Non-neutralizing Antibodies Alter the Course of HIV-1 Infection In Vivo.

Non-neutralizing antibodies (nnAbs) to HIV-1 show little measurable activity in prevention or therapy in animal models yet were the only correlate of protection in the RV144 vaccine trial. To investigate the role of nnAbs on HIV-1 infection in vivo, we devised a replication-competent HIV-1 reporter virus that expresses a heterologous HA-tag on the surface of infected cells and virions. Anti-HA antibodies bind to, but do not neutralize, the reporter virus in vitro. However, anti-HA protects against infection in humanized mice and strongly selects for nnAb-resistant viruses in an entirely Fc-dependent manner. Similar results were also obtained with tier 2 HIV-1 viruses using a human anti-gp41 nnAb, 246D. While nnAbs are demonstrably less effective than broadly neutralizing antibodies (bNAbs) against HIV-1 in vitro and in vivo, the data show that nnAbs can protect against and alter the course of HIV-1 infection in vivo. PAPERCLIP.

Broadly neutralizing antibodies and viral inducers decrease rebound from HIV-1 latent reservoirs in humanized mice.

Latent reservoirs of HIV-1-infected cells are refractory to antiretroviral therapies (ART) and remain the major barrier to curing HIV-1. Because latently infected cells are long-lived, immunologically invisible, and may undergo homeostatic proliferation, a "shock and kill" approach has been proposed to eradicate this reservoir by combining ART with inducers of viral transcription. However, all attempts to alter the HIV-1 reservoir in vivo have failed to date. Using humanized mice, we show that broadly neutralizing antibodies (bNAbs) can interfere with establishment of a silent reservoir by Fc-FcR-mediated mechanisms. In established infection, bNAbs or bNAbs plus single inducers are ineffective in preventing viral rebound. However, bNAbs plus a combination of inducers that act by independent mechanisms synergize to decrease the reservoir as measured by viral rebound. Thus, combinations of inducers and bNAbs constitute a therapeutic strategy that impacts the establishment and maintenance of the HIV-1 reservoir in humanized mice.

Combination therapy with anti-HIV-1 antibodies maintains viral suppression.

Individuals infected with HIV-1 require lifelong antiretroviral therapy, because interruption of treatment leads to rapid rebound viraemia. Here we report on a phase 1b clinical trial in which a combination of 3BNC117 and 10-1074, two potent monoclonal anti-HIV-1 broadly neutralizing antibodies that target independent sites on the HIV-1 envelope spike, was administered during analytical treatment interruption. Participants received three infusions of 30 mg kg-1 of each antibody at 0, 3 and 6 weeks. Infusions of the two antibodies were generally well-tolerated. The nine enrolled individuals with antibody-sensitive latent viral reservoirs maintained suppression for between 15 and more than 30 weeks (median of 21 weeks), and none developed viruses that were resistant to both antibodies. We conclude that the combination of the anti-HIV-1 monoclonal antibodies 3BNC117 and 10-1074 can maintain long-term suppression in the absence of antiretroviral therapy in individuals with antibody-sensitive viral reservoirs.

HIV-1 antibody 3BNC117 suppresses viral rebound in humans during treatment interruption.

Interruption of combination antiretroviral therapy in HIV-1-infected individuals leads to rapid viral rebound. Here we report the results of a phase IIa open label clinical trial evaluating 3BNC117,a broad and potent neutralizing antibody against the CD4 binding site of the HIV-1 Env protein, during analytical treatment interruption in 13 HIV-1-infected individuals. Participants with 3BNC117-sensitive virus outgrowth cultures were enrolled. Results show that two or four 30 mg kg(-1) 3BNC117 infusions,separated by 3 or 2 weeks, respectively, are generally well tolerated.Infusions are associated with a delay in viral rebound of 5-9 weeks after two infusions, and up to 19 weeks after four infusions, or an average of 6.7 and 9.9 weeks, respectively, compared with 2.6 weeks for historical controls (P < 0.00001). Rebound viruses arise predominantly from a single provirus. In most individuals,emerging viruses show increased resistance, indicating escape.However, 30% of participants remained suppressed until antibody concentrations waned below 20 µg ml(-1), and the viruses emerging in all but one of these individuals showed no apparent resistance to 3BCN117, suggesting failure to escape over a period of 9-19 weeks.We conclude that the administration of 3BNC117 exerts strong selective pressure on HIV-1 emerging from latent reservoirs during analytical treatment interruption in humans.

