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Vaginal inserts that can be used on demand before or after sex may be a desirable human immunodeficiency virus (HIV) prevention option for women. We recently showed that inserts containing tenofovir alafenamide fumarate (TAF, 20 mg) and elvitegravir (EVG, 16 mg) were highly protective against repeated simian/human immunodeficiency virus (SHIV) vaginal exposures when administered to macaques 4 hours before or after virus exposure (93% and 100%, respectively). Here, we show in the same macaque model that insert application 8 hours or 24 hours after exposure maintains high efficacy (94.4% and 77.2%, respectively). These data extend the protective window by TAF/EVG inserts and inform their clinical development for on-demand prophylaxis in women. [ABSTRACT FROM AUTHOR]

Background Event-driven HIV prevention strategies are a priority for users who do not require daily pre-exposure prophylaxis (PrEP). Regimens containing integrase strand transfer inhibitors (INSTIs) are under evaluation as alternatives to daily PrEP. To better understand INSTI distribution and inform dosing selection we compared the pharmacology of two-dose boosted elvitegravir and unboosted bictegravir regimens in MSM. Materials and methods Blood, rectal and penile secretions and rectal biopsies were collected from 63 HIV-negative MSM aged 18–49 years. Specimens were collected up to 96 h after two oral doses of tenofovir alafenamide and emtricitabine with elvitegravir boosted by cobicistat or unboosted bictegravir given 24 h apart. Antiretroviral drugs were measured by LC-MS. Results Mean bictegravir plasma concentrations remained above the 95% protein-adjusted effective concentration 96 h after dosing [273 (95% CI: 164–456) ng/mL] whereas elvitegravir plasma concentrations became undetectable 48 h after the second dose. Bictegravir and elvitegravir reached rectal tissues within 2 h after the first dose, and elvitegravir tissue concentrations [1.07 (0.38–13.51) ng/mg] were greater than bictegravir concentrations [0.27 (0.15–0.70) ng/mg]. Both INSTIs became undetectable in tissues within 96 h. Elvitegravir and bictegravir were not consistently detected in penile secretions. Conclusions Whereas bictegravir plasma concentrations persist at least 4 days after a two-oral-dose HIV prophylaxis regimen, elvitegravir accumulates in mucosal tissues. Differing elvitegravir and bictegravir distribution may result in variable mucosal and systemic antiviral activity and can inform dosing strategies for event-driven HIV prevention. [ABSTRACT FROM AUTHOR]

Genital inflammation (GI) undermines topical human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) efficacy through unknown mechanisms. Here, associations between activated endocervical CD4 + T-cell numbers and higher deoxyadenosine triphosphate (dATP) concentrations suggest that competition for intracellular metabolites within HIV target cells may reduce the efficacy of antiretroviral-based PrEP in women with GI. [ABSTRACT FROM AUTHOR]

Background Transmitted human immunodeficiency virus (HIV) drug resistance can threaten the efficacy of antiretroviral therapy and pre-exposure prophylaxis (PrEP). Drug-resistance testing is recommended at entry to HIV care in the United States and provides valuable insight for clinical decision making and population-level monitoring. Methods We assessed transmitted drug-resistance–associated mutation (TDRM) prevalence and predicted susceptibility to common HIV drugs among US persons with HIV diagnosed during 2014–2018 who had a drug resistance test performed ≤3 months after HIV diagnosis and reported to the National HIV Surveillance System and who resided in 28 jurisdictions where ≥20% of HIV diagnoses had an eligible sequence during this period. Results Of 50 747 persons in the analysis, 9616 (18.9%) had ≥1 TDRM. TDRM prevalence was 0.8% for integrase strand transfer inhibitors (INSTIs), 4.2% for protease inhibitors, 6.9% for nucleoside reverse transcriptase inhibitors (NRTIs), and 12.0% for non-NRTIs. Most individual mutations had a prevalence <1.0% including M184V (0.9%) and K65R (0.1%); K103N was most prevalent (8.6%). TDRM prevalence did not increase or decrease significantly during 2014–2018 overall, for individual drug classes, or for key individual mutations except for M184V (12.9% increase per year; 95% confidence interval, 5.6–20.6%). Conclusions TDRM prevalence overall and for individual drug classes remained stable during 2014–2018; transmitted INSTI resistance was uncommon. Continued population-level monitoring of INSTI and NRTI mutations, especially M184V and K65R, is warranted amidst expanding use of second-generation INSTIs and PrEP. [ABSTRACT FROM AUTHOR]

