Pharmacologically-induced activation of replication competent proviruses from latency in the presence of antiretroviral treatment (ART) has been proposed as a step towards curing HIV-1 infection. ...However, until now, approaches to reverse HIV-1 latency in humans have yielded mixed results. Here, we report a proof-of-concept phase Ib/IIa trial where 6 aviremic HIV-1 infected adults received intravenous 5 mg/m2 romidepsin (Celgene) once weekly for 3 weeks while maintaining ART. Lymphocyte histone H3 acetylation, a cellular measure of the pharmacodynamic response to romidepsin, increased rapidly (maximum fold range: 3.7–7.7 relative to baseline) within the first hours following each romidepsin administration. Concurrently, HIV-1 transcription quantified as copies of cell-associated un-spliced HIV-1 RNA increased significantly from baseline during treatment (range of fold-increase: 2.4–5.0; p = 0.03). Plasma HIV-1 RNA increased from <20 copies/mL at baseline to readily quantifiable levels at multiple post-infusion time-points in 5 of 6 patients (range 46–103 copies/mL following the second infusion, p = 0.04). Importantly, romidepsin did not decrease the number of HIV-specific T cells or inhibit T cell cytokine production. Adverse events (all grade 1–2) were consistent with the known side effects of romidepsin. In conclusion, romidepsin safely induced HIV-1 transcription resulting in plasma HIV-1 RNA that was readily detected with standard commercial assays demonstrating that significant reversal of HIV-1 latency in vivo is possible without blunting T cell-mediated immune responses. These finding have major implications for future trials aiming to eradicate the HIV-1 reservoir.
clinicaltrials.gov NTC02092116.
Introduction of vaccines against COVID-19 has provided the most promising chance to control the world-wide COVID-19 pandemic. However, the adenovirus-vector based Oxford/AstraZeneca ChAdOx1 (AZ) and ...Johnson & Johnson Ad26.CoV2.S COVID-19 vaccines have been linked with serious thromboembolic events combined with thrombocytopenia, denominated Vaccine-induced Immune Thrombocytopenia and Thrombosis (VITT). The pathogenesis of COVID-19 VITT remain incompletely understood; especially the initial events that trigger platelet activation, platelet factor (PF)4 release, complex formation and PF4 antibody production are puzzling. This is a prospective study investigating the impact of different COVID-19 vaccines on inflammation (CRP, TNF-α, IL-1β, IL-6, IL-8, IL-10), vascular endothelial activation (syndecan-1, thrombomodulin, E-selectin, ICAM-1, ICAM-3, VCAM-1), platelet activation (P-selectin, TGF-β, sCD40L) and aggregation (Multiplate
impedance aggregometry), whole blood coagulation (ROTEM
), thrombin generation and PF4 antibodies to reveal potential differences between AZ and mRNA vaccines in individuals without VITT. The study included 80 (55 AZ and 55 mRNA) vaccinated individuals and 55 non-vaccinated age- and gender matched healthy controls. The main findings where that both vaccines enhanced inflammation and platelet activation, though AZ vaccination induced a more pronounced increase in several inflammatory and platelet activation markers compared to mRNA vaccination and that post-vaccination thrombin generation was higher following AZ vaccination compared to mRNA vaccination. No difference in neither the PF4 antibody level nor the proportion of individuals with positive PF4 antibodies were observed between the vaccine groups. This is the first study to report enhanced inflammation, platelet activation and thrombin generation following AZ vaccination compared to mRNA vaccination in a head-to-head comparison. We speculate that specific components of the AZ adenovirus vector may serve as initial trigger(s) of (hyper)inflammation, platelet activation and thrombin generation, potentially lowering the threshold for a cascade of events that both trigger complications related to excessive inflammation, platelet and coagulation activation as observed in epidemiological studies and promote development of VITT when combined with high-titer functionally active PF4 antibodies.
Abstract
Background
The objective of this study was to perform a seroprevalence survey on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among Danish healthcare workers to identify ...high-risk groups.
Methods
All healthcare workers and administrative personnel at the 7 hospitals, prehospital services, and specialist practitioner clinics in the Central Denmark Region were invited to be tested by a commercial SARS-CoV-2 total antibody enzyme-linked immunosorbent assay (Wantai Biological Pharmacy Enterprise Co, Ltd, Beijing, China).
