Y RNAs are conserved endogenous RIG-I ligands across RNA virus infection and are targeted by HIV-1.

Pattern recognition receptors (PRRs) protect against microbial invasion by detecting specific molecular patterns found in pathogens and initiating an immune response. Although microbial-derived PRR ligands have been extensively characterized, the contribution and relevance of endogenous ligands to PRR activation remains overlooked. Here, we characterize the landscape of endogenous ligands that engage RIG-I-like receptors (RLRs) upon infection by different RNA viruses. In each infection, several RNAs transcribed by RNA polymerase III (Pol3) specifically engaged RLRs, particularly the family of Y RNAs. Sensing of Y RNAs was dependent on their mimicking of viral secondary structure and their 5'-triphosphate extremity. Further, we found that HIV-1 triggered a VPR-dependent downregulation of RNA triphosphatase DUSP11 in vitro and in vivo, inducing a transcriptome-wide change of cellular RNA 5'-triphosphorylation that licenses Y RNA immunogenicity. Overall, our work uncovers the contribution of endogenous RNAs to antiviral immunity and demonstrates the importance of this pathway in HIV-1 infection.

Drug Resistance Mutation Frequency of Single-Genome Amplification-Derived HIV-1 Polymerase Genomes in the Cerebrospinal Fluid and Plasma of HIV-1-Infected Individuals under Nonsuppressive Therapy.

HIV-1 evolution in the cerebrospinal fluid (CSF) and plasma may result in discordant drug resistance mutations (DRMs) in the compartments. Single-genome amplification (SGA) was used to generate partial HIV-1 polymerase genomes in paired CSF and plasma samples from 12 HIV-1-positive participants in the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) study who were classified as neurocognitively unimpaired or with various degrees of HIV-associated neurocognitive disorders (HAND). Subjects were viremic on combination antiretroviral therapy (cART). HIV-1 DRMs and phylogenetic characteristics were determined using the Stanford HIVdb program and phylogenetic analyses. Individual DRMs were identified more frequently in plasma than in paired CSF (P = 0.0078). Significant differences in the ratios of DRMs in CSF and plasma were found in 3 individuals with HAND (3/7 = 43%). Two HAND subjects (2/7 = 29%) demonstrated one DRM in CSF not identified in paired plasma. Longitudinal analyses (n = 4) revealed significant temporal differences in the ratios of DRMs in the compartments. Statistically significant differences in the frequency of DRMs in the CSF and plasma are readily found in those on nonsuppressive cART. While compartment-based DRM discordance was largely consistent with increased drug-selective pressures in the plasma, overrepresentation of DRMs in the central nervous system (CNS) can occur. Underlying mechanisms of HAND are complex and multifactorial. The clinical impact of DRM discordance on viral persistence and HAND pathogenesis remains unclear and warrants further investigation in larger, longitudinal cohorts.IMPORTANCE Several antiretroviral agents do not efficiently enter the CNS, and independent evolution of HIV-1 viral variants in the CNS and plasma can occur. We used single-genome amplification (SGA) in cross-sectional and longitudinal analyses to uniquely define both the identity and relative proportions of drug resistance mutations (DRMs) on individual HIV-1 polymerase genomes in the cerebrospinal fluid (CSF) and plasma in individuals with incomplete viral suppression and known neurocognitive status. Statistically significant differences in the ratio of DRMs in the CSF and plasma were readily found in those on nonsuppressive cART, and overrepresentation of DRMs in the CNS can occur. Although questions about the clinical significance of DRM discordance remain, in the quest for viral eradication, it is important to recognize that a significant, dynamic, compartment-based DRM ratio imbalance can exist, as it has the potential to go unnoticed in the setting of standard clinical drug resistance testing.

Once-Weekly Oral Dosing of MK-8591 Protects Male Rhesus Macaques From Intrarectal Challenge With SHIV109CP3.

