Daniel E Kaufmann

Daniel E Kaufmann
Université de Montréal | UdeM · Department of Medicine

M.D

About

286
Publications
24,301
Reads
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12,304
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Introduction
Daniel Kaufmann is a physician scientist. He is Professor of Medicine at the University of Montreal and its Hospital Research Center (CRCHUM). His laboratory focuses on the immunovirology of HIV and SARS-CoV-2 to develop vaccination and cure strategies. The major research areas are: i) the understanding of effective CD4 help in antiviral immunity; ii) the causes of virus-specific T cell impairment; iii) single-cell studies of HIV reservoirs; iv) COVID-19 pathogenesis and vaccine immunity.
Additional affiliations
June 2018 - present
University of Montreal Hospital Research Centre
Position
  • Professor (Full)
May 2015 - June 2019
Université de Montréal
Position
  • Managing Director
November 2012 - May 2018
University of Montreal Hospital Research Centre
Position
  • Professor (Associate)

Publications

Publications (286)
Article
Full-text available
Dysfunction of virus-specific CD4⁺ T cells in chronic human infections is poorly understood. We performed genome-wide transcriptional analyses and functional assays of CD4⁺ T cells specific for human immunodeficiency virus (HIV) from HIV-infected people before and after initiation of antiretroviral therapy (ART). A follicular helper T cell (TFH cel...
Article
Full-text available
Combination antiretroviral therapy (ART) is highly effective in controlling human immunodeficiency virus (HIV)-1 but requires lifelong medication due to the existence of a latent viral reservoir. Potent broadly neutralizing antibodies (bNAbs) represent a potential alternative or adjuvant to ART. In addition to suppressing viremia, bNAbs may have T...
Article
Full-text available
Although understanding the diversity of HIV-1 reservoirs is key to achieving a cure, their study at the single-cell level in primary samples remains challenging. We combine flow cytometric multiplexed fluorescent in situ RNA hybridization for different viral genes with HIV-1 p24 protein detection, cell phenotyping, and downstream near-full-length s...
Article
Full-text available
Despite advances in COVID-19 management, identifying patients evolving toward death remains challenging. To identify early predictors of mortality within 60 days of symptom onset (DSO), we performed immunovirological assessments on plasma from 279 individuals. On samples collected at DSO11 in a discovery cohort, high severe acute respiratory syndro...
Article
Full-text available
Spacing of the BNT162b2 mRNA doses beyond 3 weeks raises concerns about vaccine efficacy. We longitudinally analyze B cell, T cell and humoral responses to two BNT162b2 mRNA doses administered 16 weeks apart in 53 SARS-CoV-2 naïve and previously-infected donors. This regimen elicits robust RBD-specific B cell responses whose kinetics differ between...
Preprint
Antiretroviral therapy (ART) generally suppresses HIV replication to undetectable levels in peripheral blood, but immune activation associated with increased morbidity and mortality is sustained during ART, and infection rebounds when treatment is interrupted. To identify drivers of immune activation and potential sources of viral rebound, we modif...
Preprint
While SARS-CoV-2 mRNA vaccination has been shown to be safe and effective in the general population, immunocompromised solid organ transplant recipients (SOTR) were reported to have impaired immune responses after one or two doses of vaccine. In this study, we examined humoral responses induced after the second and the third dose of mRNA vaccine in...
Article
Full-text available
Introduction COVID-19 vaccine efficacy has been evaluated in large clinical trials and in real-world situation. Although they have proven to be very effective in the general population, little is known about their efficacy in immunocompromised patients. HIV-infected individuals’ response to vaccine may vary according to the type of vaccine and thei...
Preprint
Due to the recrudescence of SARS-CoV-2 infections worldwide, mainly caused by Omicron BA.1 and BA.2 variants of concern, several jurisdictions are administering a mRNA vaccine boost. Here, we analyzed humoral responses induced after the second and third doses of mRNA vaccine in naïve and previously-infected donors who received their second dose wit...