Relationship between intact HIV-1 proviruses in circulating CD4+ T cells and rebound viruses emerging during treatment interruption.

Combination antiretroviral therapy controls but does not cure HIV-1 infection because a small fraction of cells harbor latent viruses that can produce rebound viremia when therapy is interrupted. The circulating latent virus reservoir has been documented by a variety of methods, most prominently by viral outgrowth assays (VOAs) in which CD4+ T cells are activated to produce virus in vitro, or more recently by amplifying proviral near full-length (NFL) sequences from DNA. Analysis of samples obtained in clinical studies in which individuals underwent analytical treatment interruption (ATI), showed little if any overlap between circulating latent viruses obtained from outgrowth cultures and rebound viruses from plasma. To determine whether intact proviruses amplified from DNA are more closely related to rebound viruses than those obtained from VOAs, we assayed 12 individuals who underwent ATI after infusion of a combination of two monoclonal anti-HIV-1 antibodies. A total of 435 intact proviruses obtained by NFL sequencing were compared with 650 latent viruses from VOAs and 246 plasma rebound viruses. Although, intact NFL and outgrowth culture sequences showed similar levels of stability and diversity with 39% overlap, the size of the reservoir estimated from NFL sequencing was larger than and did not correlate with VOAs. Finally, intact proviruses documented by NFL sequencing showed no sequence overlap with rebound viruses; however, they appear to contribute to recombinant viruses found in plasma during rebound.

Characterization of Intact Proviruses in Blood and Lymph Node from HIV-Infected Individuals Undergoing Analytical Treatment Interruption.

The role of lymphoid tissue as a potential source of HIV-1 rebound following interruption of antiretroviral therapy (ART) is uncertain. To address this issue, we compared the latent viruses obtained from CD4+ T cells in peripheral blood and lymph nodes to viruses emerging during treatment interruption. Latent viruses were characterized by sequencing near-full-length (NFL) proviral DNA and env from viral outgrowth assays (VOAs). Five HIV-1-infected individuals on ART were studied, four of whom participated in a clinical trial of a TLR9 agonist that included an analytical treatment interruption. We found that 98% of intact or replication-competent clonal sequences overlapped between blood and lymph node. In contrast, there was no overlap between 205 latent reservoir and 125 rebound sequences in the four individuals who underwent treatment interruption. However, rebound viruses could be accounted for by recombination. The data suggest that CD4+ T cells carrying latent viruses circulate between blood and lymphoid tissues in individuals on ART and support the idea that recombination may play a role in the emergence of rebound viremia.IMPORTANCE HIV-1 persists as a latent infection in CD4+ T cells that can be found in lymphoid tissues in infected individuals during ART. However, the importance of this tissue reservoir and its contribution to viral rebound upon ART interruption are not clear. In this study, we sought to compare latent HIV-1 from blood and lymph node CD4+ T cells from five HIV-1-infected individuals. Further, we analyzed the contribution of lymph node viruses to viral rebound. We observed that the frequencies of intact proviruses were the same in blood and lymph node. Moreover, expanded clones of T cells bearing identical proviruses were found in blood and lymph node. These latent reservoir sequences did not appear to be the direct origin of rebound virus. Instead, latent proviruses were found to contribute to the rebound compartment by recombination.

Comparative effectiveness of two doses versus three doses of hepatitis A vaccine in human immunodeficiency virus-infected and -uninfected men who have sex with men.

