Search

The rebound-competent viral reservoir (RCVR), comprised of virus that is able to persist during antiretroviral therapy (ART) and mediate reactivation of systemic viral replication and rebound viremia after antiretroviral therapy interruption (ATI), remains the biggest obstacle to the eradication of HIV infection. A better understanding of the cellular and tissue origins and the dynamics of viral populations that initiate rebound upon ATI could help develop targeted therapeutic strategies for reducing the RCVR. In this study, barcoded SIVmac239M was used to infect rhesus macaques to enable monitoring of viral barcode clonotypes contributing to virus detectable in plasma after ATI. Blood, lymphoid tissues (LTs, spleen, mesenteric and inguinal lymph nodes), and non-lymphoid tissues (NLTs, colon, ileum, lung, liver, and brain) were analyzed using viral barcode sequencing, intact proviral DNA assay, single-cell RNA sequencing, and combined CODEX/RNAscope/ in situ hybridization. Four of seven animals had viral barcodes detectable by deep sequencing of plasma at necropsy although plasma viral RNA remained < 22 copies/mL. Among the tissues studied, mesenteric and inguinal lymph nodes, and spleen contained viral barcodes detected in plasma, and trended to have higher cell-associated viral loads, higher intact provirus levels, and greater diversity of viral barcodes. CD4+ T cells were the main cell type harboring viral RNA (vRNA) after ATI. Further, T cell zones in LTs showed higher vRNA levels than B cell zones for most animals. These findings are consistent with LTs contributing to virus present in plasma early after ATI. ONE SENTENCE SUMMARY: The reemerging of SIV clonotypes at early post-ATI are likely from the secondary lymphoid tissues.

The gut is a major reservoir in HIV-infected individuals on antiretroviral therapy (ART) and in long-term non-progressors (LTNPs). Whether ART reduces gut infection and reservoirs in LTNPs is unknown. Herein, SIV-infected LTNP Rhesus macaques were treated with short- or long-term ART, and SIV envelope gp120 sequences obtained from single genome amplification were analyzed before and after ART in peripheral blood and the intestine. Although ART does not eliminate SIV in these LTNPs, a longer ART period dramatically reduces SIV infection in the gut. This study highlights the importance of long-term ART in LTNPs to minimize gut infection and prolong remission.

Context.— Emerging evidence shows correlation between the presence of neutralization antibodies (nAbs) and protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently available commercial serology assays lack the ability to specifically identify nAbs. An enzyme-linked immunosorbent assay–based nAb assay (GenScript cPass neutralization antibody assay) has recently received emergency use authorization from the Food and Drug Administration. Objective.— To evaluate the performance characteristics of this assay and compare and correlate it with the commercial assays that detect SARS-CoV-2–specific immunoglobulin G (IgG). Design.— Specimens from SARS-COV-2 infected patients (n = 124), healthy donors obtained prepandemic (n = 100), and patients with non–coronavirus disease 2019 (COVID-19) respiratory infections (n = 92) were analyzed using this assay. Samples with residual volume were also tested on 3 commercial serology platforms (Abbott, Euroimmun, Siemens). Twenty-eight randomly selected specimens from patients with COVID-19 and 10 healthy controls were subjected to a plaque reduction neutralization test. Results.— The cPass assay exhibited 96.1% (95% CI, 94.9%–97.3%) sensitivity (at >14 days post–positive PCR), 100% (95% CI, 98.0%–100.0%) specificity, and zero cross-reactivity for the presence of non–COVID-19 respiratory infections. When compared with the plaque reduction assay, 97.4% (95% CI, 96.2%–98.5%) qualitative agreement and a positive correlation (R2 = 0.76) was observed. Comparison of IgG signals from each of the commercial assays with the nAb results from plaque reduction neutralization test/cPass assays displayed greater than 94.7% qualitative agreement and correlations with R2 = 0.43/0.68 (Abbott), R2 = 0.57/0.85 (Euroimmun), and R2 = 0.39/0.63 (Siemens), respectively. Conclusions.— The combined data support the use of cPass assay for accurate detection of the nAb response. Positive IgG results from commercial assays associated reasonably with nAbs presence and can serve as a substitute.