Article
Full-text available
SARS-CoV-2 infection rapidly elicits anti-Spike antibodies whose quantity in plasma gradually declines upon resolution of symptoms. This decline is part of the evolution of an immune response leading to B cell differentiation into short-lived antibody-secreting cells or resting memory B cells. At the same time, the ongoing class switch and antibody...
Article
Full-text available
Continuous emergence of SARS-CoV-2 variants of concern (VOC) is fueling the COVID-19 pandemic. Omicron (B.1.1.529) rapidly spread worldwide. The large number of mutations in its Spike raise concerns about a major antigenic drift that could significantly decrease vaccine efficacy and infection-induced immunity. A long interval between BNT162b2 mRNA...
Chapter
HIV-infected cells are difficult to characterize in vivo because of their great paucity and their diversity. This chapter describes a duplexed flow cytometry method that enables detection, quantification and phenotyping of these rare cells at single-cell resolution. Primary CD4⁺ T cells are enriched from PBMCs, stained for surface and intracellular...
Preprint
Full-text available
Continuous emergence of SARS-CoV-2 variants of concern (VOC) is fueling the COVID-19 pandemic. Omicron (B.1.1.529), is rapidly spreading worldwide. The large number of mutations in its Spike raised concerns about a major antigenic drift that could significantly decrease vaccine efficacy and infection-induced immunity. A long interval between BNT162...
Preprint
Full-text available
Spacing of the BNT162b2 mRNA doses beyond 3 weeks raised concerns about vaccine efficacy. We longitudinally analyzed B cell, T cell and humoral responses to two BNT162b2 mRNA doses administered 16 weeks apart in 53 SARS-CoV-2 naive and previously-infected donors. This regimen elicited robust RBD-specific B cell responses whose kinetics differed bet...
Article
The standard regimen of the BNT162b2 mRNA vaccine for SARS-CoV-2 includes two doses administered three weeks apart. However, some public health authorities spaced these doses, raising questions about efficacy. We analyzed longitudinal humoral responses against the D614G strain and variants of concern for SARS-CoV-2 in a cohort of SARS-CoV-2 naïve a...
Article
Full-text available
The efficacy of convalescent plasma for coronavirus disease 2019 (COVID-19) is unclear. Although most randomized controlled trials have shown negative results, uncontrolled studies have suggested that the antibody content could influence patient outcomes. We conducted an open-label, randomized controlled trial of convalescent plasma for adults with...
Preprint
Full-text available
Predicting COVID-19 severity is difficult, and the biological pathways involved are not fully understood. To approach this problem, we measured 4,701 circulating human protein abundances in two independent cohorts totaling 986 individuals. We then trained prediction models including protein abundances and clinical risk factors to predict adverse CO...
Preprint
Full-text available
Background: Antigen-specific T cell impairment is observed in chronic infections. CD4+ T cells are diverse in phenotype and function; how their different lineages are impacted by inhibitory immune checkpoints (IC) is unknown. Methods: We examined IC expression and function in HIV-specific CD4+ T cells of viremic individuals prior to ART initiation...
Preprint
Full-text available
While the standard regimen of the BNT162b2 mRNA vaccine includes two doses administered three weeks apart, some public health authorities decided to space them, raising concerns about vaccine efficacy. Here, we analyzed longitudinal humoral responses including antibody binding, Fc-mediated effector functions and neutralizing activity against the D6...
Preprint
Full-text available
Introduction: COVID-19 vaccine efficacy has been evaluated in large clinical trials and in real-world situation. Although they have proven to be very effective in the general population, little is known about their efficacy in immunocompromised patients. HIV-infected individuals response to vaccine may vary according to the type of vaccine and thei...
Article
Neutralizing antibodies (NAbs) are effective in treating COVID-19 but the mechanism of immune protection is not fully understood. Here, we applied live bioluminescence imaging (BLI) to monitor the real-time effects of NAb treatment during prophylaxis and therapy of K18-hACE2 mice intranasally infected with SARS-CoV-2-nanoluciferase. Real time imagi...
Article
SARS-CoV-2 whole genome sequencing is a molecular biology tool performed to support many aspects of the response to the pandemic. Freezing of primary clinical nasopharyngeal swabs and shipment to reference laboratories is usually required for sequencing. Cobas PCR Media transport medium facilitates high throughput SARS-CoV-2 RT-PCR analyses on coba...
