ABSTRACT
Glucocorticoid synthesis by adrenal glands (AGs) is regulated by the hypothalamic-pituitary-adrenal axis to facilitate stress responses when the host is exposed to stimuli. Recent studies implicate macrophages as potential steroidogenic regulators, but the molecular mechanisms by which AG macrophages exert such influence remain unclear. In this study, we investigated the role of AG macrophages in response to cold challenge or atherosclerotic inflammation as physiologic models of acute or chronic stress. Using single-cell RNA sequencing, we observed dynamic AG macrophage polarization toward classical activation and lipid-associated phenotypes following acute or chronic stimulation. Among transcriptional alterations induced in macrophages, triggering receptor expressed on myeloid cells 2 (Trem2) was highlighted because of its upregulation following stress. Conditional deletion of macrophage Trem2 revealed a protective role in stress responses. Mechanistically, Trem2 deletion led to increased AG macrophage death, abolished the TGF-ß-producing capacity of AG macrophages, and resulted in enhanced glucocorticoid production. In addition, enhanced glucocorticoid production was replicated by blockade of TGF-ß signaling. Together, these observations suggest that AG macrophages restrict steroidogenesis through Trem2 and TGF-ß, which opens potential avenues for immunotherapeutic interventions to resolve stress-related disorders.
Subject(s)
Adrenal Glands , Glucocorticoids , Macrophages , Membrane Glycoproteins , Receptors, Immunologic , Transforming Growth Factor beta , Animals , Macrophages/metabolism , Macrophages/immunology , Mice , Membrane Glycoproteins/metabolism , Membrane Glycoproteins/genetics , Glucocorticoids/metabolism , Transforming Growth Factor beta/metabolism , Receptors, Immunologic/metabolism , Receptors, Immunologic/genetics , Adrenal Glands/metabolism , Male , Mice, Knockout , Mice, Inbred C57BL , Signal TransductionABSTRACT
After Mycobacterium tuberculosis (Mtb) infection, many effector T cells traffic to the lungs, but few become activated. Here we use an antigen receptor reporter mouse (Nur77-GFP) to identify recently activated CD4 T cells in the lungs. These Nur77-GFPHI cells contain expanded TCR clonotypes, have elevated expression of co-stimulatory genes such as Tnfrsf4/OX40, and are functionally more protective than Nur77-GFPLO cells. By contrast, Nur77-GFPLO cells express markers of terminal exhaustion and cytotoxicity, and the trafficking receptor S1pr5, associated with vascular localization. A short course of immunotherapy targeting OX40+ cells transiently expands CD4 T cell numbers and shifts their phenotype towards parenchymal protective cells. Moreover, OX40 agonist immunotherapy decreases the lung bacterial burden and extends host survival, offering an additive benefit to antibiotics. CD4 T cells from the cerebrospinal fluid of humans with HIV-associated tuberculous meningitis commonly express surface OX40 protein, while CD8 T cells do not. Our data thus propose OX40 as a marker of recently activated CD4 T cells at the infection site and a potential target for immunotherapy in tuberculosis.
Subject(s)
CD4-Positive T-Lymphocytes , Tuberculosis , Humans , Mice , Animals , Receptors, OX40/agonists , CD8-Positive T-Lymphocytes , Immunotherapy , Tuberculosis/therapyABSTRACT
Tuberculosis granuloma T cells express an array of mediators including the CD30 co-stimulatory receptor and its ligand, CD153. CD4 T effector cells require signals through CD30, potentially provided co-operatively by other T cells, to completely differentiate and protect against disease (Foreman et al., 2023. J. Exp. Med.https://doi.org/10.1084/jem.20222090).
Subject(s)
CD4-Positive T-Lymphocytes , Granuloma , HumansABSTRACT
The development of new tools to combat TB is counterbalanced by the discovery of previously unknown biological mechanisms used by M. tuberculosis to evade eradication. Two new studies offer both new hope, in a promising ribosome-targeting TB therapy, as well as a new challenge to overcome, in antibiotic resilience.