UNLABELLED: The purpose of this prospective cohort study was to compare the serologic response between human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) receiving two and three doses of hepatitis A virus (HAV) vaccine and HIV-uninfected MSM receiving two doses of HAV vaccine. Between June 2009 and December 2010, 582 MSM aged 18 to 40 years who were seronegative for HAV were enrolled in the study. HIV-infected MSM received either two doses of HAV vaccine (1,440 enzyme-linked immunosorbent assay units) (n = 140) with the second dose given at week 24 or three doses (n = 225) with the second and third dose given at weeks 4 and 24, respectively, while HIV-uninfected MSM (n = 217) received two doses. The primary endpoint was seroconversion at week 48. The geometric mean concentration (GMC) of anti-HAV antibody was determined at weeks 48 and 72. At week 48, the seroconversion rate was 75.7%, 77.8%, and 88.5% in intention-to-treat analysis for two-dose HIV-infected, three-dose HIV-infected, and two-dose HIV-uninfected MSM, respectively. The GMC of anti-HAV antibody at week 48 for three-dose HIV-infected MSM (2.29 ± 0.73 log10 mIU/mL) was significantly higher than that for two-dose HIV-infected MSM (1.94 ± 0.66; P < 0.01), but was lower than HIV-uninfected MSM (2.49 ± 0.42; P < 0.01). Multivariate analysis revealed higher CD4 counts (adjusted odds ratio [AOR] for per 50 cells/µL increase, 1.13; 95% confidence interval [CI], 1.05-1.21) and undetectable plasma HIV RNA load (AOR, 1.90; 95% CI, 1.10-3.28) before HAV vaccination were predictive of seroconversion in HIV-infected patients. CONCLUSION: Serologic response rate to three and two doses of HAV vaccine was similar in HIV-infected MSM, which was lower than that in HIV-uninfected MSM receiving two doses. HAV vaccination in HIV-infected patients with a higher CD4 count and suppression of HIV replication increased the seroconversion rate.

Recent hepatitis C virus infections in HIV-infected patients in Taiwan: incidence and risk factors.

Outbreaks of sexually transmitted hepatitis C virus (HCV) infections have been recently reported in HIV-infected men who have sex with men (MSM) in Europe, Australia, and North America. Little is known concerning whether this also occurs in other Asia-Pacific countries. Between 1994 and 2010, a prospective observational cohort study was performed to assess the incidence of recent HCV seroconversion in 892 HIV-infected patients (731 MSM and 161 heterosexuals) who were not injecting drug users. A nested case-control study was conducted to identify associated factors with recent HCV seroconversion, and phylogenetic analysis was performed using NS5B sequences amplified from seroconverters. During a total followup duration of 4,270 person-years (PY), 30 patients (3.36%) had HCV seroconversion, with an overall incidence rate of 7.03 per 1,000 PY. The rate increased from 0 in 1994 to 2000 and 2.29 in 2001 to 2005 to 10.13 per 1,000 PY in 2006 to 2010 (P < 0.05). After adjustment for age and HIV transmission route, recent syphilis remained an independent factor associated with HCV seroconversion (odds ratio, 7.731; 95% confidence interval, 3.131 to 19.086; P < 0.01). In a nested case-control study, seroconverters had higher aminotranferase levels and were more likely to have CD4 ≥ 200 cells/µl and recent syphilis than nonseroconverters (P < 0.05). Among the 21 patients with HCV viremia, phylogenetic analysis revealed 7 HCV transmission clusters or pairs (4 within genotype 1b, 2 within genotype 2a, and 1 within genotype 3a). The incidence of HCV seroconversion that is associated with recent syphilis is increasing among HIV-infected patients in Taiwan.

Metabolic syndrome among HIV-infected Taiwanese patients in the era of highly active antiretroviral therapy: prevalence and associated factors.