Article
The impact of the microbiome on HIV disease is widely acknowledged although the mechanisms downstream of fluctuations in microbial composition remain speculative. We detected rapid, dynamic changes in translocated microbial constituents during two years after cART initiation. An unbiased systems biology approach revealed two distinct pathways drive...
Article
While the standard regimen of the BNT162b2 mRNA vaccine for SARS-CoV-2 includes two doses administered three weeks apart, some public health authorities are spacing these doses, raising concerns about efficacy. However, data indicate that a single dose can be up to 90% effective starting 14 days post administration. To assess the mechanisms contrib...
Article
Full-text available
Persistent immune activation and inflammation in people living with HIV (PLWH) are associated with immunosenescence, premature aging and increased risk of non-AIDS comorbidities, with the underlying mechanisms not fully understood. In this study, we show that downregulation of the T-cell immunoglobulin receptor CD96 on CD8 ⁺ T cells from PLWH is as...
Article
Full-text available
SARS-CoV-2 infection causing the novel coronavirus disease 2019 (COVID–19) has been responsible for more than 2.8 million deaths and nearly 125 million infections worldwide as of March 2021. In March 2020, the World Health Organization determined that the COVID–19 outbreak is a global pandemic. The urgency and magnitude of this pandemic demanded im...
Article
Full-text available
With the recent approval of highly effective COVID-19 vaccines, functional and lasting immunity to SARS-CoV-2 is currently under investigation as antibody levels in plasma were shown to decline during convalescence. Since the absence of antibodies does not equate to absence of immune memory, we evaluate the presence of SARS-CoV-2-specific memory B...
Article
Small CD4-mimetic compounds (CD4mc) sensitize HIV-1-infected cells to antibody-dependent cellular cytotoxicity (ADCC) by facilitating antibody recognition of epitopes that are otherwise occluded on the unliganded viral envelope (Env). Combining CD4mc with two families of CD4-induced (CD4i) antibodies, which are frequently found in plasma of HIV-1-i...
Article
Full-text available
To identify circulating proteins influencing Coronavirus Disease 2019 (COVID-19) susceptibility and severity, we undertook a two-sample Mendelian randomization (MR) study, rapidly scanning hundreds of circulating proteins while reducing bias due to reverse causation and confounding. In up to 14,134 cases and 1.2 million controls, we found that an s...
Preprint
Full-text available
Neutralizing antibodies (NAbs) are effective in treating COVID-19 but the mechanism of immune protection is not fully understood. Here, we applied live bioluminescence imaging (BLI) to monitor the real-time effects of NAb treatment in prophylaxis and therapy of K18-hACE2 mice intranasally infected with SARS-CoV-2-nanoluciferase. We visualized seque...
Article
Neutralizing antibodies (NAbs) are effective in treating COVID-19 but the mechanism of immune protection is not fully understood. Here, we applied live bioluminescence imaging (BLI) to monitor the real-time effects of NAb treatment in prophylaxis and therapy of K18-hACE2 mice intranasally infected with SARS-CoV-2-nanoluciferase. We visualized seque...
Preprint
Full-text available
Despite advances in COVID-19 management, it is unclear how to recognize patients who evolve towards death. This would allow for better risk stratification and targeting for early interventions. However, the explosive increase in correlates of COVID-19 severity complicates biomarker prioritisation. To identify early biological predictors of mortalit...
Preprint
Full-text available
The standard dosing of the Pfizer/BioNTech BNT162b2 mRNA vaccine validated in clinical trials includes two doses administered three weeks apart. While the decision by some public health authorities to space the doses because of limiting supply has raised concerns about vaccine efficacy, data indicate that a single dose is up to 90% effective starti...
Article
Dysregulated immune profiles have been described in symptomatic SARS-CoV-2-infected patients. Whether the reported immune alterations are specific to SARS-CoV-2 infection or also triggered by other acute illnesses remains unclear. We performed flow cytometry analysis on fresh peripheral blood from a consecutive cohort of i) patients hospitalized wi...
