HIV-1 P24 Research Articles

Flavonol 7-O-Glucoside Herbacitrin Inhibits HIV-1 Replication through Simultaneous Integrase and Reverse Transcriptase Inhibition.

Here we report the evaluation of the antiretroviral effect of two flavonoid 7-O-glucosides, herbacitrin (1) and gossypitrin (2), together with quercetin (3), a well-studied flavonol. Antiviral activity of the flavonoids was assessed by analyzing HIV-1 p24 core protein levels in the supernatants of HIV-1 infected MT-4 and MT-2 cell cultures. The compounds showed mild to weak cytotoxic activities on the host cells; herbacitrin was the strongest in this regard (CC50=27.8 and 63.64 μM on MT-4 and MT-2 cells, respectively). In nontoxic concentrations, herbacitrin and quercetin reduced HIV-1 replication, whereas gossypitrin was ineffective. Herbacitrin was found to inhibit reverse transcriptase at 21.5 μM, while it was a more potent integrase inhibitor already active at 2.15 μM. Therefore, our observations suggest that herbacitrin exerts antiretroviral activity through simultaneously acting on these two targets of HIV-1 and that integrase inhibition might play a major role in this activity.

Immunoassay Detection using Direct Single-Molecule Counting

Single-molecule methods have a great deal of specificity for studying complex systems and dynamics, but they also offer high sensitivity for basic enumeration. We apply single-molecule TIRF to immunoassays by simply and literally counting the number of target molecules captured on a streptavidin surface. We demonstrate that utility of using single-molecule counting on eluted detection conjugate, the capture and sandwich formation portions of the assay having completed on microparticles or other systems. This approach is simple and effective, and creates the opportunity for a universal detection platform that can be used to perform a variety of assays. We take advantage of the low volume requirements of single-molecule detection and apply a sample reloading approach to concentrate sample onto the detection surface. Due to the high affinity of the streptavidin-biotin reaction, concentration through reloading is both quick and robust. These findings are demonstrated on both model and HIV p24 antigen assay systems. Single-molecule detection techniques do not need to be complex to exhibit both power and flexibility, and so can become valuable in the field of immunoassay diagnostics.

Cross-Subtype Detection of HIV-1 Capsid p24 Antigen Using a Sensitive Europium Nanoparticle Assay.

Accurate and early detection of diverse HIV-1 subtypes using currently available p24 antigen assays have been a major challenge. We report the development of a sensitive time resolved fluorescence (TRF) europium nanoparticle immuno assay for cross subtype detection of p24 antigen using broadly cross-reactive antibodies. Several antibodies were tested for optimal reactivity with antigens of diverse HIV-1 subtypes and circulating recombinant forms. We tested HIV strains using this assay for sensitivity and quantification ability at the pico-gram per millilter level. We identified two broadly cross-reactive HIV-1 p24 antibodies C65690M and ANT-152, which detected all strains of HIV tested. These two antibodies also yielded a better signal to cutoff ratio for the same amount of antigen tested in comparison to a commercial assay. Using an appropriate combination of C65690M and ANT-152 p24 antibodies capable of detecting all HIV types and highly sensitive TRF-based europium nano particle assay platform, we developed a sensitive p24 antigen assay that can detect HIV infection of all HIV subtypes and may be useful in early detection.

Possible immunochemical pattern of Anti-HCV, HBeAg, HBsAg HBeAb, and HIV-1 p24 in newly infected Mycobacterium pulmonary tuberculosis patients