OBJECTIVES: Metabolic complications related to antiretroviral therapy are rarely investigated among HIV-infected patients in Asian countries. We investigated the prevalence of and factors associated with metabolic syndrome among HIV-infected patients who are ethnic Chinese in the era of highly active antiretroviral therapy (HAART). METHODS: A cross-sectional survey was performed to collect information on the demographic and clinical characteristics and antiretroviral therapy prescribed in 877 HIV-infected patients at a university hospital in Taiwan from May 2008 to April 2009. The modified Adult Treatment Panel III criteria were used to define metabolic syndrome after adjusting for the waist circumference criteria for Asians. RESULTS: Of the 877 patients, 75.3% were male homosexuals, 80.7% were receiving HAART and 88.7% had CD4 counts ≥ 200 cells/mm(3). Metabolic syndrome was diagnosed in 210 patients (26.2%). After adjusting for age, gender, smoking status, family history of diabetes mellitus, cardiovascular disease and hypertension, and baseline CD4 and plasma HIV RNA load, use of protease inhibitors (PIs) was significantly associated with the presence of metabolic syndrome (OR 1.63; 95% CI 1.10-2.43). In addition, exposure to PI for ≥ 3 years, to HAART for ≥ 6 years and to nucleoside reverse transcriptase inhibitor(s) for ≥ 6 years was significantly associated with the presence of metabolic syndrome with an adjusted OR of 1.96 (95% CI 1.13-3.42), 1.78 (95% CI 1.03-3.07), and 1.91 (95% CI 1.11-3.30), respectively. CONCLUSIONS: Approximately one-fourth of HIV-infected Taiwanese patients developed metabolic syndrome in the HAART era. Receipt of HAART and prolonged exposure to PI and nucleoside reverse transcriptase inhibitor(s) were associated with metabolic syndrome.

Microbiological and clinical characteristics of vancomycin-resistant Enterococcus faecium bacteraemia in Taiwan: implication of sequence type for prognosis.

OBJECTIVES: Vancomycin-resistant enterococci (VRE), particularly vancomycin-resistant Enterococcus faecium (VREfm), have emerged among the leading pathogens causing hospital-acquired infections worldwide. We aimed to examine whether there were newly introduced clones contributing to this increase and to assess the risk factors for mortality in patients with VREfm bacteraemia. METHODS: Between 2003 and 2010, all medical records of adult patients diagnosed with VREfm bacteraemia at a university hospital in Taiwan were reviewed. Antibiotic susceptibility, genotyping and multilocus sequence typing of the VREfm isolates were performed. RESULTS: During the study period, the prevalence of non-duplicated blood VRE isolates increased significantly from 3.9% in 2003 to 18.9% in 2010 (P < 0.0001). One-hundred-and-forty-nine patients with VREfm bacteraemia were noted and 102 isolates of VREfm were available for microbiological characterization. All isolates were susceptible to daptomycin and linezolid. Sequence type (ST) 18 and ST414 were the two predominant emerging STs from 2009 to 2010, accounting for 29.7% and 25.0% of all isolates, respectively. Patients who received immunosuppressives, had a high Charlson comorbidity index or experienced septic shock had a significantly higher 14 day mortality rate. Patients who had bacteraemia caused by ST414 isolates and received appropriate antibiotics had a lower 14 day mortality rate. CONCLUSIONS: The prevalence of the VRE that caused bacteraemia increased from 2003 to 2010. This increase might be attributed to the clonal spread of VREfm belonging to ST18 and ST414. The all-cause 14 day mortality rate was lower in patients with bacteraemia due to VREfm isolates that belonged to ST414.

Trends of transmitted drug resistance of HIV-1 and its impact on treatment response to first-line antiretroviral therapy in Taiwan.

OBJECTIVES: To determine the impact of transmitted drug resistance (TDR) of HIV-1 on treatment outcome in areas where routine testing for drug resistance mutations may not be available before combination antiretroviral therapy (cART) is initiated. METHODS: Genotypic resistance assays were performed on HIV isolates from archived blood samples obtained from 1349 antiretroviral-naive HIV-1-infected patients in Taiwan from 2000 to 2010. Resistance mutations were interpreted with the use of the HIVdb program of the Stanford University HIV Drug Resistance Database. The genotypic sensitivity score (GSS) of the regimens prescribed was calculated. A matched case-control study was conducted to assess the impact of TDR on treatment outcomes. RESULTS: The overall prevalence of TDR to any antiretroviral agent was 8.0%, declining from 12.3% in 2003-06 to 5.1% in 2007-10. In the matched case-control study, 31 patients with high- or intermediate-level resistance, 16 with low-level resistance and 89 controls were enrolled. Compared with regimens with GSS >2.5, initiation of regimens with GSS ≤2.5 was associated with a higher treatment failure rate (39.3% versus 15.7%, P = 0.02) and shorter time to treatment failure (log-rank P < 0.001). In patients receiving regimens with GSS ≤2.5, protease inhibitor-based regimens were less likely to result in treatment failure, compared with non-nucleoside reverse-transcriptase inhibitor-based regimens (hazard ratio 0.26, 95% CI 0.06-1.12, P = 0.07). CONCLUSIONS: In Taiwan the prevalence of TDR of HIV-1 strains declined and stabilized between 2007 and 2010. Receipt of antiretroviral regimens with GSS ≤2.5 was associated with poorer treatment responses than regimens with GSS >2.5.