BACKGROUND: MK-8591 (4'-ethynyl-2-fluoro-2'-deoxyadenosine [EFdA]) is a novel reverse transcriptase-translocation inhibitor. METHODS: We assessed MK-8591 as preexposure prophylaxis in the rhesus macaque model of intrarectal challenge with simian/human immunodeficiency virus (SHIV). In study 1, 8 rhesus macaques received 3.9 mg/kg of MK-8591 orally on day 0 and once weekly for the next 14 weeks. Eight controls were treated with vehicle. All rhesus macaques were challenged with SHIV109CP3 on day 6 and weekly for up to 12 challenges or until infection was confirmed. The dose of MK-8591 was reduced to 1.3 and 0.43 mg/kg/week in study 2 and further to 0.1 and 0.025 mg/kg/week in study 3. In studies 2 and 3, each dose was given up to 6 times once weekly, and animals were challenged 4 times once weekly with SHIV109CP3. RESULTS: Control macaques were infected after a median of 1 challenge (range, 1-4 challenges). All treated animals in studies 1 and 2 were protected, consistent with a 41.5-fold lower risk of infection (P < .0001, by the log-rank test). In study 3, at a 0.1-mg/kg dose, 2 rhesus macaques became infected, consistent with a 7.2-fold lower risk of infection (P = .0003, by the log-rank test). The 0.025-mg/kg dose offered no protection. CONCLUSIONS: These data support MK-8591's potential as a preexposure prophylaxis agent.

Islatravir for the treatment and prevention of infection with the human immunodeficiency virus type 1.

PURPOSE OF REVIEW: To discuss the potential role of islatravir (ISL), a novel reverse transcriptase translocation inhibitor, in the treatment and prevention of human immunodeficiency virus type 1 (HIV-1) infection. RECENT FINDINGS: Islatravir (4'-ethynyl-2-fluoro-2'-deoxyadenosine, MK-8591) is a long-acting first-in-class nucleoside reverse transcriptase translocation inhibitor with the potential for versatile dosing routes and dosing intervals. It demonstrated robust antiviral activity when dosed once daily and once weekly in HIV-1-infected individuals and SIV-infected rhesus macaques. In clinical trials of ISL in combination with doravirine and lamivudine, daily oral administration resulted in high levels of virologic suppression in HIV-infected individuals. In preclinical studies, ISL dosed orally once-weekly as preexposure prophylaxis (PrEP), protected rhesus macaques against SHIV infection via the mucosal route in the low-dose rectal challenge model. Most recently, data in healthy HIV-1-uninfected individuals demonstrated the feasibility of formulating of ISL as an implant. In these studies, levels of intracellular ISL-triphosphate were consistent with the potential for a once-yearly implantable administration of ISL as PrEP. SUMMARY: Islatravir is a promising new agent for both the treatment and prevention of HIV-1 infection.

Poly-ICLC, a TLR3 Agonist, Induces Transient Innate Immune Responses in Patients With Treated HIV-Infection: A Randomized Double-Blinded Placebo Controlled Trial.

Objective: Toll-like receptor-3 agonist Poly-ICLC has been known to activate immune cells and induce HIV replication in pre-clinical experiments. In this study we investigated if Poly-ICLC could be used for disrupting HIV latency while simultaneously enhancing innate immune responses. Design: This was a randomized, placebo-controlled, double-blinded trial in aviremic, cART-treated HIV-infected subjects. Participants (n = 15) were randomized 3:1 to receive two consecutive daily doses of Poly-ICLC (1.4 mg subcutaneously) vs. placebo. Subjects were observed for adverse events, immune activation, and viral replication. Methods: Besides primary outcomes of safety and tolerability, several longitudinal immune parameters were evaluated including immune cell phenotype and function via flowcytometry, ELISA, and transcriptional profiling. PCR assays for plasma HIV-1 RNA, CD4+ T cell-associated HIV-1 RNA, and proviral DNA were performed to measure HIV reservoirs and latency. Results: Poly-ICLC was overall safe and well-tolerated. Poly-ICLC-related adverse events were Grade 1/2, with the exception of one Grade 3 neutropenia which was short-lived. Mild Injection site reactions were observed in nearly all participants in the Poly-ICLC arm. Transcriptional analyses revealed upregulation of innate immune pathways in PBMCs following Poly-ICLC treatment, including strong interferon signaling accompanied by transient increases in circulating IP-10 (CXCL10) levels. These responses generally peaked by 24-48 h after the first injection and returned to baseline by day 8. CD4+ T cell number and phenotype were unchanged, plasma viral control was maintained and no significant effect on HIV reservoirs was observed. Conclusions: These finding suggest that Poly-ICLC could be safely used for inducing transient innate immune responses in treated HIV+ subjects indicating promise as an adjuvant for HIV therapeutic vaccines. Trial Registration: www.ClinicalTrials.gov, identifier: NCT02071095.