Results
A total of 25 950 participants were invited. Of these, 17 971 had samples available for SARS-CoV-2 antibody testing. After adjustment for assay sensitivity and specificity, the overall seroprevalence was 3.4% (95% confidence interval CI, 2.5%–3.8%). The seroprevalence was higher in the western part of the region than in the eastern part (11.9% vs 1.2%; difference: 10.7 percentage points 95% CI, 9.5–12.2). In the high-prevalence area, the emergency departments had the highest seroprevalence (29.7%), whereas departments without patients or with limited patient contact had the lowest seroprevalence (2.2%). Among the total 668 seropositive participants, 433 (64.8%) had previously been tested for SARS-CoV-2 RNA, and 50.0% had a positive reverse-transcription polymerase chain reaction (PCR) result.
Conclusions
We found large differences in the prevalence of SARS-CoV-2 antibodies in staff working in the healthcare sector within a small geographical area of Denmark. Half of all seropositive staff had been tested positive by PCR prior to this survey. This study raises awareness of precautions that should be taken to avoid in-hospital transmission. Regular testing of healthcare workers for SARS-CoV-2 should be considered to identify areas with increased transmission.
Severe acute respiratory syndrome coronavirus 2 seroprevalence among healthcare workers in the Central Denmark Region showed large geographical differences (1%–12%). The risk of infection was associated with workplace, rather than location of residence.
Toll-like receptors (TLRs) are a family of pattern recognition receptors and part of the first line of defense against invading microbes. In humans, we know of 10 different TLRs, which are expressed ...to varying degrees in immune cell subsets. Engaging TLRs through their specific ligands leads to activation of the innate immune system and secondarily priming of the adaptive immune system. Because of these unique properties, TLR agonists have been investigated as immunotherapy in cancer treatment for many years, but in recent years there has also been growing interest in the use of TLR agonists in the context of human immunodeficiency virus type 1 (HIV-1) cure research. The primary obstacle to curing HIV-1 is the presence of a latent viral reservoir in transcriptionally silent immune cells. Due to the very limited transcription of the integrated HIV-1 proviruses, latently infected cells cannot be targeted and cleared by immune effector mechanisms. TLR agonists are very interesting in this context because of their potential dual effects as latency reverting agents (LRAs) and immune modulatory compounds. Here, we review preclinical and clinical data on the impact of TLR stimulation on HIV-1 latency as well as antiviral and HIV-1-specific immunity. We also focus on the promising role of TLR agonists in combination strategies in HIV-1 cure research. Different combinations of TLR agonists and broadly neutralizing antibodies or TLRs agonists as adjuvants in HIV-1 vaccines have shown very encouraging results in non-human primate experiments and these concepts are now moving into clinical testing.
Abstract
SARS-CoV-2 variants of concern have continuously evolved and may erode vaccine induced immunity. In this observational cohort study, we determine the risk of breakthrough infection in a ...fully vaccinated cohort. SARS-CoV-2 anti-spike IgG levels were measured before first SARS-CoV-2 vaccination and at day 21–28, 90 and 180, as well as after booster vaccination. Breakthrough infections were captured through the Danish National Microbiology database. incidence rate ratio (IRR) for breakthrough infection at time-updated anti-spike IgG levels was determined using Poisson regression. Among 6076 participants, 127 and 364 breakthrough infections due to Delta and Omicron variants were observed. IRR was 0.29 (95% CI 0.15–0.56) for breakthrough infection with the Delta variant, comparing the highest and lowest quintiles of anti-spike IgG. For Omicron, no significant differences in IRR were observed. These results suggest that quantitative level of anti-spike IgG have limited impact on the risk of breakthrough infection with Omicron.
DESIGN:This was an exploratory, single-arm clinical trial that tested the immune enhancement effects of 24-weeks of Toll-like receptor 9 (TLR9) agonist (MGN1703; Lefitolimod; 60 mg × 2 weekly) ...therapy.
METHODS:We enrolled HIV-1-infected individuals on suppressive combination antiretroviral therapy. Safety was assessed throughout the study. The primary outcome was reduction in total CD4 T-cell viral DNA levels. Secondary outcomes included safety, detailed immunological and virological analyses, and time to viral rebound (viral load > 5000 copies/ml) after randomization into an analytical treatment interruption (ATI).
RESULTS:A total of 12 individuals completed the treatment phase and nine completed the ATI. Adverse events were limited and consistent with previous reports for MGN1703. Although the dosing regimen led to potent T-cell activation and increased HIV-1-specific T-cell responses, there were no cohort-wide changes in persistent virus (total CD4 T cells viral DNA; P = 0.34). No difference in time to rebound was observed between the ATI arms (log rank P = 0.25). One of nine ATI participants, despite harboring a large replication-competent reservoir, controlled viremia for 150 days via both HIV-1-specific cellular and antibody-mediated immune responses.