Background: Viral biomarkers in pulmonary tuberculosis (PTB) could be a primary or secondary viral infection to PTB which may depressed immunity or make the patient susceptible to the secondary infection. Aim and Objective: This work was, therefore, designed to determine frequency of anti-hepatitis C virus (HCV), hepatitis B envelope antigen (HBeAg), hepatitis B surface antigen (HBsAg), hepatitis B envelope antibody (HBeAb), and human immunodeficiency virus (HIV)-1 p24 in newly infected Mycobacterium PTB patients. Materials and Methods: Sixty newly infected Mycobacterium tuberculosis patients were recruited from the medical outpatient Department of Baptist Medical center, Saki-Nigeria. The patients were classified into females (30) and males (30) aged 38–79 years. M. tuberculosis was determined in the patients through fluorescence immunoassay, cultivation of sputum sample on Lowentein–Jensen medium, and radiological chest X-ray report. Anti-HCV, HBeAg, HBsAg HBeAb, and HIV-1 p24 were determined in the patients by immunochromatography and ELISA methods. Results: The viral immunochemical pattern obtained in the newly infected PTB patients showed a frequency of: 5% (3) (males - 3.3% [2] and females - 1.67% [1]) anti-HCV; 3.3% (2) (all males - 3.3% [2]) HIV-1 - p24; 15% (9) (males - 3 [5%] and females - 6 [10%]) HBsAg; 9 (15%) (males - 5% [3] and females - 10% [6]) HBeAg; 18.33% (11) (males - 6.7% [4] and females - 11.67% [7]) hepatitis B envelope (HBe) antibody; 3.33% (2) (males - 1.67%[1] and females - 1.67% [1]) HBeAg + HBsAg + HIV-1 - p24. Conclusion: This work revealed evidence of anti-HCV; HIV-1 - p24; HBsAg; HBeAg; and HBe antibody and HBeAg + HBsAg + HIV-1 - p24 in newly infected pulmonary M. tuberculosis-infected patients. Routine evaluation of viral biomarkers in PTB patients is necessary for effective management.

Possible Immunological Alterations in the Plasma Levels of TNF-α and IL-10 in the Traditional Application of Vernonia Amygdalina (Ewuro) Leaves in the Treatment of Diabetes Mellitus

Diabetes mellitus can induce release of free radicals and oxidative stress, which can trigger production of cytokines. Vernonia amygdalina has antidiabetic activity due to its phytochemical constituents. This work was designed to determine possible immunological alterations in the plasma levels of TNF-α and Interleukin-10 (IL-10) in the traditional application of V. amygdalina (Ewuro) leaves in the treatment of diabetes mellitus. The study populations include all 33 diabetes mellitus patients (51-67 years; male, 21; female, 12) who had not commenced any form of medication or treatment and received herbal treatment in 10 herbal homes of Saki West, a local government area in Nigeria. Twenty-seven agematched volunteers who were treated on insulin medication in the hospital almost within the same period were also investigated. Patients who were positive to acid-fast bacilli sputum test, Plasmodium spp., identification, HBsAg, anti-HCV, and HIV-1 p24 assays were not included. Plasma TNF-α, IL-10, HBsAg, anti-HCV, and HIV-1 p24 were determined in the patients by ELISA while identification of acid-fast bacilli and Plasmodium spp. were carried out by Ziehl-Neelsen and Giemsa thick blood-film staining, respectively. There was a significant decrease in the plasma levels of TNF-α, IL-10, and glucose in diabetes mellitus patients after the administration of raw liquid extract of V. amygdalina and insulin compared to their basal samples before the commencement of the treatment (p < 0.05). The work revealed a significant increase in plasma TNF-α, IL-10, and glucose in diabetes patients, which returned to normal plasma values after treatment using raw liquid extract of V. amygdalina leaves and insulin.

Clinical Application Evaluation of a Fourth-Generation HIV Antigen Antibody Combination Screening Assay.

Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) are infectious diseases with high mortality. Early diagnosis is crucial. Combining HIV antibody and p24 antigen, the Elecsys HIV combi PT assay is a fourth generation HIV screening assay. The sensitivity and specificity of this assay was examined. A total of 111,556 samples was conducted from January 1, 2016, to June 30, 2018 in Zhongshan Hospital of Yat-Sen University. We conducted a fourth-generation HIV test of retrospective HIV screening samples and assessed the reliability of using signal-to-cutoff (S/CO) ratios to distinguish false positive HIV antibody reactions and analyzed false positives. A total of 122 specimens were confirmed as HIV-1 infected by western blot (WB) and HIV nucleic acid assays. The median S/CO ratio for HIV false positive specimens was 3.27, while for the HIV-infected specimen it was 391.7. Receiver operating characteristic (ROC) analysis showed that the best diagnostic point for HIV was 22.85 S/CO. The sensitivity, specificity, and Youden index were 100%, 97.8%, and 0.978, respectively. The highest false positive rate of 26.4% was found in patients with malignant tumors and blood diseases. The results of this study show that the fourth-generation Elecsys HIV combination PT test can identify early HIV infected and can be a useful adjunct to help clinicians to manage the disease by viral load testing and starting an appropriate therapy. Our research data provides a reference for subsequent research and HIV testing in the region.

Molecular Approach for HIV-1 Replication Inhibition: Assessment of Different siRNAs Targeting Tat and Nef Genes to Effectively Suppress their Expression.

Inhibition of viral genes through siRNA seems to be promising for treatment of complicated viral infections like human immunodeficiency virus (HIV-1). HIV-1 Tat (Trans Activator of Transcription) and Nef (Negative regulatory Factor) proteins are very interesting targets for designing siRNAs. The effectiveness of suppressing Tat and Nef was investigated using three specific siTATs and three siNEFs. They were used to transfect the developed stable and infected Human Embryonic Kidney cells (HEK293) as an ex-vivo model. Both stable and virus infected HEK293 cells were transfected with each siTAT and siNEF. The inhibitory effect was evaluated using qRT-PCR, western blot analysis, and HIV P24 ELISA. siTAT-100, siTAT-162, and siNEF-136 and at a concentration of 100 nM/mL showed the most inhibitory effect on their target genes. Utilization of more developed molecular inhibition strategies such as RNAi or even a combination of different molecular approaches could be promising to overcome emerging HIV escape mutants.

A simple and high-throughput luciferase immunosorbent assay for both qualitative and semi-quantitative detection of anti-HIV-1 antibodies

In this study, we described an ultrasensitive and high-throughput luciferase immunosorbent assay (LISA) for qualitative and quantitative detection of anti-HIV-1 antibody. Anti-HIV antibody in serum or plasma samples was captured by protein A/G-coated microtiter plate and detected with crude cell lysates expressing Nanoluc luciferase (Nluc) enzyme fused with HIV-1 p24 or gp41 antigen without the need of protein purification. After the addition of furimazine substrate, anti-HIV antibodies were quantitatively measured as luciferase light units. LISA showed a wide linear range of detection and was about 104-fold more sensitive than ELISA. For the detection of both anti-p24 and anti-gp41, LISA showed extraordinary sensitivity (99.5% and 100%, respectively) and equivalent specificity (100%). LISA could also monitor the change in the anti-HIV-1 antibody response over time in antiretroviral therapy (ART) treated individuals, and can sufficiently distinguish between recent and long-term HIV-1 infections. Our preliminary results indicate that LISA may provide a novel universal immunoassay platform for simultaneous HIV-1 detection, quantitative measurement of anti-HIV antibodies as well as the differentiation of HIV-1 infection stages.

Co-ordinated split aptamer assembly and disassembly on Gold nanoparticle for functional detection of HIV-1 tat

Human immunodeficiency virus (HIV) is a life threatening, weakens the immune system upon infection, thus ultimately resulting in the fatal health issues. This situation necessitates the generation of different strategies for HIV detection. HIV-1 Tat, a transactivator of HIV gene expression, was chosen in this study as the target of a non-functional split aptamer. Implementation of split aptamer has been demonstrated in this work for colorimetric detection of HIV-1 Tat. An unmodified gold nanoparticle (GNP)-based colorimetric assay was used for the visible detection of the proof, displays color transitions from red to purple in relation to the dose-dependency of HIV-1 Tat against the split aptamer in ionic solutions. The visible color transition was characterized using UV–vis spectrophotometer showing spectrum shift and supported by Scanning Electron Microscopy observation. With addition of sodium chloride, the color of the solution started to change to purple and spectrum started to shift to higher wavelength due to aggregation at HIV-1 Tat concentration as low as 10 nM. Specificity test was conducted with duplexed split aptamer and HIV-1 p24 has shown slight color changes. With HIV-1 Nef, GNP solution retains the color similar to the control, which indicated the specific split aptamer interaction to HIV-1 Tat.