Modelling the Epidemiological Impact and Cost-Effectiveness of PrEP for HIV Transmission in MSM in China.

Risk of HIV infection is high in Chinese MSM, with an annual HIV incidence ranging from 3.41 to 13.7/100 person-years. Tenofovir-based PrEP is effective in preventing HIV transmission in MSM. This study evaluates the epidemiological impact and cost-effectiveness of implementing PrEP in Chinese MSM over the next two decades. A compartmental model for HIV was used to forecast the impact of PrEP on number of infections, deaths, and disability-adjusted life years (DALY) averted. We also provide an estimate of the incremental cost-effectiveness ratio (ICER) and the cost per DALY averted of the intervention. Without PrEP, there will be 1.1-3.0 million new infections and 0.7-2.3 million HIV-related deaths in the next two decades. Moderate PrEP coverage (50%) would prevent 0.17-0.32 million new HIV infections. At Truvada's current price in China, daily oral PrEP costs $46,813-52,008 per DALY averted and is not cost-effective; on-demand Truvada reduces ICER to $25,057-27,838 per DALY averted, marginally cost-effective; daily generic tenofovir-based regimens further reduce ICER to $3675-8963, wholly cost-effective. The cost of daily oral Truvada PrEP regimen would need to be reduced by half to achieve cost-effectiveness and realize the public health good of preventing hundreds of thousands of HIV infections among MSM in China.

Satisfaction and acceptability of cabotegravir long-acting injectable suspension for prevention of HIV: Patient perspectives from the ECLAIR trial.

BACKGROUND: Cabotegravir (GSK1265744) is an integrase strand transfer inhibitor in development as a long-acting (LA) intramuscular injectable suspension for HIV-1 pre-exposure prophylaxis (PrEP). OBJECTIVE: We report participant outcomes from the phase IIa ECLAIR study related to tolerability, acceptability, and satisfaction of cabotegravir LA. METHODS: The ECLAIR study (ClinicalTrials.gov identifier, NCT02076178) was a randomized, placebo-controlled study in healthy men not at high risk of acquiring HIV-1. Participants were randomized (5:1) to once-daily oral cabotegravir 30 mg or placebo tablets for 4 weeks, followed by gluteal intramuscular injections of cabotegravir LA 800 mg or saline placebo every 12 weeks. The primary objective was to evaluate the safety of cabotegravir LA over three injection cycles (to Week 41). Secondary objectives assessed the tolerability, satisfaction, and acceptability of cabotegravir LA. RESULTS: Among 115 participants who received injections in the cabotegravir (n = 94) and placebo (n = 21) groups, 93% (n = 87) and 95% (n = 20) completed the injection phase, respectively. Injection intolerability led to withdrawal in 4 participants (4%) receiving cabotegravir LA. The most frequently reported Grade ≥2 adverse event was injection-site pain. Most participants (74% [n = 67]) receiving consecutive injections favored cabotegravir LA vs oral cabotegravir. Most participants were satisfied with cabotegravir LA (75% [n = 64]), were willing to continue (79% [n = 68]), and would recommend (87% [n = 75]) the therapy. CONCLUSIONS: While Grade ≥2 injection-site pain was common, most participants reported overall satisfaction with and preference for cabotegravir LA, with few discontinuations due to injection intolerance. These findings support investigation of cabotegravir LA as an alternative to daily oral PrEP regimens.

