Publications by authors named "Jonathan Angel"

COVID-19 breakthrough infection (BTI) can occur despite vaccination. Using a multi-centre, prospective, observational Canadian cohort of people with HIV (PWH) receiving ≥2 COVID-19 vaccines, we compared the SARS-CoV-2 spike (S) and receptor-binding domain (RBD)-specific IgG levels 3 and 6 months post second dose, as well as 1 month post third dose, in PWH with and without BTI. BTI was defined as positivity based on self-report measures (data up to last study visit) or IgG data (up to 1 month post dose 3).

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The numbers of organ donors in Canada and the USA fall short of increasing demand, resulting in increased morbidity, poor health outcomes, higher medical costs and death of many individuals waitlisted for transplantation. In the US, since 2013 when the US HIV Organ Policy Equity (HOPE) Act lifted the ban on organ donation between people living with HIV, the option of using organs from People with HIV became a reality. In Canada, HIV diagnosis was an exclusion criterion to organ donation until 2017, when permission was granted if requirements for 'exceptional distribution' could be met.

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Introduction: Alterations in the gut immune system have been implicated in various diseases.The challenge of obtaining gut tissues from healthy individuals, commonly performed via surgical explants, has limited the number of studies describing the phenotype and function of gut-derived immune cells in health.

Methods: Here, by means of recto-sigmoid colon biopsies obtained during routine care (colon cancer screening in healthy adults), the phenotype and function of immune cells present in the gut were described and compared to those found in blood.

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HIV persists in tissues during antiretroviral therapy (ART), but the relative contribution of different anatomical compartments to the viral reservoir in humans remains unknown. We performed an extensive characterization of HIV reservoirs in two men who donated their bodies to HIV cure research and who had been on suppressive ART for years. HIV DNA is detected in all tissues, with large variations across anatomical compartments and between participants.

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Background: Finding a cure for HIV is challenged by persisting reservoirs, the mapping of which necessitates invasive procedures. Inviting people with HIV (PWHIV) at the end of life to donate body specimens post-mortem through research autopsies is a novel approach, raising ethical concerns.

Objective: This case study aims to explore the motivations, barriers, and facilitators of a terminally-ill Canadian PWHIV who requested medical assistance in dying (MAID) and expressed interest in donating his body for HIV cure research.

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Background: The differentiation and function of immunosuppressive regulatory T cells (Tregs) is dictated by the master transcription factor FoxP3. During HIV infection, there is an increase in Treg frequencies in the peripheral blood and lymphoid tissues. This accentuates immune dysfunction and disease progression.

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Objectives: Many vaccines require higher/additional doses or adjuvants to provide adequate protection for people with HIV (PWH). Here, we compare coronavirus disease 2019 (COVID-19) vaccine-induced antibody neutralization capacity in PWH vs. HIV-negative individuals following two vaccine doses.

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Objective: To assess antiretroviral therapy (ART) adherence among people with HIV (PWH) in Canada and identify baseline characteristics associated with suboptimal adherence (<95%).

Design: Retrospective observational study using data from the National Prescription Drug Utilization Information System and Régie de l'assurance maladie Quebec (RAMQ) Public Prescription Drug Insurance Plan.

Methods: This analysis included PWH aged 18 years or older who initiated an ART regimen and were followed for at least 12 months (2010-2020).

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We have previously demonstrated spermicidal activity of LL-37 antimicrobial peptide on mouse/human sperm and its contraceptive effects in female mice. With its microbicidal action against Neisseria gonorrhoeae, LL-37 warrants development into a multipurpose prevention technology (MPT) agent for administering into the female reproductive tract (FRT). However, it is important to verify that multiple administrations of LL-37 do not lead to damage of FRT tissues and/or irreversible loss of fecundity.

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People living with HIV (PLWH) may be at risk for poor immunogenicity to certain vaccines, including the ability to develop immunological memory. Here, we assessed T-cell immunogenicity following three SARS-CoV-2 vaccine doses in PLWH versus uninfected controls. Blood was collected from 38 PLWH on antiretroviral therapy and 24 age-matched HIV-negative controls, pre-vaccination and after 1st/2nd/3rd dose of SARS-CoV-2 vaccines, without prior SARS-CoV-2 infection.

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Cabotegravir and rilpivirine long-acting (LA) antiretroviral therapy (ART) demonstrated similar safety and efficacy in maintaining viral suppression among participants switching from daily oral to LA ART in the Extension Phase of the FLAIR trial. The Phase IIIb SOLAR study comparing efficacy and safety of daily oral versus LA ART every 2 months allowed participants and health care providers (HCPs) to choose an oral lead-in (OLI) before LA initiation or proceed by immediately starting with injections (SWI). We conducted an online survey among SOLAR HCPs ( = 110) in 13 countries to assess reasons for choosing OLI versus SWI.