Objectives: We conducted a detailed pharmacokinetic assessment in macaques treated with vaginal gels formulated with HIV integrase strand transfer inhibitors (INSTIs) to better understand drug distribution and identify INSTI concentrations associated with previously demonstrated in vivo protection against vaginal simian HIV challenge.Methods: Six macaques received vaginal gel containing 1% raltegravir (30 mg) once-weekly over 6 weeks. Following a washout period, five macaques received once-weekly gel containing 0.23% L-870,812 (7 mg). Drug concentrations were measured in plasma, mucosal fluids and vaginal tissues at baseline and 2, 5 and 24 h post-dosing.Results: The median maximum concentration (Cmax) for raltegravir and L-870,812 in plasma was below the limit of quantification and 41.1 ng/mL, respectively. The Cmax in vaginal fluids (1441 and 1250 μg/mL) and tissues (266.7 and 368.4 μg/g) was achieved 2-5 h after dosing, respectively. A similar half-life was observed for raltegravir and L-870,812 in vaginal fluids (8-10 h) and remained 3-4 orders of magnitude above the protein-adjusted IC95 (0.016 and 0.106 μg/mL, respectively) at 24 h. Drug concentrations in vaginal fluids correlated well with those in vaginal tissues (Pearson r ≥ 0.788). Both drugs were consistently detected in rectal fluids 2 h after vaginal dosing, albeit at much lower levels (31-92-fold) than those in vaginal fluids.Conclusions: To the best of our knowledge, this study provides the first data on INSTI levels in vaginal tissues associated with in vivo protection and demonstrates rectal drug distribution of INSTIs after vaginal dosing. These findings may inform dose selection for topical products with INSTIs for HIV prevention. [ABSTRACT FROM AUTHOR]

Background: HIV exposure to penile tissues provides a risk of acquisition among men, yet studies evaluating penile antiretroviral (ARV) drug distribution have been lacking. We measured ARVs on urethral and glans surface swabs collected following a dose of tenofovir alafenamide, emtricitabine, elvitegravir, darunavir and cobicistat.Methods: Thirty-five HIV-negative male participants provided urethral swabs, glans swabs, rectal swabs, blood and urine up to 96 h following a single dose of tenofovir alafenamide/emtricitabine/elvitegravir/cobicistat and darunavir. ARVs were measured by liquid chromatography-mass spectrometry with a lower limit of detection (LOD) of 1 ng/swab for swabs and 10 ng/mL for plasma and urine. Concentrations are reported as median and range.Results: Urethral swab emtricitabine and darunavir concentrations peaked at 4 h for emtricitabine (36 ng/swab; 3-307 ng/swab) and 8 h for darunavir (25 ng/swab; 2-52 ng/swab). Glans swab emtricitabine and darunavir concentrations peaked 24 h after dosing (emtricitabine 14 ng/swab, Conclusions: We document ARV dosing in the urethra and on the glans surface with high drug concentrations noted for emtricitabine and darunavir and lower tenofovir and elvitegravir concentrations. Data suggest a potential protective role of urethral emtricitabine or darunavir against penile HIV acquisition. [ABSTRACT FROM AUTHOR]

We used a novel penile simian-human immunodeficiency virus (SHIV) transmission model to investigate whether long-acting cabotegravir (CAB LA) prevents penile SHIV acquisition in macaques. Twenty-two macaques were exposed to SHIV via the foreskin and urethra once weekly for 12 weeks. Of these, 6 received human-equivalent doses of CAB LA, 6 received oral emtricitabine/tenofovir disoproxil fumarate, and 10 were untreated. The efficacy of CAB LA was high (94.4%; 95% confidence interval, 58.2%-99.3%) and similar to that seen with oral emtricitabine/tenofovir disoproxil fumarate (94.0%; 55.1%-99.2%). The high efficacy of CAB LA in the penile transmission model supports extending the clinical advancement of CAB LA preexposure prophylaxis to heterosexual men. [ABSTRACT FROM AUTHOR]