4'-Ethynyl-2-fluoro-2'-deoxyadenosine, MK-8591: a novel HIV-1 reverse transcriptase translocation inhibitor.

PURPOSE OF REVIEW: 4'-Ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) is a nucleoside reverse transcriptase inhibitor (NRTI) with a novel mechanism of action, unique structure, and amongst NRTIs, unparalleled anti-HIV-1 activity. We will summarize its structure and function, antiviral activity, resistance profile, and potential as an antiretroviral for use in the treatment and preexposure prophylaxis of HIV-1 infection. RECENT FINDINGS: EFdA is active against wild-type (EC50 as low as 50 pmol/l) and most highly NRTI-resistant viruses. The active metabolite, EFdA-triphosphate, has been shown to have a prolonged intracellular half-life in human and rhesus (Rh) blood cells. As a result, single drug doses tested in simian immunodeficiency virus mac251-infected Rh macaques and HIV-1-infected individuals exhibited robust antiviral activity of 7-10 days duration. Preclinical studies of EFdA as preexposure prophylaxis in the Rh macaque/simian/human immunodeficiency virus low-dose intrarectal challenge model have shown complete protection when given in clinically relevant doses. SUMMARY: EFdA is a novel antiretroviral with activity against both wild-type and NRTI-resistant viruses. As a result of the prolonged intracellular half-life of its active moiety, it is amenable to flexibility in dosing of at least daily to weekly and perhaps longer.

5' Rapid Amplification of cDNA Ends and Illumina MiSeq Reveals B Cell Receptor Features in Healthy Adults, Adults With Chronic HIV-1 Infection, Cord Blood, and Humanized Mice.

Using 5' rapid amplification of cDNA ends, Illumina MiSeq, and basic flow cytometry, we systematically analyzed the expressed B cell receptor (BCR) repertoire in 14 healthy adult PBMCs, 5 HIV-1+ adult PBMCs, 5 cord blood samples, and 3 HIS-CD4/B mice, examining the full-length variable region of µ, γ, α, κ, and λ chains for V-gene usage, somatic hypermutation (SHM), and CDR3 length. Adding to the known repertoire of healthy adults, Illumina MiSeq consistently detected small fractions of reads with high mutation frequencies including hypermutated µ reads, and reads with long CDR3s. Additionally, the less studied IgA repertoire displayed similar characteristics to that of IgG. Compared to healthy adults, the five HIV-1 chronically infected adults displayed elevated mutation frequencies for all µ, γ, α, κ, and λ chains examined and slightly longer CDR3 lengths for γ, α, and λ. To evaluate the reconstituted human BCR sequences in a humanized mouse model, we analyzed cord blood and HIS-CD4/B mice, which all lacked the typical SHM seen in the adult reference. Furthermore, MiSeq revealed identical unmutated IgM sequences derived from separate cell aliquots, thus for the first time demonstrating rare clonal members of unmutated IgM B cells by sequencing.

Cabotegravir in the treatment and prevention of Human Immunodeficiency Virus-1.