Preprint
Full-text available
SARS-CoV-2 whole genome sequencing is an important molecular biology tool performed to support many aspects of the response to the pandemic. Freezing of primary clinical nasopharyngeal swab samples and shipment to reference laboratories is usually required since RNA sequencing is rarely available in routine clinical microbiology laboratories where...
Preprint
Full-text available
Functional and lasting immune responses to the novel coronavirus (SARS-CoV-2) are currently under intense investigation as antibody titers in plasma have been shown to decline during convalescence. Since the absence of antibodies does not equate to absence of immune memory, we sought to determine the presence of SARS-CoV-2-specific memory B cells i...
Preprint
Full-text available
Dysregulated immune profiles have been described in symptomatic SARS-CoV-2-infected patients. Whether the reported immune alterations are specific to SARS-CoV-2 infection or also triggered by other acute illnesses remains unclear. We performed flow cytometry analysis on fresh peripheral blood from a consecutive cohort of i) patients hospitalized wi...
Preprint
Full-text available
word count: 231) Proteins detectable in peripheral blood may influence COVID-19 susceptibility or severity. However, understanding which circulating proteins are etiologically involved is difficult because their levels may be influenced by COVID-19 itself and also subject to confounding factors. To identify circulating proteins influencing COVID-19...
Article
Full-text available
While waiting for an efficient vaccine to protect against SARS-CoV-2 infection, alternative approaches to treat or prevent acute COVID-19 are urgently needed. Transfusion of convalescent plasma to treat COVID-19 patients is currently being explored; neutralizing activity in convalescent plasma is thought to play a central role in the efficacy of th...
Preprint
Full-text available
In the absence of effective vaccines and with limited therapeutic options, convalescent plasma is being collected across the globe for potential transfusion to COVID-19 patients. The therapy has been deemed safe and several clinical trials assessing its efficacy are ongoing. While it remains to be formally proven, the presence of neutralizing antib...
Article
Full-text available
Background: Increased intestinal barrier permeability and subsequent gut microbial translocation are significant contributors to inflammatory non-AIDS comorbidities in people living with HIV (PLWH). Evidence in animal models have shown that markers of intestinal permeability and microbial translocation vary over the course of the day and are affec...
Article
Full-text available
Background Untreated HIV infection leads to alterations in HIV-specific CD4⁺ T cells including increased expression of co-inhibitory receptors (IRs) and skewing toward a T follicular helper cell (Tfh) signature. However, which changes are maintained after suppression of viral replication with antiretroviral therapy (ART) is poorly known. Methods W...
Article
Full-text available
The HIV-1 envelope (Env) undergoes conformational changes during infection. Broadly neutralizing antibodies (bNAbs) are typically isolated by using soluble Env trimers, which do not capture all Env states. To address these limitations, we devised a vesicular stomatitis virus (VSV)-based probe to display membrane-embedded Env trimers and isolated fi...
Article
Full-text available
The need for definitive answers probably explains our natural tendency to seek simplicity. The reductionist “bulk” approach, in which a mean behavior is attributed to a heterogeneous cell population, fulfills this need by considerably helping the conceptualization of complex biological processes. However, the limits of this methodology are becoming...
Preprint
Background Gut microbial translocation and increased intestinal barrier permeability are significant contributors to inflammatory non-AIDS co-morbidities in people living with HIV (PLWH). However, daily variations of markers of bacterial and fungal translocation along with intestinal damage are not characterized yet. Herein, we assessed the variati...
Preprint
Background: Increased intestinal barrier permeability and subsequent gut microbial translocation are significant contributors to inflammatory non-AIDS comorbidities in people living with HIV (PLWH). Evidence in animal models have shown that markers of intestinal permeability and microbial translocation vary over the course of the day and are affect...
Preprint
Full-text available
Background: Increased intestinal barrier permeability and subsequent gut microbial translocation are significant contributors to inflammatory non-AIDS comorbidities in people living with HIV (PLWH). Evidence in animal models have shown that markers of intestinal permeability and microbial translocation vary over the course of the day and are affect...
