HIV-1 controllers are patients who control HIV-1 viral replication without antiretroviral therapy. Control is achieved very early in the course of infection, but the mechanisms through which viral ...replication is restricted are not fully understood. We describe a patient who presented with acute HIV-1 infection and was found to have an HIV-1 RNA level of <100copies/mL. She did not have any known protective HLA alleles, but significant immune activation of CD8+ T cells and natural killer (NK) cells was present, and both cell types inhibited viral replication. Virus cultured from this patient replicated as well in vitro as virus isolated from her partner, a patient with AIDS who was the source of transmission. Virologic breakthrough occurred 9months after her initial presentation and was associated with an increase in CD4+ T cell activation levels and a significant decrease in NK cell inhibitory capacity. Remarkably, CD8+ T cell inhibitory capacity was preserved and there were no new escape mutations in targeted Gag epitopes. These findings suggest that fully replication-competent virus can be controlled in acute HIV-1 infection in some patients without protective HLA alleles and that NK cell responses may contribute to this early control of viral replication.
•We show that an HIV-1 controller was infected with pathogenic virus yet maintained low viral loads during primary infection.•She had activated NK cells and CD8+ T cells and both cell types suppressed HIV-1 replication shortly after infection.•She eventually lost control of viral replication, and this was associated with a reduction in NK cell suppressive activity.
HIV-1 controllers are patients who control the virus without HIV-1 medications. These patients may teach us how to design a vaccine against HIV-1. Little is known about how the virus is controlled in the early phase of infection in these patients. Here we show that a recently infected HIV-1 controller had a strong natural killer cell response to the virus. Interestingly, she lost control of the virus 9months later and her natural killer cell response to the virus was diminished. Our work suggests that natural killer cells may have contributed to viral control in the early phase of infection.
A CD3/CD28 microbead-based HIV-1 viral outgrowth assay Kuzmichev, Yury V; Veenhuis, Rebecca T; Pohlmeyer, Christopher W ...
Journal of Virus Eradication,
2017-Apr-01, 2017-04-00, 20170401, 2017-04-01, Volume:
3, Issue:
2
Journal Article
Peer reviewed
Open access
Latently infected resting CD4 T cells represent a major barrier to HIV-1 eradication efforts. The standard assays used for measuring this reservoir induce activation of resting CD4 T cells with ...either phytohaemagglutinin (PHA) with irradiated feeder cells, or with anti-CD3 antibodies. We designed a study to compare the sensitivity of a new assay (based on the stimulation of CD4 T cells with anti-CD3 and anti-CD28 coated microbeads) with that of the traditional PHA- and feeder-based viral outgrowth assay.
Resting CD4 T cells from 10 HIV-1-infected patients on suppressive combination antiretroviral therapy (cART) regimens were cultured in the traditional PHA/feeders viral outgrowth assay and the new CD3/CD28 bead-based assay. Flow cytometry was used to assess the kinetics of activation of resting CD4 T cells in the two different assays.
There was no significant difference in the sensitivity of the two assays. The median frequency of latently infected cells was 0.83 infectious units per million (IUPM) for the PHA/feeders assay and 0.54 IUPM with the CD3/CD28 bead-based assay. However, while virus was obtained from all 10 patients with the traditional PHA/feeders outgrowth assay, no virus was obtained from two of 10 patients with the novel anti-CD3/CD28 bead-based viral outgrowth assay (IUPM < 0.02).
The new CD3/CD28 bead-based assay has comparable sensitivity to the PHA/feeders assay and does not require the addition of feeders, making it a simpler and less labour-intensive alternative to the standard PHA/feeders-based assay.
Abstract
The Coronavirus Disease 2019 (COVID-19) pandemic has fueled unprecedented development of animal models to understand disease pathogenesis, test therapeutics, and support vaccine development. ...Models previously developed to study severe acute respiratory syndrome coronavirus (SARS-CoV) have been rapidly deployed to study SARS-CoV-2. However, it has become clear that despite the common use of ACE2 as a receptor for both viruses, the host range of the 2 viruses does not entirely overlap. Distinct ACE2-interacting residues within the receptor binding domain of SARS-CoV and SARS-CoV-2, as well as species differences in additional proteases needed for activation and internalization of the virus, are likely sources of host differences between the 2 viruses. Spontaneous models include rhesus and cynomolgus macaques, African Green monkeys, hamsters, and ferrets. Viral shedding and transmission studies are more frequently reported in spontaneous models. Mice can be infected with SARS-CoV; however, mouse and rat ACE2 does not support SARS-CoV-2 infection. Murine models for COVID-19 are induced through genetic adaptation of SARS-CoV-2, creation of chimeric SARS-CoV and SARS-CoV-2 viruses, use of human ACE2 knock-in and transgenic mice, and viral transfection of wild-type mice with human ACE2. Core aspects of COVID-19 are faithfully reproduced across species and model. These include the acute nature and predominantly respiratory source of viral shedding, acute transient and nonfatal disease with a largely pulmonary phenotype, similar short-term immune responses, and age-enhanced disease. Severity of disease and tissue involvement (particularly brain) in transgenic mice varies by promoter. To date, these models have provided a remarkably consistent template on which to test therapeutics, understand immune responses, and test vaccine approaches. The role of comorbidity in disease severity and the range of severe organ-specific pathology in humans remains to be accurately modeled.