INTRODUCTION: Human Immunodeficiency Virus (HIV) is a chronic infection that depletes the immune system of essential components causing those infected to be at risk for multiple life-threatening infections. Worldwide, millions live with this infection, the vast majority attributable to HIV-1. Transmission persists with hundreds of thousands of new infections reported yearly. Implementation of combination antiretroviral therapy (cART) has been effective in improving outcomes and decreasing transmission. Newer co-formulated agents have provided simpler medication regimens, fewer side effects, and, in some cases, a higher barrier to the emergence of medication resistance. Areas covered: Here, we review trials of cabotegravir (CAB) as treatment of HIV-1 infection and its potential use as pre-exposure prophylaxis (PrEP) in high risk individuals, including issues around oral lead in and potential resistance emergence. Expert opinion: CAB is efficacious when used in combination therapy orally or given intramuscularly every 4 to 8 weeks. Its availability in a long-acting injectable formulation (CAB-LA) makes it a valuable, novel drug to treat HIV-1 infection when combined with long-acting injectable rilpivirine (RPV-LA). Moreover, pre-clinical and early Phase 2a studies support its testing as monotherapy as PrEP. Studies are underway comparing the efficacy of every 8 week CAB-LA to tenofovir disoproxil fumarate/emtricitabine (TDF/FTC).

Lessons for Patient Education Around Long-Acting Injectable PrEP: Findings from a Mixed-Method Study of Phase II Trial Participants.

This study aimed to identify patients' physical and psychosocial experiences of an investigational long-acting injectable PrEP product to aid in the development of patient and provider education materials. Twenty-eight participants of a Phase 2 safety, tolerability, and acceptability study of long-acting integrase inhibitor cabotegravir (CAB-LA) were interviewed on their physical and psychosocial experiences of the injections. Five themes emerged through a framework analysis on these interview transcripts: (1) injection-related pain is highly variable across individuals; (2) pain is more impactful after the injections than during; (3) patient anxiety is critical, but does not determine the experience of injections and decreases over time; (4) intimacy and awkwardness of gluteal injections impacts patients' experiences; (5) patient education and care strategies can mitigate the above factors. These findings can inform further sociobehavioral research within Phase 3 efficacy trials of CAB-LA, as well as patient education and provider guidance for future injectable PrEP products.

Safety and tolerability of long-acting cabotegravir injections in HIV-uninfected men (ECLAIR): a multicentre, double-blind, randomised, placebo-controlled, phase 2a trial.

BACKGROUND: Cabotegravir (GSK1265744) is an HIV-1 integrase strand transfer inhibitor with potent antiviral activity and a long half-life when administered by injection that prevented simian-HIV infection upon repeat intrarectal challenge in male macaques. We aimed to assess the safety, tolerability, and pharmacokinetics of long-acting cabotegravir injections in healthy men not at high risk of HIV-1 infection. METHODS: We did this multicentre, double-blind, randomised, placebo-controlled, phase 2a trial at ten sites in the USA. Healthy men (aged 18-65 years) deemed not at high risk of acquiring HIV-1 at screening were randomly assigned (5:1), via computer-generated central randomisation schedules, to receive cabotegravir or placebo. Participants received oral cabotegravir 30 mg tablets or matching placebo once daily during a 4 week oral lead-in phase, followed by a 1 week washout period and, after safety assessment, three intramuscular injections of long-acting cabotegravir 800 mg or saline placebo at 12 week intervals. Study site staff and participants were masked to treatment assignment from enrolment through week 41 (time of the last injection). The primary endpoint was safety and tolerability from the first injection (week 5) to 12 weeks after the last injection. We did analysis in the safety population, defined as all individuals enrolled in the study who received at least one dose of the study drug. This study is registered with ClinicalTrials.gov identifier, NCT02076178. FINDINGS: Between March 27, 2014, and Feb 23, 2016, we randomly assigned 127 participants to receive cabotegravir (n=106) or placebo (n=21); 126 (99%) participants comprised the safety population. Most participants were men who have sex with men (MSM; n=106 [83%]) and white (n=71 [56%]). 87 (82%) participants in the cabotegravir group and 20 (95%) participants in the placebo group completed the injection phase. Adverse events (n=7 [7%]) and injection intolerability (n=4 [4%]) were the main reasons for withdrawal in the cabotegravir group. The frequency of grade 2 or higher adverse events was higher in participants in the long-acting cabotegravir group (n=75 [80%]) than in those in the placebo group (n=10 [48%]; p=0·0049), mostly due to injection-site pain (n=55 [59%]). No significant differences were noted in concomitant medications, laboratory abnormalities, electrocardiogram, and vital sign assessments. Geometric mean trough plasma concentrations were 0·302 µg/mL (95% CI 0·237-0·385), 0·331 µg/mL (0·253-0·435), and 0·387 µg/mL (0·296-0·505) for injections one, two, and three, respectively, indicating lower than predicted exposure. The geometric mean apparent terminal phase half-life estimated after the third injection was 40 days. Two (2%) MSM acquired HIV-1 infection, one in the placebo group during the injection phase and one in the cabotegravir group 24 weeks after the final injection when cabotegravir exposure was well below the protein-binding-adjusted 90% inhibitory concentration. INTERPRETATION: Despite high incidence of transient, mild-to-moderate injection-site reactions, long-acting cabotegravir was well tolerated with an acceptable safety profile. Pharmacokinetic data suggest that 800 mg administered every 12 weeks is a suboptimal regimen; alternative dosing strategies are being investigated. Our findings support further investigation of long-acting injectable cabotegravir as an alternative to orally administered pre-exposure prophylaxis regimens. FUNDING: ViiV Healthcare.