Background: Tenofovir alafenamide (TAF)-based regimens are being evaluated for pre-exposure prophylaxis (PrEP). We used a macaque model of repeated exposures to simian human immunodeficiency virus (SHIV) to investigate whether TAF alone or the combination of TAF and emtricitabine (FTC) can prevent vaginal infection.Methods: Pigtail macaques were exposed vaginally to SHIV162p3 once a week for up to 15 weeks. Animals received clinical doses of FTC/TAF (n = 6) or TAF (n = 9) orally 24 hours before and 2 hours after each weekly virus exposure. Infection was compared with 21 untreated controls.Results: Five of the 6 animals in the FTC/TAF and 4 of the 9 animals in the TAF alone group were protected against infection (P = .001 and P = .049, respectively). The calculated efficacy of FTC/TAF and TAF was 91% (95% confidence interval [CI], 34.9%-98.8%) and 57.8% (95% CI, -8.7% to 83.6%), respectively. Infection in FTC/TAF but not TAF-treated macaques was delayed relative to controls (P = .005 and P = .114). Median tenofovir diphosphate (TFV-DP) levels in peripheral blood mononuclear cells (PBMCs) were similar among infected and uninfected macaques receiving TAF PrEP (351 and 143 fmols/106 cells, respectively; P = .921).Conclusions: Emtricitabine/TAF provided a level of protection against vaginal challenge similar to FTC/TFV disoproxil fumarate combination in the macaque model. Our results support the clinical evaluation of FTC/TAF for PrEP in women. [ABSTRACT FROM AUTHOR]

Vaginal microbicides containing antiretrovirals (ARVs) have shown to prevent vaginally acquired human immunodeficiency virus (HIV), but these products may not protect women who engage in anal sex. Intravaginal dosing with ARVs has shown to result in drug exposures in rectal tissues, thus raising the possibility of dual compartment protection. To test this concept, we investigated whether intravaginal dosing with emtricitabine (FTC)/tenofovir (TFV) gel, which fully protected macaques against repeated vaginal exposures to simian human immunodeficiency virus (SHIV), protects against rectal SHIV exposures. Pharmacokinetic studies revealed rapid distribution of FTC and TFV to rectal tissues and luminal fluids, albeit at concentrations 1-2 log10 lower than those in the vaginal compartment. Efficacy measurements against repeated rectal SHIV challenges demonstrated a 4.5-fold reduction in risk of infection in macaques that received intravaginal FTC/TFV compared to placebo gel (P = .047; log-rank test). These data support the concept of dual compartment protection by vaginal dosing and warrants developing ARV-based vaginal products with improved bidirectional dosing. [ABSTRACT FROM AUTHOR]

Understanding genetic variation in human immunodeficiency virus (HIV) is clinically and immunologically important for patient treatment and vaccine development. We investigated the longitudinal intra-host genetic variation of HIV in over 3,000 individuals in the US National HIV Surveillance System with at least four reported HIV-1 polymerase (pol) sequences. In this population, we identified 149 putative instances of superinfection (i.e. an individual sequentially infected with genetically divergent, polyphyletic viruses). Unexpectedly, we discovered a group of 240 individuals with consecutively sampled viral strains that were >0.015 substitutions/site divergent, despite remaining monophyletic in the phylogeny. Viruses in some of these individuals had a maximumgenetic divergence approaching that found between two random, unrelated HIV-1 subtype-B pol sequences within the US population. Individuals with these highly divergent viruses tended to be diagnosed nearly a decade earlier in the epidemic than people with superinfection or virus with less intra-host genetic variation, and they had distinct transmission risk factor profiles. To better understand this genetic variation in cases with extremely divergent, monophyletic viruses, we performed molecular clock phylogenetic analysis. Our findings suggest that, like Hepatitis C virus, extremely divergent HIV lineages can be maintained within an individual and reemerge over a period of years. [ABSTRACT FROM AUTHOR]

Tenofovir alafenamide (TAF) is a novel prodrug of tenofovir that efficiently delivers tenofovir diphosphate to lymphoid cells following oral administration. We investigated whether the combination of TAF and emtricitabine (FTC) could prevent simian/human immunodeficiency virus (SHIV) infection in macaques to determine the potential use of TAF for pre-exposure prophylaxis (PrEP) to prevent human immunodeficiency virus infection. Macaques were exposed rectally to SHIV once per week for up to 19 weeks and received saline or FTC/TAF 24 hours before and 2 hours after each virus inoculation. All 6 controls were infected, while the 6 PrEP-treated animals were protected from infection. Our results support the clinical investigation of FTC/TAF for PrEP. [ABSTRACT FROM AUTHOR]