CONCLUSION:A period of 24 weeks of MGN1703 treatment was safe and improved innate as well as HIV-1-specific adaptive immunity in HIV-1+ individuals. These findings support the incorporation of TLR9 agonism into combination HIV-1 cure strategies.
TRIAL NAME AND REGISTRATION:TLR9 Enhancement of antiviral immunity in chronic HIV-1 infectiona phase 1B/2A trial; ClinicalTrials.gov NCT02443935.
Chimeric Antigen Receptor (CAR) T cell therapies are tremendously successful in hematological malignancies and show great promise as treatment and curative strategy for HIV. A major determinant for ...effective CAR T cell therapy is the persistence of CAR T cells. Particularly, antigen density and target cell abundance are crucial for the engagement, engraftment, and persistence of CAR T cells. The success of HIV-specific CAR T cells is challenged by limited antigen due to low cell surface expression of viral proteins and the scarcity of chronically infected cells during antiretroviral therapy. Several strategies have been explored to increase the efficacy of CAR T cells by enhancing expansion and persistence of the engineered cells. This review highlights the challenges of designing CAR T cells against HIV and other chronic viral infections. We also discuss potential strategies to enhance CAR T cell expansion and persistence in the setting of low antigen exposure.
Oral administration of a combination of two or three antiretroviral drugs (cART) has transformed HIV from a life-threatening disease to a manageable infection. However, as the discontinuation of ...therapy leads to virus rebound in plasma within weeks, it is evident that, despite daily pill intake, the treatment is unable to clear the infection from the body. Furthermore, as cART drugs exhibit a much lower concentration in key HIV residual tissues, such as the brain and lymph nodes, there is a rationale for the development of drugs with enhanced tissue penetration. In addition, the treatment, with combinations of multiple different antiviral drugs that display different pharmacokinetic profiles, requires a strict dosing regimen to avoid the emergence of drug-resistant viral strains. An intriguing opportunity lies within the development of long-acting, synthetic scaffolds for delivering cART. These scaffolds can be designed with the goal to reduce the frequency of dosing and furthermore, hold the possibility of potential targeting to key HIV residual sites. Moreover, the synthesis of combinations of therapy as one molecule could unify the pharmacokinetic profiles of different antiviral drugs, thereby eliminating the consequences of sub-therapeutic concentrations. This review discusses the recent progress in the development of long-acting and tissue-targeted therapies against HIV for the delivery of direct antivirals, and examines how such developments fit in the context of exploring HIV cure strategies.
Humanized mouse models are used extensively in research involving human pathogens and diseases. However, most of these models require preconditioning. Radio-active sources have been used routinely ...for this purpose but safety issues have motivated researchers to transition to chemical or X-ray based preconditioning. In this study, we directly compare 350 kV X-ray and Cs-137 low-dose precondition of NOG mice before human stem cell transplantation. Based on flow cytometry data, we found that engraftment of human cells into the mouse bone marrow was similar between radiation sources. Likewise, human engraftment in the peripheral blood was comparable between Cs-137 and three different X-ray doses with equal chimerization kinetics. In primary lymphoid organs such as the thymus and lymph nodes, and spleen, liver and lung, human-to-mouse chimerization was also comparable between irradiation sources. Development of different CD4 and CD8 T cells as well as these cells' maturation stages, i.e. from naïve to effector and memory subsets were generally analogous. Based on our results, we conclude that there are no discernable differences between the two sources in the low-dose spectrum investigated. However, while we encourage the transition to X-ray-based sources, we recommend all research groups to consider technical specifications and dose-finding studies.
In simian-human immunodeficiency virus (SHIV)-infected non-human primates, broadly neutralizing antibodies (bNAbs) against the virus appear to stimulate T cell immunity. To determine whether this ...phenomenon also occurs in humans we measured HIV-1-specific cellular immunity longitudinally in individuals with HIV-1 starting antiviral therapy (ART) with or without adjunctive bNAb 3BNC117 treatment. Using the activation-induced marker (AIM) assay and interferon-γ release, we observe that frequencies of Pol- and Gag-specific CD8
T cells, as well as Gag-induced interferon-γ responses, are significantly higher among individuals that received adjunctive 3BNC117 compared to ART-alone at 3 and 12 months after starting ART. The observed changes in cellular immunity were directly correlated to pre-treatment 3BNC117-sensitivity. Notably, increased HIV-1-specific immunity is associated with partial or complete ART-free virologic control during treatment interruption for up to 4 years. Our findings suggest that bNAb treatment at the time of ART initiation maintains HIV-1-specific CD8
T cell responses that are associated with ART-free virologic control.
PDF
