions towards the Arab Revolts (2011 – 2012)

Turkey is distinguished with property of elements of enough power, which makes it a regional power: the location, the area, the population, and the strong economy. The creed, identity, skills and natural resources, all these factors assist Turkey to prove its domination and power in a rising shape, but its strategic concept did not appear before the present Turkish government comes in 2002 and may be, because of the dispersion of power elements in the state. The Turkish policies at that stage could be described in confronting internal, regional and international issues. It is a policy of running the variety, or (management of diversity) and from the other side, (policy of crises management). Turkey witnesses ever since discussions about the significance of the concealed true power of Turkey in the field of its international relations, and to which extent it invests them in its diplomatic relations. These discussions amount between two trends; one attempts to found legitimacy of the concept of Turkey to remain mortgaged to the connected policies with centers of powers formed outside. That is by showing Turkey’s level of concealed power less than level, which it should be on, through frozen operations of evaluation connected with stage situations. The second is a trend presenting excessive optimistic estimations, mortgaging that Turkey can explode its power strictly, without new analysis and dynamic to the elements of the changing and static power which Turkey owns in the shadow of the new international situation. Ankara sticked to neutrality at the beginning of the Arab incidents towards the Tunisian Revolt in December 2010. But with the hasting of incidents in Egypt after one month from that date Ardoghan initiated by calling former president Husni Mobarak to withdraw, and Abdullah Ghoul was the first president to visit Egypt after the collapse of Mobarak, the thing that duplicated the popularity that Turkey obtains on the Egyptian sphere, and it is what was reflected in receiving Ardoghan at his visit to Egypt in September, 2011. He paid a visit heading a big delegation of businessmen. This assured Turkey's desire to enlarge its economic relation with the biggest Arab state. At the start of the Libyan Revolt in February 2011, Turkey hesitated to act. Turkey had big investments with Al-Quaddafi's regime. Therefore, it assured this significance to reach a political settlement of the Libyan crisis, at the beginning of incidents, fore-warning from seriousness of fighting like that which happened in Iraq before, the thing that harmed Turkey's picture inside Libya. But after passing the resolution of the Security Council 1973, which allowed forcing an area of air-navigation prohibition over Libya, Ankara's stand was changed by sending sea-forces to participate in the NATO operations there, beside the participation in the human aid efforts. Also, the break- out of Bahrain Revolt in February 2011 placed Turkey among numerous accounts. Turkey had large economic interests with states of the Gulf Cooperative Council, and had to respect the security specialty of Gulf region, and it did not wish to encourage Iran to interfere in the Gulf affairs. Though, Ankara wanted to rise its diplomatic role in an attempt to quiet the Shia't –Sunni tensions in the region, that harm its special interests. Ankara presented mediation.

MAKNA IDEOLOGI DAN BENTUK PROPAGANDA MEDIA ( Studi Semiotika Barthes media Eramuslim dan National Israel Terhadap Kasus Mavi Marmara )

After many years, relationship between Turk and Israel are close. But the relation changed to bad after Turk decided to given human aid ship to Palestine. The human aid ship under arrested by Israel before docked. The raid Israel made several crew human aid died. The moment of the raid Israel known as Mavi Marmara cases. The war of propaganda between Turk against Israel have been made. One of their purpose is to created good opinion public for their activity. Eramuslim is one of all media Indonesia which is vocal to against the raid for mavi marmara. While National Israel is one of the media Israel which is consist to made news about mavi marmara. Beside the News, there some ideology hiding both of news from Eramuslim and National Israel. The Ideology become identity for news Eramuslim and National Israel,

Accessory Genes Confer a High Replication Rate to Virulent Feline Immunodeficiency Virus