Seroprevalence of hepatitis virus infection in men who have sex with men aged 18-40 years in Taiwan.

BACKGROUND/PURPOSE: Men who have sex with men (MSM) are at increased risk for hepatitis A virus (HAV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections than the general population. Comparisons of the seroprevalence rates of these hepatitis viruses between HIV-positive and HIV-negative MSM are rarely performed in Taiwan. METHODS: Between January 2009 and June 2010, data on the serologies for HAV, HBV, and HCV were collected from two groups of patients: HIV-negative MSM, aged 18-40 years, who sought voluntary counseling and testing (VCT) for HIV infection, and HIV-positive MSM of the same age group who sought HIV care at the National Taiwan University Hospital. Both groups of patients were also tested for syphilis. RESULTS: During the 18-month study period, 690 HIV-negative MSM and 438 HIV-positive MSM were enrolled and tested for anti-HAV antibody, HBV surface antigen (HBsAg), hepatitis B core antibody (anti-HBc antibody), and anti-HCV antibody. HIV-positive MSM were older than HIV-negative MSM (30.5 ± 5.4 vs. 25.8 ± 4.7 years, p < 0.01). For HIV-positive MSM, the mean CD4 lymphocyte count was 477.6 ± 230.0 cells/µL and 46% of them had undetectable plasma HIV RNA load (< 40 copies/mL by reverse transcription-polymerase chain reaction assay). The overall seroprevalence rates of HAV, HBsAg, and HCV in HIV-positive MSM were 15.1%, 16.4%, and 5.5%, respectively, while in HIV-negative MSM, they were 7.4%, 6.2%, and 0.4%, respectively. In the multivariate analysis, age was significantly associated with seropositivity for HAV (OR [per one age group increase]: 1.96; 95% CI: 1.6-2.5), HBsAg (OR: 2.02; 95% CI: 1.6-2.6), anti-HBc (OR: 2.68; 95% CI: 2.3-3.2), anti-HCV (OR: 1.67; 95% CI: 1.0-2.7), and anti-HBs (OR: 1.25; 95% CI: 1.0-1.5). HIV infection was associated with seropositivity for HBsAg (OR: 1.73; 95% CI: 1.1-2.7), anti-HBc (OR: 2.44; 95% CI: 1.8-3.3), HCV (OR: 8.91; 95% CI: 2.5-31.4), and syphilis (OR: 11.21; 95% CI: 6.7-18.9). CONCLUSION: HIV-positive MSM have a higher seroprevalence rate of HBV and HCV infection than HIV-negative MSM in Taiwan. Vaccination and safe-sex counseling should be provided to prevent the transmission of hepatitis viruses among MSM who may be engaged in high-risk behaviors.

Impact of vaccination with seven-valent pneumococcal conjugate vaccine on virologic and immunologic outcomes among HIV-infected adult patients in the era of highly active antiretroviral therapy.