Brief Report: The Relationship Between Injection Drug Use Risk Behaviors and Markers of Immune Activation.

High levels of immune activation are reported for people who inject drugs. Studies of the relationship between injection behaviors and immune activation have yielded mixed results, in part due to lack of control for hepatitis C virus in analyses. This study, of 48 HIV-seronegative people who inject drugs, examines this relationship controlling for hepatitis C virus viremia. Frequency of injection was positively related to markers of immune activation (soluble CD14, %CD8CD38HLADR T cells), as was duration of injection (high-specificity C-reactive protein and D-dimer). Sharing injection equipment was not related to markers studied. Findings suggest that efforts to encourage injection cessation or reduction in frequency can have positive health benefits through reducing immune activation.

Cabotegravir long acting injection protects macaques against intravenous challenge with SIVmac251.

OBJECTIVE: We evaluated the effectiveness of cabotegravir (CAB; GSK1265744 or GSK744) long acting as preexposure prophylaxis (PrEP) against intravenous simian immunodeficiency virus (SIV) challenge in a model that mimics blood transfusions based on the per-act probability of infection. DESIGN: CAB long acting is an integrase strand transfer inhibitor formulated as a 200 mg/ml injectable nanoparticle suspension that is an effective PrEP agent against rectal and vaginal simian/human immunodeficiency virus transmission in macaques. METHODS: Three groups of rhesus macaques (n = 8 per group) were injected intramuscularly with CAB long acting and challenged intravenously with 17 animal infectious dose 50% SIVmac251 on week 2. Group 1 was injected with 50 mg/kg on week 0 and 4 to evaluate the protective efficacy of the CAB long-acting dose used in macaque studies mimicking sexual transmission. Group 2 was injected with 50 mg/kg on week 0 to evaluate the necessity of the second injection of CAB long acting for protection against intravenous challenge. Group 3 was injected with 25 mg/kg on week 0 and 50 mg/kg on week 4 to correlate CAB plasma concentrations at the time of challenge with protection. Five additional macaques remained untreated as controls. RESULTS: CAB long acting was highly protective with 21 of the 24 CAB long-acting-treated macaques remaining aviremic, resulting in 88% protection. The plasma CAB concentration at the time of virus challenge appeared to be more important for protection than sustaining therapeutic plasma concentrations with the second CAB long acting injection. CONCLUSION: These results support the clinical investigation of CAB long acting as PrEP in people who inject drugs.

Challenges in Recruiting People Who Use Drugs for HIV-Related Biomedical Research: Perspectives from the Field.