Subject(s)
Mycobacterium tuberculosis , Tuberculosis , Humans , Tuberculosis/drug therapy , Antitubercular Agents/pharmacology , Antitubercular Agents/therapeutic useABSTRACT
Atherosclerosis is driven by the expansion of cholesterol-loaded 'foamy' macrophages in the arterial intima. Factors regulating foamy macrophage differentiation and survival in plaque remain poorly understood. Here we show, using trajectory analysis of integrated single-cell RNA sequencing data and a genome-wide CRISPR screen, that triggering receptor expressed on myeloid cells 2 (Trem2) is associated with foamy macrophage specification. Loss of Trem2 led to a reduced ability of foamy macrophages to take up oxidized low-density lipoprotein (oxLDL). Myeloid-specific deletion of Trem2 showed an attenuation of plaque progression, even when targeted in established atherosclerotic lesions, and was independent of changes in circulating cytokines, monocyte recruitment or cholesterol levels. Mechanistically, we link Trem2-deficient macrophages with a failure to upregulate cholesterol efflux molecules, resulting in impaired proliferation and survival. Overall, we identify Trem2 as a regulator of foamy macrophage differentiation and atherosclerotic plaque growth and as a putative therapeutic target for atherosclerosis.
ABSTRACT
Immunosuppressed patients with inflammatory bowel disease (IBD) generate lower amounts of SARS-CoV-2 spike antibodies after mRNA vaccination than healthy controls. We assessed SARS-CoV-2 spike S1 receptor binding domain-specific (S1-RBD-specific) B lymphocytes to identify the underlying cellular defects. Patients with IBD produced fewer anti-S1-RBD antibody-secreting B cells than controls after the first mRNA vaccination and lower amounts of total and neutralizing antibodies after the second. S1-RBD-specific memory B cells were generated to the same degree in IBD and control groups and were numerically stable for 5 months. However, the memory B cells in patients with IBD had a lower S1-RBD-binding capacity than those in controls, which is indicative of a defect in antibody affinity maturation. Administration of a third shot to patients with IBD elevated serum antibodies and generated memory B cells with a normal antigen-binding capacity. These results show that patients with IBD have defects in the formation of antibody-secreting B cells and affinity-matured memory B cells that are corrected by a third vaccination.
Subject(s)
COVID-19 , Inflammatory Bowel Diseases , Antibodies, Viral , COVID-19/prevention & control , Humans , Memory B Cells , RNA, Messenger , SARS-CoV-2 , Spike Glycoprotein, CoronavirusABSTRACT
Deja vu is the sensation of having a recurrent experience. Within a year after an initial urinary tract infection (UTI), up to 30% of women will experience a recurrence of UTI symptoms.1 A smaller group of women (1%) may experience frequent recurrence with six or more episodes in a year. Recurrent UTI, or "deja vUTI," is a challenging problem that still lacks a cohesive pathophysiological mechanism, and it is currently addressed with a wide range of clinical practices often based on experience rather than on high-quality evidence.
ABSTRACT
How Do I Navigate Latent Tuberculosis Diagnosis?Tuberculosis (TB) is one of the most common infectious causes of death worldwide. Latent TB infection is a state of quiescent, clinically asymptomatic, noncontagious, chronic infection with the bacterial pathogen Mycobacterium tuberculosis. Diagnosing latent TB infection is often difficult. This Curbside Consult explores the common question: How do I navigate latent tuberculosis diagnosis?