Blood Plasma Separation Using a Fidget-Spinner.

In this study, we present a simple, hand-powered, and electricity-free centrifuge platform based on a commercially available "fidget-spinner." The centrifugal force provided by this inexpensive and easy-to-use toy is sufficient to separate whole blood, producing a plasma yield rate and purity of 30% and 99%, respectively, separated in as little as 4-7 min. We verified the separated plasma by performing a paper-based HIV-1 p24 capsid protein enzyme-linked immunosorbent assay, which achieved a recovery rate of up to 98%, indicating the plasma features extremely low matrix interference effects. These results demonstrate the reliability of the platform for practical use, in addition to greatly reducing the overall cost and time of analysis while retaining detection precision, making it suitable for medical applications in resource-limited regions of the world.

High-performance interactive analysis of split aptamer and HIV-1 Tat on multiwall carbon nanotube-modified field-effect transistor

Interaction between split RNA aptamer and the clinically important target, HIV-1 Tat was investigated on a biosensing surface transduced by functionally choreographed multiwall carbon nanotubes (MWCNTs). Acid oxidation was performed to functionalize MWCNTs with carboxyl functional groups. X-ray photoelectron spectroscopy analysis had profound ~2.91% increment in overall oxygen group and ~1% increment was noticed with a specific carboxyl content owing to CO and OCO bonding. The interaction between split RNA aptamer and HIV-1 Tat protein was quantified by electrical measurements with the current signal (Ids) over a gate voltage (Vgs). Initially, 34.4 mV gate voltage shift was observed by the immobilization of aptamer on MWCNT. With aptamer and HIV-1 Tat interaction, the current flow was decreased with the concomitant gate voltage shift of 23.5 mV. The attainment of sensitivity with split aptamer and HIV-1 Tat interaction on the fabricated device was 600 pM. To ensure the genuine interaction of aptamer with HIV-1 Tat, other HIV-1 proteins, Nef and p24 were interacted with aptamer and they displayed the negligible interferences with gate voltage shift of 3.5 mV and 5.7 mV, which shows 4 and 2.5 folds lesser than HIV-1 Tat interaction, respectively.

1274. Universal HIV and HCV Screening in San Diego Emergency Departments: Implications for Other Settings With a High Density of Free of Charge HIV Screening Programs

BackgroundWhile HIV and HCV testing targeted to high-risk groups results in substantially higher proportions of HIV diagnoses, universal HIV and HCV screening in emergency department (ED) settings is expected to reach populations who do not perceive themselves to be at risk or are otherwise less likely to participate in HIV and HCV testing. As a consequence the CDC recommends routine HIV screening for persons 13–64 years of age, and routine HCV screening for the birth cohort (born between 1945–1965). The objective of this analysis was to evaluate the yield of universal opt-out HIV and HCV screening in the two EDs at the University of California San Diego (UCSD).MethodsIn July 2017, electronic medical record (EMR) based universal opt-out HIV screening (Architect HIV antibody [Ab]/HIV p24 antigen detection) for persons aged 13–64 years (excluding persons known HIV+ or reporteing an HIV test within the last 12 months) was implemented in our EDs. The EMR algorithm also identified HIV+ individuals who had been out of care for >12 months. In March 2018, EMR based universal HCV screening for birth cohort was added in both EDs.ResultsOver a period of 9 months 7,303 HIV tests were conducted, resulting in 24 (0.3%) new HIV diagnoses, of which 21 were successfully linked to care. In five individuals without HIV infection Architect gave a false-positive result (specificity 99.93%). In addition, the EMR algorithm identified 38 out of care HIV+ individuals of which 21 were successfully relinked to care. During the 1-month HCV birth cohort screening 963 HCV Ab tests were conducted, of which 106 (11%) resulted positive. At the time being 78 of those seropositive individuals had HCV RNA testing, of which 36 (53%) resulted positive (3.7% of all participants).ConclusionIn San Diego, a setting with a high density of free-of charge HIV screening programs, 1/300 HIV tests in the ED yielded a new HIV diagnosis and in total 21 newly diagnosed individuals were linked to care. Identification of HIV+ out of care individuals yielded in an equivalent number of individuals relinked to care. The rate of newly diagnosed HCV infections exceeded the rate of newly diagnosed HIV infections by >10-fold outlining the importance of screening for HCV in the ED.Disclosures All authors: No reported disclosures.