Recruitment of people who use drugs (PWUD) for HIV-related research has been undertaken since early in the epidemic. In early studies, recruitment was often performed by outreach workers with familiarity with the target population, who distributed risk reduction materials, and administered the surveys being conducted on drug use and risk behaviors. The evolution of effective treatments for HIV has provided opportunities for PWUD to participate in biobehavioral studies testing the efficacy of medical treatment advances and exploring the underlying biomedical basis for prevention and treatment efforts. Recruitment for these studies has led to new challenges for outreach workers and institutions conducting this research. PWUD, particularly those from race/ethnic minority populations, have had lower rates of engagement in HIV care and have been underrepresented in HIV/AIDS medical studies. To address these health disparities, enhanced efforts are needed to increase their participation in biomedical studies. This article examines the challenges identified by experienced outreach workers in recruiting PWUD for HIV-related biomedical studies, including individual (participant)-, institutional-, and recruiter-level challenges, and provides recommendations for addressing them.

Chronic Hepatitis C Virus Infection and the Proinflammatory Effects of Injection Drug Use.

BACKGROUND: Chronic inflammation, as defined by persistent immune activation, is associated with adverse clinical outcomes. People who inject drugs (PWID) have evidence of persistent immune activation. Here, in a cohort of PWID with or without hepatitis C virus (HCV) infection, we sought to dissect out the contribution of chronic HCV infection (common in PWID) from the effects of injection drug use itself. METHODS: Four groups of study volunteers were recruited: group 1 comprised active PWID; group 2, individuals who ceased injecting drugs 1-2 months before recruitment; group 3, individuals who ceased injecting drugs 3-4 months before recruitment; and group 4, healthy volunteers. Soluble and cell-associated markers of immune activation were quantified. RESULTS: HCV-viremic PWID have elevated levels of immune activation when compared to healthy volunteers. Cessation of injection drug use results in a decline in immune activation in the absence of HCV viremia, while HCV-viremic individuals who previously were PWID continue to harbor elevated levels of immune activation, as defined by increased levels of soluble CD14 and tumor necrosis factor α and by the presence of CD38+HLA-DR+ CD4+ and CD8+ T cells. CONCLUSIONS: Immune activation, a well-defined surrogate of poor clinical outcome that is elevated in PWID, can regress to normal levels in former injection drug users who are HCV aviremic. Therefore, enhanced harm-reduction efforts should incorporate aggressive treatment of HCV infection. CLINICAL TRIALS REGISTRATION: NCT01831284.

Development of Broadly Neutralizing Antibodies and Their Mapping by Monomeric gp120 in Human Immunodeficiency Virus Type 1-Infected Humans and Simian-Human Immunodeficiency Virus SHIVSF162P3N-Infected Macaques.

UNLABELLED: To improve our understanding of the similarities and differences between neutralizing antibodies elicited by simian-human immunodeficiency virus (SHIV)-infected rhesus macaques and human immunodeficiency virus type 1 (HIV-1)-infected humans, we examined the plasma of 13 viremic macaques infected with SHIVSF162P3Nand 85 HIV-1-infected humans with known times of infection. We identified 5 macaques (38%) from 1 to 2 years postinfection (p.i.) with broadly neutralizing antibodies (bnAbs) against tier 2 HIV-1. In comparison, only 2 out of 42 (5%) human plasma samples collected in a similar time frame of 1 to 3 years p.i. exhibited comparable neutralizing breadths and potencies, with the number increasing to 7 out of 21 (30%) after 3 years p.i. Plasma mapping with monomeric gp120 identified only 2 out of 9 humans and 2 out of 4 macaques that contained gp120-reactive neutralizing antibodies, indicating distinct specificities in these plasma samples, with most of them recognizing the envelope trimer (including gp41) rather than the gp120 monomer. Indeed, a total of 20 gp120-directed monoclonal antibodies (MAbs) isolated from a human subject (AD358) and a Chinese rhesus macaque (GB40) displayed no or limited neutralizing activity against tier 2 strains. These isolated MAbs, mapped to the CD4-binding site, the V3 loop, the inner domain, and the C5 region of gp120, revealed genetic similarity between the human and macaque immunoglobulin genes used to encode some V3-directed MAbs. These results also support the use of envelope trimer probes for efficient isolation of HIV-1 bnAbs. IMPORTANCE: HIV-1 vaccine research can benefit from understanding the development of broadly neutralizing antibodies (bnAbs) in rhesus macaques, commonly used to assess vaccine immunogenicity and efficacy. Here, we examined 85 HIV-1-infected humans and 13 SHIVSF162P3N-infected macaques for bnAbs and found that, similar to HIV-1-infected humans, bnAbs in SHIV-infected macaques are also rare, but their development might have been faster in some of the studied macaques. Plasma mapping with monomeric gp120 indicated that most bnAbs bind to the envelope trimer rather than the gp120 monomer. In support of this, none of the isolated gp120-reactive monoclonal antibodies (MAbs) displayed the neutralization breadth observed in the corresponding plasma. However, the MAb sequences revealed similarity between human and macaque genes used to encode some V3-directed MAbs. Our study sheds light on the timing and development of bnAbs in SHIV-infected macaques in comparison to HIV-1-infected humans and highlights the use of envelope trimer probes for efficient recovery of bnAbs.