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Background: Many people living with HIV struggle to consistently adhere to antiretroviral therapy, fail to achieve long-term virologic control and remain at risk for HIV-related disease progression, development of resistance and may transmit HIV infection to others.

Objective: To determine if switching from current multi-tablet (curART) to single-tablet antiretroviral therapy (abacavir/lamivudine/dolutegravir; ABC/3TC/DTG), both combined with individualized adherence support, would improve HIV suppression in non-adherent vulnerable populations.

Methods: TriiADD was an investigator-initiated randomized, multicentre, open label study.

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Objectives: Many vaccines require higher/additional doses or adjuvants to provide adequate protection for people with HIV (PWH). Our objective was to compare COVID-19 vaccine immunogenicity in PWH to HIV-negative individuals.

Design: In a Canadian multi-center prospective, observational cohort of PWH receiving at least two COVID-19 vaccinations, we measured vaccine-induced immunity at 3 and 6 months post 2nd and 1-month post 3rd doses.

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Background: Accurate and timely testing for SARS-CoV-2 in the pediatric population is crucial to control the COVID-19 pandemic; saliva testing has been proposed as a less invasive alternative to nasopharyngeal swabs. We sought to compare the detection of SARS-CoV-2 using saliva versus nasopharyngeal swab in the pediatric population, and to determine the optimum time of testing for SARS-CoV-2 using saliva.

Methods: We conducted a longitudinal diagnostic study in Ottawa, Canada, from Jan.

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Study Question: Is 17BIPHE2, an engineered cathelicidin antimicrobial peptide with low susceptibility to proteases, a better spermicide in cervicovaginal fluid (CVF) than its parental peptides, LL-37 and GF-17?

Summary Answer: At the same mass concentration, 17BIPHE2 exhibited the highest spermicidal activity on human sperm resuspended in CVF-containing medium.

What Is Known Already: LL-37 and its truncated peptide GF-17 exert both spermicidal and microbicidal activities, although they are prone to proteolytic degradation in body fluids.

Study Design, Size, Duration: Spermicidal activities of 17BIPHE2 were evaluated in vitro in mouse and human sperm, both resuspended in medium, and then on human sperm incubated in CVF-containing medium; in the latter condition, the spermicidal activity and peptide stability in CVF of 17BIPHE2 were compared with that of LL-37 and GF-17.

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HIV cure research requires interrogating latent HIV reservoirs in deep tissues, which necessitates autopsies to avoid risks to participants. An HIV autopsy biobank would facilitate this research, but such research raises ethical issues and requires participant engagement. This study explores the willingness to participate in HIV cure research at the end of life.

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Introduction: Most existing vaccines require higher or additional doses or adjuvants to provide similar protection for people living with HIV (PLWH) compared with HIV-uninfected individuals. Additional research is necessary to inform COVID-19 vaccine use in PLWH.

Methods And Analysis: This multicentred observational Canadian cohort study will enrol 400 PLWH aged 16 years from Montreal, Ottawa, Toronto and Vancouver.

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HIV infection persists in different tissue reservoirs among people with HIV (PWH) despite effective antiretroviral therapy (ART). In the brain, lentiviruses replicate principally in microglia and trafficking macrophages. The impact of ART on this viral reservoir is unknown.

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Although combination antiretroviral therapy is extremely effective in lowering HIV RNA to undetectable levels in the blood, HIV persists in latently infected CD4 T-cells and persistently infected macrophages. In latently/persistently infected cells, HIV proteins have shown to affect the expression of proteins involved in the apoptosis pathway, notably the inhibitors of apoptosis proteins (IAPs), and thereby influence cell survival. IAPs, which are inhibited by endogenous second mitochondrial-derived activators of caspases (SMAC), can serve as targets for SMAC mimetics, synthetic compounds capable of inducing apoptosis.

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Macrophages serve as viral reservoirs due to their resistance to apoptosis and HIV-cytopathic effects. We have previously shown that inhibitor of apoptosis proteins (IAPs) confer resistance to HIV-Vpr-induced apoptosis in normal macrophages. Herein, we show that second mitochondrial activator of caspases (SMAC) mimetics (SM) induce apoptosis of monocyte-derived macrophages (MDMs) infected in vitro with a R5-tropic laboratory strain expressing heat stable antigen, chronically infected U1 cells, and ex-vivo derived MDMs from HIV-infected individuals.

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The coronavirus disease 2019 (COVID-19) pandemic requires the continued development of safe, long-lasting, and efficacious vaccines for preventive responses to major outbreaks around the world, and especially in isolated and developing countries. To combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we characterize a temperature-stable vaccine candidate (TOH-Vac1) that uses a replication-competent, attenuated vaccinia virus as a vector to express a membrane-tethered spike receptor binding domain (RBD) antigen. We evaluate the effects of dose escalation and administration routes on vaccine safety, efficacy, and immunogenicity in animal models.

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