Abstract
HIV-1 infects CD4+ T cells and macrophages and is currently incurable due to a latent reservoir. Targeting infected cells using TCR-mimic antibodies to peptide-MHC (pMHC) would provide a ...specific, high-affinity platform for immune system activation and monitoring antigen processing. However, antibodies to pMHC are notoriously difficult to isolate. Using a phage display platform, we panned for phage expressing variable fragments against immunodominant HIV pMHC complexes. These Fab fragments were cloned into a bispecific antibody (bsAb) backbone, such that one Fab fragment is specific for an HIV pMHC and the other fragment binds to CD3. These antibodies utilize the sensitivity of T cell signaling as readouts for antigen processing and potentially as therapeutic formats. Using this approach, we have shown that bsAbs specific for the most conserved MHC-II HIV capsid epitope (Gag293) can recognize the processed epitope on human monocyte-derived dendritic cells (moDCs) fed with the whole Gag protein antigen. Recognition is exquisitely epitope-specific. Additionally, human monocyte-derived macrophages infected with HIV were able to present Gag293 using the endogenous MHC-II pathway, as read out by a Gag-specific bsAb. To our knowledge, this is the first description of endogenous class II presentation of HIV in a major cell type that supports viral replication. By developing bsAbs to detect HIV peptide presentation, we can begin to address the kinetics, pathways, and cell types contributing to the priming events in early HIV infection, which will inform improved vaccine therapies. Additionally, given the potential for therapeutic application, these bsAbs may be used to redirect cytolytic effector cells towards infected targets.
Abstract
Background
The development of a safe and effective vaccine to prevent chronic hepatitis C virus (HCV) infection is a critical component of elimination efforts, providing the rationale for ...the first HCV vaccine efficacy trial.
Methods
In a randomized, multicenter, double-blind, placebo-controlled efficacy trial (NCT01436357), we evaluated a recombinant chimpanzee adenovirus 3 vector vaccine prime followed by a recombinant modified vaccinia Ankara boost, both encoding nonstructural proteins of HCV. HCV-uninfected adults 18–45 years old at-risk for HCV infection due to injection drug use were randomized to receive the prime-boost regimen or placebo at Days 0 and 56. Trial participants were monitored for vaccine reactogenicity, adverse events, and HCV viremia. Vaccine safety, immunogenicity, and efficacy against progression to chronic HCV infection were assessed.
Results
A total of 455 subjects received the prime-boost regimen or two doses of placebo, with 202 and 199 in the respective groups included in the according-to-protocol efficacy cohort. Overall incidence of infection was 14.1 infections per 100 person-years. There were no differences in development of chronic infection between vaccine and placebo arms, with 14 chronically infected subjects in each group. Specifically, the vaccine efficacy in preventing chronic infection was −0.53 (95% confidence interval CI, −2.5 to 0.34). Of vaccinated subjects, 78% generated T-cell responses to ≥1 vaccine-encoded HCV antigens. The vaccine was generally safe and well tolerated with no serious vaccine-related adverse events. There were more solicited reports of adverse events after either injection in the vaccine group (81%) than in the placebo group (59%), with the difference mainly due to injection-site reactions. Serious adverse events and deaths occurred with similar frequencies in the two groups.
Conclusion
A randomized, placebo controlled, Phase I/II trial of a prime-boost vaccine to prevent chronic HCV infection was completed in an at-risk population, demonstrating the feasibility of conducting rigorous vaccine research in people who inject drugs. The regimen elicited robust immune responses without evident safety concerns, but did not provide protection against chronic HCV infection.
Disclosures
Ventzislav Vassilev, PhD, GlaxoSmithKlein Vaccines (Employee), Lan Lin, MD, GlaxoSmithKlein Vaccines (Employee), Alfredo Nicosia, PhD, ReiThera (Employee, Shareholder), Antonella Folgori, PhD, ReiThera (Employee), ReiThera (Employee, Shareholder. Other Authors: No reported disclosures.
HIV infection increasingly affects populations that may not appear at high risk based on the use of some traditional targeting strategies. To shed some light on how to more sensitively/effectively ...identify people who need routine HIV testing and counseling, the objective of this study is to determine the prevalence of HIV infection in North Carolina state mental hospitals and to evaluate clinician judgment as a tool for targeting HIV counseling and testing. The design used is a blinded seroprevalence study. The study population includes all patients admitted to North Carolina state mental hospitals between March 1st and May 31st, 1994. The main outcome measures are the HIV seroprevalence, demographic and diagnostic features, and clinician assessment of the likelihood of HIV infection. The results of the study find that of 2159 study subjects, 35 persons (1.6%) were infected with HIV; of these, 14 (40%) were not previously known to be infected. All 35 HIV infections occurred in persons aged 13-59 years. Within this age group, infection rates were significantly higher for Blacks, males, persons who had a diagnosis of organic brain disease, and persons who had multiple psychiatric diagnoses. However, testing strategies that targeted any of the higher risk groups were insensitive. The rate of HIV infection for persons judged by the admitting clinician to have a high or intermediate likelihood of HIV infection was 26.4 times higher than the rate for those judged to have a low likelihood of infection (2.1 vs. 0.1%, 95% confidence intervals: 3.5-201.3). Of the 14 previously undiagnosed HIV-infected persons, 13 were judged by clinicians to have a high or intermediate likelihood of HIV infection. Moreover, 1258 persons were correctly assessed to have a low likelihood of infection. Conclusions from this study are that an HIV counseling and testing strategy targeting persons (in this setting aged 13-59 years) who were judged by clinicians to have a high or intermediate likelihood of infection, would have identified more than 90% of previously undetected infections while substantially reducing the number of negative HIV tests performed.
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