Feline immunodeficiency virus (FIV) is a lentivirus that causes AIDS in domestic cats, similar to human immunodeficiency virus (HIV)/AIDS in humans. The FIV accessory protein Vif abrogates the inhibition of infection by cat APOBEC3 restriction factors. FIV also encodes a multifunctional OrfA accessory protein that has characteristics similar to HIV Tat, Vpu, Vpr, and Nef. To examine the role of vif and orfA accessory genes in FIV replication and pathogenicity, we generated chimeras between two FIV molecular clones with divergent disease potentials: a highly pathogenic isolate that replicates rapidly in vitro and is associated with significant immunopathology in vivo, FIV-C36 (referred to here as high-virulence FIV [HV-FIV]), and a less-pathogenic strain, FIV-PPR (referred to here as low-virulence FIV [LV-FIV]). Using PCR-driven overlap extension, we produced viruses in which vif, orfA, or both genes from virulent HV-FIV replaced equivalent genes in LV-FIV. The generation of these chimeras is more straightforward in FIV than in primate lentiviruses, since FIV accessory gene open reading frames have very little overlap with other genes. All three chimeric viruses exhibited increased replication kinetics in vitro compared to the replication kinetics of LV-FIV. Chimeras containing HV-Vif or Vif/OrfA had replication rates equivalent to those of the virulent HV-FIV parental virus. Furthermore, small interfering RNA knockdown of feline APOBEC3 genes resulted in equalization of replication rates between LV-FIV and LV-FIV encoding HV-FIV Vif. These findings demonstrate that Vif-APOBEC interactions play a key role in controlling the replication and pathogenicity of this immunodeficiency-inducing virus in its native host species and that accessory genes act as mediators of lentiviral strain-specific virulence.

Immunocompromised Status in Patients With Necrotizing Soft-Tissue Infection

There is a scarcity of research on immunocompromised patients with necrotizing soft-tissue infection (NSTI). To evaluate the effect of immunocompromised status in patients with NSTI. Single-institution retrospective cohort study at a tertiary academic teaching hospital affiliated with a major cancer center. Patients with NSTI. Treatment at Brigham and Women's Hospital and Dana-Farber Cancer Institute between November 25, 1995, and April 25, 2011. Necrotizing soft-tissue infection-associated in-hospital mortality. Two hundred one patients were diagnosed as having NSTI. Forty-six were immunocompromised (as defined by corticosteroid use, active malignancy, receipt of chemotherapy or radiation therapy, diagnosis of human immunodeficiency virus or AIDS, or prior solid organ or bone marrow transplantation with receipt of chronic immunosuppression). At presentation, immunocompromised patients had lower systolic blood pressure (105 vs 112 mm Hg, P = .02), glucose level (124 vs 134 mg/dL, P = .03), and white blood cell count (6600/μL vs 17 200/μL, P < .001) compared with immunocompetent patients. Immunocompromised patients were less likely to have been transferred from another institution (26.1% vs 52.9%, P = .001), admitted to a surgical service (45.7% vs 83.2%, P < .001), or undergone surgical debridement on admission (4.3% vs 61.3%, P = .001). Time to diagnosis and time to first surgical procedure were delayed in immunocompromised patients (P < .001 and P = .001, respectively). Immunocompromised patients had higher NSTI-associated in-hospital mortality (39.1% vs 19.4%, P = .01). AND RELEVANCE Immunocompromised status in patients with NSTI in this study is associated with delays in diagnosis and surgical treatment and with higher NSTI-associated in-hospital mortality. At presentation, immunocompromised patients may fail to exhibit typical clinical and laboratory signs of NSTI. Physicians caring for similar patient populations should maintain a heightened level of suspicion for NSTI and consider early surgical evaluation and treatment.