BACKGROUND/PURPOSE: Pneumococcal polysaccharide vaccination may be associated with adverse outcomes in HIV-infected individuals who did not receive highly active antiretroviral therapy (HAART). Our aim was to evaluate the impact of vaccination with seven-valent pneumococcal conjugate vaccine (PCV) on the short-term clinical, virologic, and immunologic outcomes among HIV-infected adult patients in the HAART era. METHODS: A total of 429 HIV-infected adult patients were enrolled from October 2008 to March 2010: 213 received two doses of seven-valent PCV given at a 4-week interval and 216 received one dose. All patients were given 1-week diary to record any discomfort after vaccination. Data of serial CD4 and plasma HIV RNA load measurements were recorded. RESULTS: Of the 429 patients with a mean CD4 count of 305 cells/µL, 289 (67.4%) were receiving HAART and 175 (40.8%) had plasma HIV RNA load <40 copies/mL at vaccination. Of the 396 patients (92.3%) who returned the diary, injection site soreness (24.0%) and pain (10.4%) were the most commonly reported adverse effects. After 3-4 months of vaccination, CD4 count increased by 40 cells/µL in 278 patients (68.2%) who continued HAART, compared with a decrease of 38 cells/µL in 131 patients (31.8%) who were not on HAART (p < 0.001), while the respective change in plasma HIV RNA load was 0.8 versus 0.2 log(10) copies/mL (p = 0.09). One patient died, two developed opportunistic infections, and one developed pneumococcal pneumonia following vaccination. CONCLUSION: Vaccination with seven-valent PCV among HIV-infected patients is generally safe, which has no detrimental effect on CD4 count and plasma HIV RNA load in patients receiving HAART. (ClinicalTrials.gov number, NCT00885628).

Antimicrobial susceptibilities of commonly encountered bacterial isolates to fosfomycin determined by agar dilution and disk diffusion methods.

We studied the antimicrobial activity of fosfomycin against 960 strains of commonly encountered bacteria associated with urinary tract infection using standard agar dilution and disk diffusion methods. Species studied included 3 common species of Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia; methicillin-susceptible and -resistant Staphylococcus aureus; and vancomycin-susceptible and resistant Enterococcus faecalis and E. faecium. MICs and inhibition zone diameters were interpreted in accordance with both the currently recommended Clinical and Laboratory Standards Institute (CLSI) criteria for urinary tract isolates of Escherichia coli and Enterococcus faecalis and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria for Enterobacteriaceae. Tentative zone diameter interpretive criteria were developed for species not currently published by CLSI or EUCAST. Escherichia coli was uniformly susceptible to fosfomycin, as were most strains of Klebsiella pneumoniae and Enterobacter cloacae. A. baumannii was resistant to fosfomycin, while the prevalence of resistance in P. aeruginosa and S. maltophilia was greatly affected by the choice of MIC breakpoint. New tentative zone diameter criteria for K. pneumoniae, E. cloacae, S. aureus, and E. faecium were able to be set, providing some interim laboratory guidance for disk diffusion until further breakpoint evaluations are undertaken by CLSI and EUCAST.

Correlation between antibiotic consumption and resistance of Gram-negative bacteria causing healthcare-associated infections at a university hospital in Taiwan from 2000 to 2009.

OBJECTIVES: This study investigated the correlation between antibiotic consumption and antimicrobial resistance in Gram-negative bacteria causing healthcare-associated infections at a university hospital in Taiwan from 2000 to 2009. METHODS: Disc susceptibility data of Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens, Proteus spp., Pseudomonas aeruginosa, Acinetobacter spp., Stenotrophomonas maltophilia and other non-fermentative Gram-negative bacilli causing healthcare-associated infections were evaluated. Data on annual patient-days and annual consumption (defined daily doses per 1000 patient-days) of extended-spectrum cephalosporins, ß-lactam/ß-lactamase inhibitor combinations, carbapenems, aminoglycosides and fluoroquinolones were analysed. RESULTS: The trend of total consumption of extended-spectrum cephalosporins, ß-lactam/ß-lactamase inhibitor combinations, carbapenems, aminoglycosides and fluoroquinolones significantly increased between 2000 and 2003 and remained stable between 2004 and 2009. The decreasing use of gentamicin and amikacin in recent years was associated with increasing susceptibility of E. coli, E. cloacae, S. marcescens and P. aeruginosa to gentamicin, as well as increasing susceptibility of P. aeruginosa to amikacin. The use of piperacillin/tazobactam was positively correlated with the prevalence of piperacillin/tazobactam-resistant E. coli and S. maltophilia. In contrast, the use of cefotaxime and piperacillin/tazobactam was negatively correlated with the prevalence of cefotaxime-resistant E. coli and piperacillin/tazobactam-resistant S. maltophilia, respectively. The consumption of fluoroquinolones was positively correlated with the rates of ciprofloxacin-resistant E. coli, piperacillin/tazobactam-resistant P. aeruginosa and ceftazidime-resistant S. maltophilia. CONCLUSIONS: The relationship between antibiotic prescription and the rates of resistance for Gram-negative bacteria is complicated; every type of antimicrobial agent or even individual agent can have distinct associations with different pathogens.