Genital inflammation associated with sexually transmitted infections increases susceptibility to human immunodeficiency virus (HIV), but it is unclear whether the increased risk can reduce the efficacy of pre-exposure prophylaxis (PrEP). We investigated whether coinfection of macaques with Chlamydia trachomatis and Trichomonas vaginalis decreases the prophylactic efficacy of oral emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF). Macaques were exposed to simian/human immunodeficiency virus (SHIV) vaginally each week for up to 16 weeks and received placebo or FTC/TDF pericoitally. All animals in the placebo group were infected with SHIV, while 4 of 6 PrEP recipients remained uninfected (P= .03). Oral FTC/TDF maintains efficacy in a macaque model of sexually transmitted coinfection, although the infection of 2 macaques signals a modest loss of PrEP activity. [ABSTRACT FROM AUTHOR]

Background: Rectal human immunodeficiency virus (HIV) transmission is an important driver of the HIV epidemic. Optimally formulated gels of antiretroviral drugs are under development for preventing rectally acquired HIV. We investigated in a macaque model the pharmacokinetics and efficacy of 3 rectal gel formulationsMethods: Single-dose pharmacokinetics of low-osmolar 1% maraviroc (MVC), 1% tenofovir (TFV), or 1% MVC/1% TFV combination gel were evaluated in blood, rectal fluids, colorectal biopsy specimens, and rectal lymphocytes. Efficacy was evaluated over 10 twice-weekly rectal SHIV162p3 challenges in rhesus macaques that received either placebo (n = 7), MVC (n = 6), TFV (n = 6), or MVC/TFV (n = 6) gel 30 minutes before each challenge.Results: MVC and TFV were detected in plasma 30 minutes after gel application and remained above 95% inhibitory concentrations in rectal fluids at 24 hours. MVC, TFV, and TFV diphosphate (TFV-DP) concentrations in colorectal tissues collected up to 30 cm from the anal margin were all high at 2 hours, demonstrating rapid and extended tissue dosing. TFV-DP concentrations in tissue homogenates and rectal lymphocytes were highly correlated (r(2) = 0.82). All 3 gel formulations were highly protective (82% efficacy; P ≤ .02 by the log-rank test).Conclusions: Desirable pharmacokinetic profiles and high efficacy in this macaque model support the clinical development of these gel formulations for preventing rectal HIV infection. [ABSTRACT FROM AUTHOR]

Objectives: Pharmacokinetic studies in animal models are important for assessing the prophylactic potential of antiretroviral drugs for HIV prevention. This study sought to identify clinically relevant doses of the marketed integrase inhibitors raltegravir, elvitegravir and dolutegravir in macaques and investigate drug penetration and antiviral activity in mucosal secretions. Methods: Macaques received one oral dose of raltegravir, elvitegravir or dolutegravir alone or in combination with emtricitabine and tenofovir disoproxil fumarate followed by drug level measurements in blood and rectal and vaginal secretions. Antiviral activity was investigated in TZM-bl cells exposed to SHIV162p3 in the presence of rectal secretions collected from treated animals. Results: Plasma drug concentrations with 50 mg/kg raltegravir or elvitegravir were within the range seen in humans receiving 400-800 mg of raltegravir or 800 mg of unboosted elvitegravir but lower than with 150 mg of elvitegravir boosted with cobicistat. AUC0-24 values for dolutegravir increased proportionally with the dose, with a calculated human-equivalent dose of 20 mg/kg. Elvitegravir showed the highest penetration in rectal and vaginal fluids despite the absence of pharmacological boosting, followed by raltegravir and dolutegravir. Rectal secretions collected at 24 h from treated macaques blocked infection of TZM-bl cells by 50% at dilutions of 1/1000 (raltegravir), 1/800 (dolutegravir) and >1/30000 (elvitegravir). Conclusions: We defined macaque doses of HIV integrase inhibitors that recapitulate human clinical doses, which will facilitate efficacy and dose escalation studies in macaques. High and sustained drug concentrations and activity in mucosal secretions suggest that integrase inhibitors are promising candidates for HIV prevention. [ABSTRACT FROM AUTHOR]