Evaluating early differences in regulatory T cell levels in the MAIDS model of AIDS. (P6187)

Abstract Murine acquired immunodeficiency syndrome (MAIDS), caused by the murine leukemia virus (MuLV), serves as an animal model to study human AIDS. Infection with the LP-BM5 isolate of MuLV leads to progressive immunodeficiency in MAIDS-susceptible C57BL/6 mice, while resistant BALB/c mice are able to mount a direct and controlled immune response to eradicate the virus. Experiments measuring the protein expression of two natural immunosuppressive molecules, indoleamine 2, 3-dioxygenease (IDO) and interleukin-10 (IL-10), showed significant strain specific differences during the first two weeks after infection, as measured by ELISA. Since IDO and IL-10 expression can be either directly or indirectly upregulated by regulatory T (Tregs) cells, we then compared levels of Treg populations between the two strains in both lymph node and spleen using FACS. Our preliminary findings suggest that BALB/c mice may have a higher percentage of regulatory T cells in both lymph node and spleen as compared to their MAIDS-susceptible counterparts.

Latino Parents' Plans to Communicate About Sexuality With their Children

This study investigated 86 Latino parents' intentions to communicate about sexuality issues with their children. They reported on their history of sexuality education, when they would first discuss sexuality-related topics, and their perceived effectiveness of each topic. Compared with a sample of Caucasian parents, Latino parents intended to discuss sexual abuse/molestation at an earlier age, but planned to discuss human reproduction, intercourse, and AIDS at significantly later ages. Suggestions for assisting Latino parents with communications regarding sexuality topics are provided.

Lessons on Non-Progression of HIV Disease from Monkeys

Rhesus macaques infected with simian immunodeficiency virus (SIV) represent the most widely used model for studies related to understanding infection, pathology, immunology, and intervention strategies for HIV infection and AIDS in humans. This model recapitulates the significant impact of host immunogenetics and inter-individual variations on the natural disease course of HIV-AIDS in humans. In addition to the parallel kinetics for fast- and slow-progressing disease course observed in majority of animals, a small subset of animals exhibit long-term non-progression (LTNP) or elite control (EC) status defined as low to undetectable viral loads in the absence of any interventions for prolonged periods. Therefore, the rhesus macaque model has been and continues to be the most extensively adopted experimental system for studies to not only confirm observations from HIV-ADIS in humans but also to validate several mechanistic features of the infection and disease course, which otherwise would be impractical and immoral to be performed in humans.

An In vitro Model for the Study of HIV Infection of Thymocytes

The study of human thymocytes requires an appropriate matrix to enable the proper function of thymocytes. Although OP9-DL1 cells have been well established as an ideal co-culture system for the generation of T-cells from their progenitors; their ability to support a mixed population of mature human thymocytes for in vitro HIV infection studies has yet to be established. We assessed the effects of co-culturing a heterogeneous population of mature human thymocytes with a mouse derived cell line (OP9) transduced with the notch ligand delta like 1 (OP9-DL-1) and compared this to standard co-culture with human thymic epithelial cells (TEC). Co-culturing thymocytes with OP9- DL1 cells resulted in higher viability and lower apoptosis when compared to TEC co-cultures. The subset distribution and CD127 expression of thymocytes varied slightly between conditions. Thymocytes co-cultured with OP9-DL1 cells had a lower proportion of CD3+DP cells and higher proportion of SP4 cells compared to TEC co-cultures. The mature CD3+CD4+CD8- (SP4) cells also had lower levels of CD127 expression in OP9-DL1 cultures when compared to TEC. Interleukin-7 stimulation of thymocytes resulted in a decrease in CD127 expression in OP9-DL1 co-cultures, as previously observed with TEC co-cultures. Thymocytes co-cultured with OP9-DL1 tended to have higher levels of IL-7 induced STAT-5 phosphorylation and had higher levels of Interleukin-7 induced Bcl-2 expression. OP9-DL1 cells provide a microenvironment which is permissive to HIV infection in thymocytes in vitro. Co-culturing thymocytes with OP9-DL1 will facilitate the study of human thymocytes and aid in the study of exogenous stimuli or infection on individual thymocyte subsets.

Growth potentials of CCR5-tropic/CXCR4-tropic HIV-1mt clones in macaque cells

Growth potentials of CCR5-tropic/CXCR4-tropic HIV-1mt clones in macaque cells