Direct single-molecule counting for immunoassay applications

Single-molecule methods offer specificity in studying complex systems and dynamics, but they also offer high sensitivity for basic enumeration. We apply single-molecule TIRF to immunoassays by counting the number of target molecules captured on a streptavidin surface. We demonstrate the utility of using single-molecule counting on eluted detection conjugate, following the capture and sandwich formation portions of the assay having been completed on microparticles. This approach is simple and effective, and creates the opportunity for a universal detection platform that can be used to perform a variety of diagnostic and blood screening assays. We take advantage of the low volume requirements of single-molecule detection and apply a sample reloading approach to concentrate sample onto the detection surface. Due to the high affinity of the streptavidin-biotin reaction, concentration through reloading is both quick and robust. These findings are demonstrated on a model system and in an HIV p24 antigen assay. Single-molecule detection techniques do not need to be complex to exhibit power and flexibility, and so can become valuable in the field of immunoassay diagnostics.

A multicentre evaluation of the Elecsys® HIV Duo assay

Background: Fourth generation HIV assays, which detect both HIV p24 antigen and HIV antibodies are widely used in HIV screening. The combination of markers enables the fourth generation assays to shorten the window of detection, which is important in real-world testing scenarios. The Elecsys® HIV Duo assay is a fourth generation assay, which provides an overall result based on both the detection of the p24 antigen and HIV antibodies, and lists the sub-results for the antibody and antigen units.Objectives and study design: The performance of the Elecsys® HIV Duo assay was assessed at five international centres and compared with other available fourth generation assays.Results: The specificity of the Elecsys® HIV Duo assay in 13,328 blood donor samples was 99.87% (95% confidence interval [CI] 99.80–99.93) and was 100% (95% CI 99.63–100) in 1000 routine diagnostic samples. Sensitivity was assessed in 139 seroconversion panels; the Elecsys® HIV Duo assay detected a greater number of positive samples/number of bleeds compared with other assays investigated. An individual analysis of those seroconversion panels also shows that the Elecsys® HIV Duo assay compared to other fourth generation assays detected HIV up to 2 days earlier than other assays.The Elecsys® HIV Duo assay also detected 125/130 ‘early seroconversion’ samples assessed, which was greater than the number detected with comparator fourth generation assays.Conclusion: These results indicate that the Elecsys® HIV Duo assay is appropriate for use in the diagnosis of HIV and for screening of blood donations and is sensitive for the early detection of HIV.

Self-Assembly of Antigen Proteins into Nanowires Greatly Enhances the Binding Affinity for High-Efficiency Target Capture.

High-efficiency target capture is an essential prerequisite for sensitive immunoassays. However, the current available immunoassay approaches are subject to deficient binding affinities between predator-prey molecules that greatly restrict the target capture efficiency and immunoassay sensitivity. Herein, we present a new strategy through the self-assembly of antigen proteins into nanowires to enhance the binding affinity between an antigen and antibody. Through the genetic fusion of antigen proteins (e.g., HIV p24) with the yeast amyloid protein Sup35 self-assembly domain, specific antigen nanowires (Ag nanowires) were constructed and demonstrated a remarkable enhancement in binding affinity compared with that of the monomeric antigen molecule. The Ag nanowires were further combined with magnetic beads to form a 3D magnetic probe based on a seed-induced self-assembly strategy. Taking advantage of both the strong binding affinity and the rapid magnetic separation and enrichment capacity, the specific 3D magnetic probe achieved a 100-fold improvement in detection sensitivity within a significantly shorter period of 20 min over that of the conventional enzyme-linked immunosorbent assay method.