Objectives This study evaluated the relationship between intracellular tenofovir diphosphate concentrations in peripheral blood mononuclear cells and prophylactic efficacy in a macaque model for HIV pre-exposure prophylaxis (PrEP). Methods Macaques were challenged with simian HIV (SHIV) via rectal inoculation once weekly for up to 14 weeks. A control group (n = 34) received no drug, a second group (n = 6) received oral tenofovir disoproxil fumarate/emtricitabine 3 days before each virus challenge and a third group (n = 6) received the same dosing plus another dose 2 h after virus challenge. PBMCs were collected just before each weekly virus challenge. The relationship between tenofovir diphosphate in PBMCs and prophylactic efficacy was assessed with a Cox proportional hazards model. Results The percentages of animals infected in the control, one-dose and two-dose groups were 97, 83 and 17, respectively. The mean (SD) steady-state tenofovir diphosphate concentration (fmol/106 cells) was 15.8 (7.6) in the one-dose group and 30.7 (10.1) in the two-dose group. Each 5 fmol tenofovir diphosphate/106 cells was associated with a 40% (95% CI 17%–56%) reduction in risk of SHIV acquisition, P = 0.002. The tenofovir diphosphate concentration associated with a 90% reduction in risk (EC90) was 22.6 fmol/106 cells (95% CI 13.8–60.8). Conclusions The prophylactic EC90 for tenofovir diphosphate identified in macaques exposed rectally compares well with the EC90 previously identified in men who have sex with men (MSM; 16 fmol/106 cells, 95% CI 3–28). These results highlight the relevance of this model to inform human PrEP studies of oral tenofovir disoproxil fumarate/emtricitabine for MSM. [ABSTRACT FROM PUBLISHER]

The Centre for the AIDS Programme of Research in South Africa 004 (CAPRISA 004) study demonstrated that vaginally applied tenofovir gel is a promising intervention for protecting women from sexually acquiring human immunodeficiency virus (HIV). However, the potential for emergence of tenofovir resistance remains a concern in women who seroconvert while using the gel despite the lack of plasma virus resistance as assessed by population sequencing during the trial. We applied highly sensitive polymerase chain reaction–based assays to screen for tenofovir resistance in plasma and vaginal swab specimens. The absence of mutation detection suggested little immediate risk of tenofovir-resistant HIV-1 emergence and forward transmission in settings in which gel users are closely monitored for HIV seroconversion. [ABSTRACT FROM AUTHOR]

Daily preexposure prophylaxis (PrEP) with emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) is a novel strategy for preventing human immunodeficiency virus infection. We investigated in macaques whether FTC/TDF prevents transmission of a tenofovir-resistant simian/human immunodeficiency virus (SHIV) containing the K65R mutation. Six macaques received weekly a dose of FTC/TDF 3 days before rectal SHIV exposures and a second dose 2 hours after. Six untreated animals were controls. Animals were exposed rectally to escalating virus doses weekly for up to 28 weeks. PrEP significantly delayed infection with SHIVK65R (P = .028), although 4 of 6 FTC/TDF-treated macaques were infected at the end of the challenges. These findings highlight the need to closely monitor PrEP efficacy in areas with prevalent K65R. [ABSTRACT FROM AUTHOR]

Background.The impact of pre-exposure prophylaxis (PrEP) with antiretrovirals on breakthrough HIV or SHIV infection is not fully documented. We addressed the hypothesis that SHIVSF162P3 infection despite active PrEP results in altered early immune parameters, compared with untreated infection.Methods.Eleven rhesus macaques were infected during repeated, rectal, low-dose SHIVSF162P3 exposures while receiving concurrent oral PrEP (Truvada [n = 2] or GS7340 [n = 4]) or as untreated controls (n = 5). We measured SHIV RNA, inflammatory cytokines, CD4 cells, and SHIV-specific and memory T cells until 20 weeks after peak viremia.Results.SHIV infection during PrEP resulted in 100-fold lower peak viremia and lower IL-15, IL-18, and IL-1Ra levels, compared with controls (P < .05; Wilcoxon rank-sum test). Unlike controls, PrEP-treated macaques showed no significant CD4 cell count reduction during acute infection and developed more SHIV-specific central memory T cells, relative to controls. After in vivo CD8 cell depletion, viral load increased to similar levels, indicating that CD8 cells were critical for viral control in both groups.Conclusions.PrEP with antiretrovirals has beneficial effects on early SHIV infection even when infection is not prevented. Although long-term immune control could not be examined in this SHIV infection model, our results suggest that PrEP results in improved early disease parameters in breakthrough infections. [ABSTRACT FROM AUTHOR]