Combination anti-HIV-1 antibody therapy is associated with increased virus-specific T cell immunity.

Combination antiretroviral therapy (ART) is highly effective in controlling human immunodeficiency virus (HIV)-1 but requires lifelong medication due to the existence of a latent viral reservoir1,2. Potent broadly neutralizing antibodies (bNAbs) represent a potential alternative or adjuvant to ART. In addition to suppressing viremia, bNAbs may have T cell immunomodulatory effects as seen for other forms of immunotherapy3. However, this has not been established in individuals who are infected with HIV-1. Here, we document increased HIV-1 Gag-specific CD8+ T cell responses in the peripheral blood of all nine study participants who were infected with HIV-1 with suppressed blood viremia, while receiving bNAb therapy during ART interruption4. Increased CD4+ T cell responses were detected in eight individuals. The increased T cell responses were due both to newly detectable reactivity to HIV-1 Gag epitopes and the expansion of pre-existing measurable responses. These data demonstrate that bNAb therapy during ART interruption is associated with enhanced HIV-1-specific T cell responses. Whether these augmented T cell responses can contribute to bNAb-mediated viral control remains to be determined.

Combination of quadruplex qPCR and next-generation sequencing for qualitative and quantitative analysis of the HIV-1 latent reservoir.

HIV-1 infection requires lifelong therapy with antiretroviral drugs due to the existence of a latent reservoir of transcriptionally inactive integrated proviruses. The goal of HIV-1 cure research is to eliminate or functionally silence this reservoir. To this end, there are numerous ongoing studies to evaluate immunological approaches, including monoclonal antibody therapies. Evaluating the results of these studies requires sensitive and specific measures of the reservoir. Here, we describe a relatively high-throughput combined quantitative PCR (qPCR) and next-generation sequencing method. Four different qPCR probes covering the packaging signal (PS), group-specific antigen (gag), polymerase (pol), and envelope (env) are combined in a single multiplex reaction to detect the HIV-1 genome in limiting dilution samples followed by sequence verification of individual reactions that are positive for combinations of any two of the four probes (Q4PCR). This sensitive and specific approach allows for an unbiased characterization of the HIV-1 latent reservoir.

Relationship between latent and rebound viruses in a clinical trial of anti-HIV-1 antibody 3BNC117.

A clinical trial was performed to evaluate 3BNC117, a potent anti-HIV-1 antibody, in infected individuals during suppressive antiretroviral therapy and subsequent analytical treatment interruption (ATI). The circulating reservoir was evaluated by quantitative and qualitative viral outgrowth assay (Q2VOA) at entry and after 6 mo. There were no significant quantitative changes in the size of the reservoir before ATI, and the composition of circulating reservoir clones varied in a manner that did not correlate with 3BNC117 sensitivity. 3BNC117 binding site amino acid variants found in rebound viruses preexisted in the latent reservoir. However, only 3 of 217 rebound viruses were identical to 868 latent viruses isolated by Q2VOA and near full-length sequencing. Instead, 63% of the rebound viruses appeared to be recombinants, even in individuals with 3BNC117-resistant reservoir viruses. In conclusion, viruses emerging during ATI in individuals treated with 3BNC117 are not the dominant species found in the circulating latent reservoir, but frequently appear to represent recombinants of latent viruses.