Mesenchymal stem cells are attracted to latent HIV-1-infected cells and enable virus reactivation via a non-canonical PI3K-NF\u03baB signaling pathway

Persistence of latent HIV-1 in macrophages (MACs) and T-helper lymphocytes (THLs) remain a major therapeutic challenge. Currently available latency reversing agents (LRAs) are not very effective in vivo. Therefore, understanding of physiologic mechanisms that dictate HIV-1 latency/reactivation in reservoirs is clearly needed. Mesenchymal stromal/stem cells (MSCs) regulate the function of immune cells; however, their role in regulating virus production from latently-infected MACs & THLs is not known. We documented that exposure to MSCs or their conditioned media (MSC-CM) rapidly increased HIV-1 p24 production from the latently-infected U1 (MAC) & ACH2 (THL) cell lines. Exposure to MSCs also increased HIV-1 long terminal repeat (LTR) directed gene expression in the MAC and THL reporter lines, U937-VRX and J-Lat (9.2), respectively. MSCs exposed to CM from U1 cells (U1-CM) showed enhanced migratory ability towards latently-infected cells and retained their latency-reactivation potential. Molecular studies showed that MSC-mediated latency-reactivation was dependent upon both the phosphatidyl inositol-3-kinase (PI3K) and nuclear factor-κB (NFκB) signaling pathways. The pre-clinically tested inhibitors of PI3K (PX-866) and NFκB (CDDO-Me) suppressed MSC-mediated HIV-1 reactivation. Furthermore, coexposure to MSC-CM enhanced the latency-reactivation efficacy of the approved LRAs, vorinostat and panobinostat. Our findings on MSC-mediated latency-reactivation may provide novel strategies against persistent HIV-1 reservoirs.

Overcoming immunogenicity issues of HIV p24 antigen by the use of innovative nanostructured lipid carriers as delivery systems: evidences in mice and non-human primates

HIV is one of the deadliest pandemics of modern times, having already caused 35 million deaths around the world. Despite the huge efforts spent to develop treatments, the virus cannot yet be eradicated and continues to infect new people. Spread of the virus remains uncontrolled, thus exposing the worldwide population to HIV danger, due to the lack of efficient vaccines. The latest clinical trials describe the challenges associated with developing an effective prophylactic HIV vaccine. These immunological obstacles will only be overcome by smart and innovative solutions applied to the design of vaccine formulations. Here, we describe the use of nanostructured lipid carriers (NLC) for the delivery of p24 protein as a model HIV antigen, with the aim of increasing its immunogenicity. We have designed vaccine formulations comprising NLC grafted with p24 antigen, together with cationic NLC optimized for the delivery of immunostimulant CpG. This tailored system significantly enhanced immune responses against p24, in terms of specific antibody production and T-cell activation in mice. More importantly, the capacity of NLC to induce specific immune responses against this troublesome HIV antigen was further supported by a 7-month study on non-human primates (NHP). This work paves the way toward the development of a future HIV vaccine, which will also require the use of envelope antigens.

In Silico Design and Immunologic Evaluation of HIV-1 p24-Nef Fusion Protein to Approach a Therapeutic Vaccine Candidate.