To substantiate reports of greater emergence of the K65R nucleoside reverse transcriptase inhibitor (NRTI) mutation in human immunodeficiency virus type 1 (HIV-1) subtype C, we examined natural low-level K65R expression in subtype C relative to subtypes B and AE. We used allele-specific polymerase chain reaction to screen HIV-1 amplified by reverse-transcription high-fidelity polymerase chain reaction from subtype C-infected South African women and infants and CRF01(subtype AE) from Thailand; all subjects were NRTI naive. We found low-level K65R of unknown clinical significance in NRTI-naive subtype C-infected women and infants at frequencies above the natural occurrence in subtypes B and AE. The frequent appearance of subtype C frameshift deletions at codon 65 supports a propensity for transcription error in this region. [ABSTRACT FROM AUTHOR]

Frequent infection with zoonotic simian foamy virus (SFV) has been reported among HIV-negative primate hunters in rural Cameroon. Plasma samples obtained from urban commercial sex workers (CSWs; n= 139), patients with sexually transmitted diseases (n = 41), and blood donors (n= 179) in the Democratic Republic of Congo [formerly known as Zaire] and Cameroon were tested for SFV and HIV-1 infection. One CSW and one blood donor were found to be seropositive for both SFV and HIV-1, thereby documenting what are, to our knowledge, the first reported cases of dual SFV and HIV infection. The findings of the present study suggest opportunities for bloodborne and sexual transmission of SFV and highlight the importance of defining the clinical consequences of dual infections. [ABSTRACT FROM AUTHOR]

Conventional sequence analysis detects human immunodeficiency virus (H IV)-1 drug resistance mutations in ∼40% of women shortly after they receive intrapartum single-dose nevirapine (SD-NVP). Using sensitive real- time polymerase chain reaction assays for the K103N and Y181C resistance mutations, we tested genotyped virus before and after SD-NVP in 50 South Mrican women infected with HIV-1 subtype C. By sequence analysis, 40 women had no detectable resistance mutations, and an additional 6 women were negative for Y181C after SD-NVP. We found K103N in 16 (40%) of 40 women and Y181C in 5 (11%) of 46 women at 6-36 weeks postpartum. Clonal sequencing confirmed K103N in 5 of 5 representative samples and Y181C in 4 of 4 samples. Four of the 5 women with newly identified Y181C also had K103N. These findings indicate that resistance mutations emerged in at least 65% of the women after SD-NVP and emphasize the importance of further research to determine the clinical implications. [ABSTRACT FROM AUTHOR]

Some laboratories have detected DNA from the macaque polyomavirus simian virus 40 (SV4O) in human tumors, but possible routes of infection remain unknown. In the present study, an enzyme immunoassay using viruslike particles (VLPs) was used to test 254 zoo workers for antibodies to SV40; 25 zoo workers with direct contact with nonhuman primates and 15 other zoo workers (23% vs. 10%, respectively P = .01) were seropositive for 5V40. Additionally, 5V40 seroreactivity confirmed by competitive-inhibition experiments (i.e., blocked by addition of 5V40 VLPs but not by VLPs for BK virus or JC virus, which are related human polyomaviruses) was increased in zoo workers with direct contact with nonhuman primates (10% vs. 3%, respectively; P = .04). 5V40 seroreactivity therefore may reflect zoonotic exposure. [ABSTRACT FROM AUTHOR]

Background. The prevalence and characteristics of persons with newly diagnosed human immunodeficiency virus (HIV) infections with or without evidence of mutations associated with drug resistance have not been well described. Methods. Drug-naive persons in whom HIV had been diagnosed during the previous 12 months and who did not have acquired immune deficiency syndrome were sequentially enrolled from 39 clinics and testing sites in 10 US cities during 1997-2001. Genotyping was conducted from HIV-amplification products, by automated sequencing. For specimens identified as having mutations previously associated with reduced antiretroviral-drug susceptibility, phenotypic testing was performed. Results. Of 1311 eligible participants, 1082 (83%) were enrolled and successfully tested; 8.3% had reverse transcriptase or major protease mutations associated with reduced antiretroviral-drug susceptibility. The prevalence of these mutations was 11.6% among men who had sex with men but was only 6.1% and 4.7% among women and heterosexual men, respectively. The prevalence was 5.4% and 7.9% among African American and Hispanic participants, respectively, and was 13.0% among whites. Among persons whose sexual partners reportedly took antiretroviral medications, the prevalence was 15.2%. Conclusions. Depending on the characteristics of the patients tested, HIV-genotype testing prior to the initiation of therapy would identify a substantial number of infected persons with mutations associated with reduced antiretroviral-drug susceptibility. [ABSTRACT FROM AUTHOR]