Background Chikungunya virus (CHIKV) is a mosquito-borne pathogen, within the Alphavirus genus of the Togaviridae family, that causes ~1.1 million human infections annually. CHIKV uses Aedes albopictus and Aedes aegypti mosquitoes as insect vectors. Human infections can develop arthralgia and myalgia, which results in debilitating pain for weeks, months, and even years after acute infection. No therapeutic treatments or vaccines currently exist for many alphaviruses, including CHIKV. Targeting the phagocytosis of CHIKV by macrophages after mosquito transmission plays an important role in early productive viral infection in humans, and could reduce viral replication and/or symptoms. Methods To better characterize the transcriptional response of macrophages during early infection, we generated RNA-sequencing data from a CHIKV-infected human macrophage cell line at eight or 24 hours post-infection (hpi), together with mock-infected controls. We then calculated differential gene expression, enriched functional annotations, modulated intracellular signaling pathways, and predicted therapeutic drugs from these sequencing data. Results We observed 234 pathways were significantly affected 24 hpi, resulting in six potential pharmaceutical treatments to modulate the affected pathways. A subset of significant pathways at 24 hpi includes AGE-RAGE, Fc epsilon RI, Chronic myeloid leukemia, Fc gamma R-mediated phagocytosis, and Ras signaling. We found that the MAPK1 and MAPK3 proteins are shared among this subset of pathways and that Telmisartan and Dasatinib are strong candidates for repurposed small molecule therapeutics that target human processes. The results of our analysis can be further characterized in the wet lab to contribute to the development of host-based prophylactics and therapeutics.

Summary Background SARS-CoV-2 is the virus responsible for the current global pandemic, COVID-19. Because this virus is novel, little is known about its sensitivity to disinfection. Methods We performed suspension tests against SARS-CoV-2 using three commercially available quaternary ammonium compound (Quat) disinfectants and one laboratory-made 0.2% benzalkonium chloride solution. Findings Three of the four formulations completely inactivated the virus within 15 s of contact, even in the presence of a soil load or when diluted in hard water. Conclusion Quats rapidly inactivate SARS-CoV-2, making them potentially useful for controlling SARS-CoV-2 spread in hospitals and the community.

Chronic immune inflammation (CII) is a characteristic symptom of HIV-1 infection that contributes to acquired immunodeficiency syndrome (AIDS) progression in infected patients. Distinct AIDS development rates have shown that there are Rapid Progressor (RP) and Long-Term Non-Progressor (LTNP) patients, but the circumstances governing these differences in disease progression are poorly understood. Mutations in the Viral Protein R (Vpr) have been suggested to have a direct impact on disease progression. Studies have shown that Vpr interacts with both host and viral factors; these interactions affect cellular activities such as cell cycle progression and enhancement of apoptosis. The Vpr mutants R36W and R77Q have been associated with RP and LTNP phenotypes, respectively; however, these findings are still controversial. This study sheds light on the effects that Vpr mutations have in the context of HIV-1 infection of the HUT78 T cell line, using replication-competent CXCR4-tropic virus strains. Our results show a replication enhancement of the R36W mutant (increased viral load and percentage of p24+ cells) accompanied by increased cytotoxicity. Interestingly, the R77Q mutant showed a unique enhancement of apoptosis (measured by Annexin V and TUNEL staining) and G2 cell cycle arrest; these effects were not seen with WT or R36W viruses. Since necrosis is associated with the release of pro-inflammatory factors, the R36 mutation could lead to more robust CII and the RP phenotype. Conversely, the R77Q mutation leads to apoptosis, potentially avoiding CII and leading to a LTNP phenotype. Thus, Vpr mutations may impact HIV-1 related progression to AIDS. Importance The vpr gene is thought to be an important virulence factor in Human Immunodeficiency Virus type 1 (HIV-1). vpr polymorphisms have been associated with different rates of acquired immunodeficiency syndrome (AIDS) progression. However, there is controversy about the cytopathic and virulence phenotypes of Vpr mutants, with contradictory conclusions about the same mutants. Here, we examine the replication capacity, apoptosis induction, and G2 cell cycle arrest phenotypes of three vpr mutants compared to wild-type HIV-1. One mutant associated with rapid AIDS progression replicated more efficiently and killed cells more rapidly than wild-type HIV-1. Another mutant associated with slow AIDS progression triggered apoptosis more efficiently than wild-type HIV-1. These results shed additional light on the role of vpr polymorphisms in T cell killing by HIV-1 and may help to explain the role of Vpr in different rates of AIDS progression.

Transcription activator-like effector nucleases (TALENs) are one of several types of programmable, engineered nucleases that bind and cleave specific DNA sequences. Cellular machinery repairs the cleaved DNA by introducing indels. In this review, we emphasize the potential, explore progress, and identify challenges in using TALENs as a therapeutic tool to treat HIV infection. TALENs have less off-target editing and can be more effective at tolerating HIV escape mutations than CRISPR/Cas-9. Scientists have explored TALEN-mediated editing of host genes such as viral entry receptors (CCR5 and CXCR4) and a protein involved in proviral integration (LEDGF/p75). Viral targets include the proviral DNA, particularly focused on the long terminal repeats. Major challenges with translating gene therapy from bench to bedside are improving cleavage efficiency and delivery, while minimizing off-target editing, cytotoxicity, and immunogenicity. However, rapid improvements in TALEN technology are enhancing cleavage efficiency and specificity. Therapeutic testing in animal models of HIV infection will help determine whether TALENs are a viable HIV treatment therapy. TALENs or other engineered nucleases could shift the therapeutic paradigm from life-long antiretroviral therapy toward eradication of HIV infection.