Background: Acquired immune deficiency syndrome (HIV/AIDS) has been a major glob-al health concern for over 38 years. No safe and effective preventive or therapeutic vaccine has been developed although many products have been investigated. Computational methods have facilitated vaccine developments in recent decades. Among HIV-1 proteins, p24 and Nef are two suitable targets to provoke the cellular immune response. However, the fusion form of these two proteins has not been analyzed in silico yet.Objective: This study aimed at the evaluation of possible fusion forms of p24 and Nef in order to achieve a potential therapeutic subunit vaccine against HIV-1.Method: In this study, various computational approaches have been applied to predict the most effec-tive fusion form of p24-Nef including CTL (Cytotoxic T lymphocytes) response, immunogenicity, conservation and population coverage. Moreover, binding to MHC (Major histocompatibility com-plex) molecules was assessed in both human and BALB/c.Results: After analyzing six possible fusion protein forms using AAY linker, we came up with the most practical form of p24 from 80 to 231 and Nef from 120 to 150 regions (according to their refer-ence sequence of HXB2 strain) using an AAY linker, based on their peptides affinity to MHC mole-cules which are located in a conserved region among different virus clades. The selected fusion protein contains seventeen MHC I antigenic epitopes, among them KRWIILGLN, YKRWIILGL, DIAG-TTSTL and FPDWQNYTP are fully conserved between the virus clades. Furthermore, analyzed class I CTL epitopes showed greater affinity binding to HLA-B 57*01, HLA-B*51:01 and HLA-B 27*02 molecules. The population coverage with the rate of >70% coverage in the Persian population supports this truncated form as an appropriate candidate against HIV-I virus.Conclusion: The predicted fusion protein, p24-AAY-Nef in a truncated form with a high rate of T cell epitopes and high conservancy rate among different clades, provides a helpful model for developing a therapeutic vaccine candidate against HIV-1.

The role of CD32 during HIV-1 infection.

Persistence of latent HIV-1 in long-lived resting memory CD4+ T cells is a major barrier to curing HIV-1 infection, and thus a biomarker for latently infected cells would be of great scientific and clinical importance.1,2,3,4,5 Through an elegant discovery-based approach, Descours et al. reported that CD32a, an Fcγ receptor not normally expressed on T cells, is a potential biomarker for latently infected cells.6 Using the quantitative viral outgrowth assay, we show that CD32+ CD4+ T cells do not harbor the majority of intact proviruses in the latent reservoir and that the enrichment found by Descours et al. may in part reflect the use of an ultrasensitive ELISA for HIV-1 p24 antigen that does not predict exponential viral outgrowth. Our studies show that CD32 is not a biomarker for the major population of latently infected CD4+ T cells.

Ranpirnase Reduces HIV-1 Infection and Associated Inflammatory Changes in a Human Colorectal Explant Model.

Ranpirnase (RNP) is a low molecular weight type III endoribonuclease, which demonstrates broad antiviral and antitumor properties. We sought to characterize the antiviral activity of RNP against HIV-1 and to determine whether RNP modulates local inflammatory changes associated with HIV infection in the colorectal explant model. Colorectal explants were incubated for 2 h with HIV-1BaL, in the presence of increasing concentrations of RNP (0-60 μg/mL). After washing, explants were cultured for 14 days, with supernatant collected at days 3, 7, 10, and 14. All samples were assayed for HIV-1 p24. Additionally, 30 soluble inflammatory biomarkers were assayed in the day 3 supernatant sample. Other biopsies were stimulated with lipopolysaccharides (LPS) (10 μg/mL) in the presence of RNP and soluble biomarkers assayed at day 3. RNP inhibited productive infection of the colorectal explants with HIV-1BaL and induced a dose-dependent decrease in 15/30 biomarkers. Affected biomarkers included IP-10, MDC, MIP-1α, MIP-1β, TARC, IL12-p40, IL-15, IL-17, IL-1α, IL-7, IFNγ, IL12-p70, IL-1β, IL-4, IL-5, and TNF-β. Similarly, RNP dose-dependent inhibition was demonstrated in 7/30 biomarkers after LPS stimulation, all of which overlapped with HIV-1BaL-induced biomarker changes. The ability of RNP to inhibit both colorectal explant HIV-1BaL infection and inflammatory changes associated with HIV-1 infection makes RPN a promising agent for topical rectal pre-exposure prophylaxis.