Article
Along with other immune checkpoints, T cell i mmunoglobulin and m ucin domain-containing protein 3 (Tim-3) is expressed on exhausted CD4 ⁺ and CD8 ⁺ T cells and is upregulated on the surface of these cells upon infection by H uman I mmunodeficiency V irus Type 1 (HIV-1). Recent reports have suggested an antiviral role for Tim-3. However, the molecu...
Article
Full-text available
The restriction factor BST-2 and the NK cell ligands NTB-A and PVR are among a growing list of membrane proteins found to be downregulated by HIV-1 Vpu. BST-2 antagonism enhances viral release, while NTB-A and PVR downmodulation contributes to NK cell evasion. However, it remains unclear how Vpu can target multiple cellular factors simultaneously....
Article
Full-text available
Genetic and immunologic analyses of epidemiologically-linked HIV transmission enable insights into the impact of immune responses on clinical outcomes. Human vaccine trials and animal studies of HIV-1 infection have suggested immune correlates of protection; however, their role in natural infection in terms of protection from disease progression is...
Article
The HIV-1 envelope glycoprotein (Env) (gp120-gp41) 3 is the target for neutralizing antibodies and antibody-dependent cellular cytotoxicity (ADCC). HIV-1 Env is flexible, sampling different conformational states. Before engaging CD4, Env adopts a closed conformation (State 1) that is largely antibody resistant. CD4 binding induces an intermediate s...
Article
Rationale Tumor infiltrating lymphocytes are widely associated with positive outcomes, yet carry key indicators of a systemic failed immune response against unresolved cancer. Cancer immunotherapies can reverse their tolerance phenotypes, while preserving tumor-reactivity and neoantigen-specificity shared with circulating immune cells. Objectives W...
Article
Full-text available
The phenotypic characterization of the cells in which HIV persists during antiretroviral therapy (ART) remains technically challenging. We developed a simple flow cytometry-based assay to quantify and characterize infected cells producing HIV proteins during untreated and treated HIV infection. By combining two antibodies targeting the HIV capsid i...
Data
MFI of p24 antibodies following stimulation. Comparison of the MFI of the two p24 antibodies (p24 28B7-APC and p24 KC57-PE) in the presence or absence of stimulation with PMA/ionomycin in samples from 6 untreated individuals. The MFI of p24 antibodies was measured within the p24+ gate (p24 KC57+/p24 28B7+). (TIF)
Data
Comparison of two permeabilization buffers for the detection of p24-producing cells by HIV-Flow. Dot plots showing the detection of p24+ cells in 2 samples, using 2 experimental conditions. Purified CD4 T cells from a viremic individual were rested for 18 hours, while purified CD4 T cells from an ART-suppressed individual were stimulated with PMA/i...
Data
Markers showing significant changes of expression following stimulation. (A) Representative dot plots showing the levels of expression of CXCR3/CCR4/CCR6 after 24h of resting or after 24h of stimulation with PMA/ionomycin + BFA in one representative ART-suppressed individual. (B) As in A) for CXCR5 and CD25. (C) As in A) for CD3 and CD4. Of note, t...
Data
Gating strategy used in HIV-Flow. Example of the gating strategy used for a representative sample following PMA/ionomycin stimulation of CD4+ T cells obtained from an ART-suppressed individual. (TIF)
Data
Frequencies of infected cells measured by different assays in samples from ART-suppressed individuals. (DOCX)
Data
Characterization of p24 KC57 and p24 28B7 antibodies. (A) Representative dot plots obtained from a binding competition experiment. Staining with either KC57 or 28B7 in a first step (1) does not prevent subsequent staining with the other antibody (2) (middle and right panels). Co-staining with both antibodies yielded a similar frequency of p24+ cell...
Data
Single positive cells contain low HIV DNA levels. (A) Representative dot plot showing the gating strategy used to sort four populations of unstimulated cells (KC57+/28B7+, KC57+, 28B7+ and KC57-/28B7- cells) obtained from one untreated individual (VIR21). Total HIV DNA was quantified by ultrasensitive PCR in each sorted subset (right). (B) Levels o...