Nucleoside reverse-transcriptase (RT) inhibitors (NRTIs), including lamivudine (3TC) and zidovudine (Zdv), are being evaluated for the treatment of human T cell lymphotropic virus type 1 (HTLV-1)-associated disease. However, information on the susceptibility of HTLV-1 to these drugs is limited. The activity of 5 NRTIs on HTLV-1 RT was evaluated. IC[sub 50] values for Zdv, zalcitabine (ddC), didanosine (ddI), 3TC, and stavudine (d4T) were determined, using an enzymatic assay, for 5 HTLV-1 isolates and for reference wild-type and NRTI-resistant human immunodeficiency virus type 1 (HIV-1). Both HTLV-1 and wild-type HIV-1 were equally susceptible to Zdv, ddC, ddI, and d4T. In contrast, high-level resistance to 3TC was found in all HTLV-1 isolates. The findings support the clinical use of Zdv, ddC, ddI, and d4T but not of 3TC for the antiretroviral treatment of HTLV-1-associated disease. [ABSTRACT FROM AUTHOR]

Studies the presence of porcine endogenous retrovirus (PERV) in plasma samples of pigs and in clinical lots of unheated porcine clotting factor VIII concentrate (Hyate:C). Background of the study; Reverse-transcriptase polymerase reaction testing of PERV RNA in pig serum/plasma samples and Hyate:C; RT activity screening in pig serum/plasma samples and Hyate:C products; PERV envelope subtype analysis; Results; Discussion.

Examines the prevalence of mutations associated with increased antiretroviral drug resistance by testing specimens from HIV-infected persons from 1993 to 1998. Demographic and risk characteristics of HIV seroconverters and those with reverse transcriptase or primary protease mutations; Genotypic and phenotypic results from seroconverters; Transmission of mutations to drug-naive persons.

Virus load based on levels of functional reverse transcriptase (RT) was measured in plasma from 50 human immunodeficiency virus (HIV) type 1-infected persons, in 87 samples from 10 HIV-1 seroconversion panels, and in 100 uninfected persons by use of Amp-RT, an ultrasensitive RT assay. Of the 50 clinical samples, 38 (76%) were Amp-RT positive, while all uninfected controls were negative. Pearson's correlation coefficient of RNA and RT levels was .73 for all samples, .86 for seroconversion samples, and .49 for clinical samples. Calculated ratios of RT activity to virion RNA varied widely during both early and late stages of infection. Mean RT:RNA ratios in 8 seroconversion panels and in 12 (34.3%) of 35 individual clinical samples were significantly lower than the ratio for a reference virus. However, ratios were stable in individual seroconversions over time. These data demonstrate that RT activity can be used to quantitate plasma virus load and provide evidence of different levels of virion-associated RT among HIV-1-infected persons. [ABSTRACT FROM PUBLISHER]

Human immunodeficiency virus (HIV)-2 differs from HIV-1 in its relative lower transmissibility and pathogenicity. To understand the virologic basis of these differences, the nef gene from HIV-2-seropositive persons was analyzed because of its importance for disease progression in the genetically related simian immunodeficiency virus (SIV[MAC]). Proviral nef sequences from 60 HIV-2-infected persons were amplified from peripheral blood lymphocytes, and nef open-reading frames were screened by a transcription and translation assay for the presence of full-length (32- to 36-kDa) or truncated (<32 kDa) Nef proteins. Overall, 6 (10%) of 60 persons had truncated Nef proteins; of these, 5 were among the 36 asymptomatic subjects (13.9%) and only 1 was among the 24 symptomatic subjects (4.2%) (P =.23). The results of this study document the presence of defective nef genes in HIV-2 infections with a prevalence higher than that previously seen in HIV-1-infected cohorts of long-term nonprogressors or patients with AIDS. [ABSTRACT FROM AUTHOR]

In an ultrasensitive assay for reverse transcriptase (RT), an in vitro-transcribed heteropoly-meric RNA sequence was used as a template and polymerase chain reaction (PCR) amplification with Southern blot hybridization served as a detection system for the cDNA reaction product. The assay, called Amp-RT, detected 9 tested retroviruses in unconcentrated culture supernatants diluted 102- to 105-fold. A comparative analysis using human immunodeficiency virus type 1 (HIV-l) revealed that Amp-RT was 100,000 times more sensitive than the standard RT assay, 10,000 times more sensitive than p24 antigen capture and branched DNA assays, and 100 times more sensitive than RT-PCR or TCID50 assays. Analysis of serum specimens from 42 HIV-l-infected persons by Amp-RT showed that 36 samples (85.7%) were RT-positive. In contrast, 41 serum specimens from persons seronegative for HIV-1 and human T lymphotropic virus types I and II were all Amp-RT-negative. [ABSTRACT FROM PUBLISHER]