Population-Level Immune-Mediated Adaptation in HIV-1 Polymerase during the North American Epidemic.

UNLABELLED: Human leukocyte antigen (HLA) class I-associated polymorphisms in HIV-1 that persist upon transmission to HLA-mismatched hosts may spread in the population as the epidemic progresses. Transmission of HIV-1 sequences containing such adaptations may undermine cellular immune responses to the incoming virus in future hosts. Building upon previous work, we investigated the extent of HLA-associated polymorphism accumulation in HIV-1 polymerase (Pol) through comparative analysis of linked HIV-1/HLA class I genotypes sampled during historic (1979 to 1989; n = 338) and modern (2001 to 2011; n = 278) eras from across North America (Vancouver, BC, Canada; Boston, MA; New York, NY; and San Francisco, CA). Phylogenies inferred from historic and modern HIV-1 Pol sequences were star-like in shape, with an inferred most recent common ancestor (epidemic founder virus) sequence nearly identical to the modern North American subtype B consensus sequence. Nevertheless, modern HIV-1 Pol sequences exhibited roughly 2-fold-higher patristic (tip-to-tip) genetic distances than historic sequences, with HLA pressures likely driving ongoing diversification. Moreover, the frequencies of published HLA-associated polymorphisms in individuals lacking the selecting HLA class I allele was on average ∼2.5-fold higher in the modern than in the historic era, supporting their spread in circulation, though some remained stable in frequency during this time. Notably, polymorphisms restricted by protective HLA alleles appear to be spreading to a greater relative extent than others, though these increases are generally of modest absolute magnitude. However, despite evidence of polymorphism spread, North American hosts generally remain at relatively low risk of acquiring an HIV-1 polymerase sequence substantially preadapted to their HLA profiles, even in the present era. IMPORTANCE: HLA class I-restricted cytotoxic T-lymphocyte (CTL) escape mutations in HIV-1 that persist upon transmission may accumulate in circulation over time, potentially undermining host antiviral immunity to the transmitted viral strain. We studied >600 experimentally collected HIV-1 polymerase sequences linked to host HLA information dating back to 1979, along with phylogenetically reconstructed HIV-1 sequences dating back to the virus' introduction into North America. Overall, our results support the gradual spread of many-though not all-HIV-1 polymerase immune escape mutations in circulation over time. This is consistent with recent observations from other global regions, though the extent of polymorphism accumulation in North America appears to be lower than in populations with high seroprevalence, older epidemics, and/or limited HLA diversity. Importantly, the risk of acquiring an HIV-1 polymerase sequence at transmission that is substantially preadapted to one's HLA profile remains relatively low in North America, even in the present era.