The transmissibility of human T lymphotropic virus (HTLV) type II from mother to child was investigated. Of 236 women enrolled during pregnancy in a study of mother-to-child transmission of human immunodeficiency virus in 1986–1988, 21 (8.9%) were seropositive for HTLV-I/II. All 21 mothers were infected with HTLV-II by synthetic peptide testing and polymerase chain reaction (PCR). HTLV-II-infected women were older (median age, 34 vs. 28 years), more likely to be black (70% vs. 38%), and more likely to report past or current intravenous drug use (85% vs. 56%) than HTLV-II-uninfected women. Of 20 non-breast-fed infants born to 19 of these HTLV-II-infected women, none had detectable HTLV-II by PCR done on peripheral blood mononuclear cells obtained at birth to 36 months of age. Serologic testing of these infants revealed gradual disappearance of HTLV-I/II antibody. While this study does not rule out the possibility of perinatal HTLV-II transmission, the data suggest that it occurs rarely in the absence of breast-feeding. [ABSTRACT FROM PUBLISHER]

In this article, the author comments on articles "Low-Frequency Nonnucleoside Reverse-Transcriptase Inhibitor (NNRTI)-Resistance Variants Contribute to Failure of Efavirenz-Containing Regimens in Treatment-Experienced Patients," and "Pre-existing Minority Drug-Resistant HIV-1 Variants, Adherence, and Risk of Antiretroviral Treatment Failure." He believes that NNRTI is not detected by bulk sequencing. He adds that results will be beneficial for patient management.

Objectives Dried blood spots (DBS) and dried plasma spots (DPS) are considered convenient alternatives to serum and plasma for HIV drug resistance testing in resource-limited settings. We sought to investigate how extreme conditions could affect the short-term ability to amplify and genotype HIV from DBS. Methods A panel of six matched DPS/DBS was generated using blood collected from HIV-infected donors. Replicate cards were prepared in 903 filter paper using 50 µL of blood and stored at either −20°C or at 37°C/100% humidity. Nucleic acids were extracted at baseline and after 1, 2, 8 and 16 weeks of storage and were amplified and sequenced using an in-house RT-nested PCR method or the ViroSeq assay. Results HIV-1 pol was successfully amplified in all DBS/DPS at baseline and in those stored for up to 16 weeks at −20°C by the in-house assay. In contrast, amplification was rapidly lost during storage at 37°C/100% humidity with only 6/6 and 4/6 DBS specimens amplifiable by the in-house assay at weeks 1 and 2, respectively. Similarly, only two DPS stored at 37°C/100% humidity were amplified by the in-house assay at week 1. Conclusions We show that resistance testing from DBS and DPS is severely compromised after 2 and 1 weeks of storage at 37°C/100% humidity with desiccant, respectively. These findings underscore the importance of temperature and humidity for the efficient genotyping of HIV-1 from DBS and DPS, and reiterate the need to rapidly transport specimens from collection sites to locations that have appropriate storage conditions such as −20°C. [ABSTRACT FROM AUTHOR]

We investigated 21 patients with chronic fatigue syndrome who were identified through the surveillance system of the Centers for Disease Control and Prevention (CDC) in Atlanta for the presence of several human and animal retroviruses. In addition, we evaluated 21 CDC employee controls matched with the patients for age (±5 years), gender, and race. The viruses tested included human T-lymphotropic viruses types I and II; human spuma retrovirus; simian T-lymphotropic virus type I; simian retroviruses types 1, 2, and 3; bovine leukemia virus; feline leukemia virus; and gibbon ape leukemia virus. Samples of peripheral blood lymphocytes and leukocytes from patients and controls were analyzed in a blinded fashion for retroviral sequences; polymerase chain reaction (PCR) amplification assays and Southern blot hybridization to 32P-la-beled internal oligoprobes were used. All PCR assays were optimized for maximal sensitivity on respective infected cell lines or plasmids, and sensitivity controls were included in each experiment. All samples from patients and controls were negative for the tested retroviral sequences. Our data indicate that none of these retroviruses plays an etiologic role or is a cofactor in the chronic fatigue syndrome illnesses of our study population. [ABSTRACT FROM PUBLISHER]