Subject(s)
Latent Tuberculosis , Mycobacterium tuberculosis , Tuberculosis , Humans , Latent Tuberculosis/diagnosisABSTRACT
Single-domain Variable New Antigen Receptors (VNARs) from the immune system of sharks are the smallest naturally occurring binding domains found in nature. Possessing flexible paratopes that can recognize protein motifs inaccessible to classical antibodies, VNARs have yet to be exploited for the development of SARS-CoV-2 therapeutics. Here, we detail the identification of a series of VNARs from a VNAR phage display library screened against the SARS-CoV-2 receptor binding domain (RBD). The ability of the VNARs to neutralize pseudotype and authentic live SARS-CoV-2 virus rivalled or exceeded that of full-length immunoglobulins and other single-domain antibodies. Crystallographic analysis of two VNARs found that they recognized separate epitopes on the RBD and had distinctly different mechanisms of virus neutralization unique to VNARs. Structural and biochemical data suggest that VNARs would be effective therapeutic agents against emerging SARS-CoV-2 mutants, including the Delta variant, and coronaviruses across multiple phylogenetic lineages. This study highlights the utility of VNARs as effective therapeutics against coronaviruses and may serve as a critical milestone for nearing a paradigm shift of the greater biologic landscape.
Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Crystallography, X-Ray , Receptors, Antigen/chemistry , Receptors, Antigen/immunology , Sharks/immunology , Angiotensin-Converting Enzyme 2 , Animals , COVID-19 , Epitopes , Mutation , Phylogeny , Protein Binding , SARS-CoV-2 , Sequence Alignment , Single-Domain Antibodies , Spike Glycoprotein, Coronavirus/immunologyABSTRACT
BACKGROUND: The SARS-CoV-2 virus enters cells via Angiotensin-converting enzyme 2 (ACE2), disrupting the renin-angiotensin-aldosterone axis, potentially contributing to lung injury. Treatment with angiotensin receptor blockers (ARBs), such as losartan, may mitigate these effects, though induction of ACE2 could increase viral entry, replication, and worsen disease. METHODS: This study represents a placebo-controlled blinded randomized clinical trial (RCT) to test the efficacy of losartan on outpatients with COVID-19 across three hospital systems with numerous community sites in Minnesota, U.S. Participants included symptomatic outpatients with COVID-19 not already taking ACE-inhibitors or ARBs, enrolled within 7 days of symptom onset. Patients were randomized to 1:1 losartan (25 mg orally twice daily unless estimated glomerular filtration rate, eGFR, was reduced, when dosing was reduced to once daily) versus placebo for 10 days, and all patients and outcome assesors were blinded. The primary outcome was all-cause hospitalization within 15 days. Secondary outcomes included functional status, dyspnea, temperature, and viral load. (clinicatrials.gov, NCT04311177, closed to new participants). FINDINGS: From April to November 2020, 117 participants were randomized 58 to losartan and 59 to placebo, and all were analyzed under intent to treat principles. The primary outcome did not differ significantly between the two arms based on Barnard's test [losartan arm: 3 events (5.2% 95% CI 1.1, 14.4%) versus placebo arm: 1 event (1.7%; 95% CI 0.0, 9.1%)]; proportion difference -3.5% (95% CI -13.2, 4.8%); p = 0.32]. Viral loads were not statistically different between treatment groups at any time point. Adverse events per 10 patient days did not differ signifcantly [0.33 (95% CI 0.22-0.49) for losartan vs. 0.37 (95% CI 0.25-0.55) for placebo]. Due to a lower than expected hospitalization rate and low likelihood of a clinically important treatment effect, the trial was terminated early. INTERPRETATION: In this multicenter blinded RCT for outpatients with mild symptomatic COVID-19 disease, losartan did not reduce hospitalizations, though assessment was limited by low event rate. Importantly, viral load was not statistically affected by treatment. This study does not support initiation of losartan for low-risk outpatients.
ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. Neutralizing Abs target the receptor binding domain of the spike (S) protein, a focus of successful vaccine efforts. Concerns have arisen that S-specific vaccine immunity may fail to neutralize emerging variants. We show that vaccination with a human adenovirus type 5 vector expressing the SARS-CoV-2 nucleocapsid (N) protein can establish protective immunity, defined by reduced weight loss and viral load, in both Syrian hamsters and K18-hACE2 mice. Challenge of vaccinated mice was associated with rapid N-specific T cell recall responses in the respiratory mucosa. This study supports the rationale for including additional viral Ags in SARS-CoV-2 vaccines, even if they are not a target of neutralizing Abs, to broaden epitope coverage and immune effector mechanisms.
Subject(s)
Antibodies, Viral/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Neutralizing/immunology , COVID-19/immunology , Cell Line , Chlorocebus aethiops , Cricetinae , Female , Immunologic Memory/immunology , Lymphocyte Count , Male , Mice , Mice, Inbred C57BL , Phosphoproteins/immunology , Vaccination , Vero CellsABSTRACT
As some of those who were lucky enough to have been mentored by Dr Francisco Marty in transplant infectious diseases, we stand with the larger medical community in mourning his untimely death and in commemorating him as a uniquely exceptional and talented physician, investigator, teacher, mentor, friend, artist, and human being.
Subject(s)
Physicians , Humans , MaleABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. Neutralizing antibodies target the receptor binding domain of the spike (S) protein, a focus of successful vaccine efforts. Concerns have arisen that S-specific vaccine immunity may fail to neutralize emerging variants. We show that vaccination with HAd5 expressing the nucleocapsid (N) protein can establish protective immunity, defined by reduced weight loss and viral load, in both Syrian hamsters and k18-hACE2 mice. Challenge of vaccinated mice was associated with rapid N-specific T cell recall responses in the respiratory mucosa. This study supports the rationale for including additional viral antigens, even if they are not a target of neutralizing antibodies, to broaden epitope coverage and immune effector mechanisms.
ABSTRACT
Invasive fungal disease (IFD) can be a severe treatment complication in patients with myeloid malignancies, but current risk models do not incorporate disease-specific factors, such as somatic gene mutations. Germline GATA2 deficiency is associated with a susceptibility to IFD. To determine whether myeloid gene mutations were associated with IFD risk, we identified 2 complementary cohorts of patients with myeloid malignancy, based on (1) the diagnosis of invasive aspergillosis (IA), or (2) the presence of GATA2 mutations identified during standard clinical sequencing. We found somatic GATA2 mutations in 5 of 27 consecutive patients who had myeloid malignancy and developed IA. Among 51 consecutive patients with GATA2 mutations identified in the evaluation of myeloid malignancy, we found that IFD was diagnosed and treated in 21 (41%), all of whom had received chemotherapy or had undergone an allogeneic stem cell transplant. Pulmonary infections and disseminated candidiasis were most common. The 90-day mortality was 52% among patients with IFD. Our results indicate that patients with somatic GATA2 mutations are a vulnerable subgroup of patients with myeloid malignancy who have high risk for treatment-associated IFD and suggest that a focused approach to antifungal prophylaxis be considered.
Subject(s)
Candidiasis , Invasive Fungal Infections , Neoplasms , Antifungal Agents/therapeutic use , Candidiasis/drug therapy , GATA2 Transcription Factor/genetics , Humans , Invasive Fungal Infections/drug therapy , Mutation , Neoplasms/drug therapyABSTRACT
OBJECTIVES: To avoid the significant risks posed by the use of COVID-19 serology tests with supply chain constraints or poor performance characteristics, we developed an in-house SARS-CoV-2 total antibody test. Our test was compared with three commercial methods, and was used to determine COVID-19 seroprevalence among healthcare workers and outpatients in Minnesota. METHODS: Seventy-nine plasma and serum samples from 50 patients 4-69 days after symptom onset who tested positive by a SARS-CoV-2 PCR method using a nasopharyngeal (NP) swab were used to evaluate our test's clinical performance. Seropositive samples were analyzed for IgG titers in a follow-up assay. Thirty plasma and serum from 12 patients who tested negative by a SARS-CoV-2 PCR method using a nasopharyngeal (NP) swab and 210 negative pre-pandemic serum samples were also analyzed. Among samples from patients > 14 days after symptom onset, the assay had 100% clinical sensitivity and 100% clinical specificity, 100% positive predictive value and 100% negative predictive value. Analytical specificity was 99.8%, indicating minimal cross-reactivity. A screening study was conducted to ascertain COVID-19 seroprevalence among healthcare workers and outpatients in Minnesota. RESULTS: Analysis of serum collected between April 13 and May 21, 2020 indicated a COVID-19 seroprevalence of 2.96% among 1,282 healthcare workers and 4.46% among 2,379 outpatients. CONCLUSIONS: Our in-house SARS-CoV-2 total antibody test can be used to conduct reliable epidemiological studies to inform public health decisions during the COVID-19 pandemic.
Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , COVID-19/epidemiology , Health Personnel , Outpatients , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Viral/blood , COVID-19/immunology , Child , Child, Preschool , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin G/blood , Infant , Male , Middle Aged , Minnesota/epidemiology , SARS-CoV-2/isolation & purification , Seroepidemiologic Studies , Young AdultABSTRACT
The human airway epithelium is the initial site of SARS-CoV-2 infection. We used flow cytometry and single cell RNA-sequencing to understand how the heterogeneity of this diverse cell population contributes to elements of viral tropism and pathogenesis, antiviral immunity, and treatment response to remdesivir. We found that, while a variety of epithelial cell types are susceptible to infection, ciliated cells are the predominant cell target of SARS-CoV-2. The host protease TMPRSS2 was required for infection of these cells. Importantly, remdesivir treatment effectively inhibited viral replication across cell types, and blunted hyperinflammatory responses. Induction of interferon responses within infected cells was rare and there was significant heterogeneity in the antiviral gene signatures, varying with the burden of infection in each cell. We also found that heavily infected secretory cells expressed abundant IL-6, a potential mediator of COVID-19 pathogenesis.
Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , COVID-19/immunology , COVID-19/virology , SARS-CoV-2/physiology , Viral Tropism , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , COVID-19/genetics , Epithelium/immunology , Epithelium/virology , Humans , Interferons/genetics , Interferons/immunology , Interleukin-6/genetics , Interleukin-6/immunology , Lung/immunology , Lung/virology , SARS-CoV-2/drug effects , Viral Tropism/drug effects , Virus Replication/drug effects , COVID-19 Drug TreatmentABSTRACT
The magnitude of SARS-CoV-2-specific T cell responses correlates inversely with human disease severity, suggesting T cell involvement in primary control. Whereas many COVID-19 vaccines focus on establishing humoral immunity to viral spike protein, vaccine-elicited T cell immunity may bolster durable protection or cross-reactivity with viral variants. To better enable mechanistic and vaccination studies in mice, we identified a dominant CD8 T cell SARS-CoV-2 nucleoprotein epitope. Infection of human ACE2 transgenic mice with SARS-CoV-2 elicited robust responses to H2-Db/N219-227, and 40% of HLA-A*02+ COVID-19 PBMC samples isolated from hospitalized patients responded to this peptide in culture. In mice, i.m. prime-boost nucleoprotein vaccination with heterologous vectors favored systemic CD8 T cell responses, whereas intranasal boosting favored respiratory immunity. In contrast, a single i.v. immunization with recombinant adenovirus established robust CD8 T cell memory both systemically and in the respiratory mucosa.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , COVID-19/prevention & control , Epitopes, T-Lymphocyte/immunology , SARS-CoV-2/immunology , Vaccination/methods , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/virology , Cells, Cultured , Coronavirus Nucleocapsid Proteins/immunology , Disease Models, Animal , Female , Genetic Vectors/immunology , HLA-A2 Antigen/immunology , Humans , Mice , Mice, Inbred C57BL , Mice, TransgenicABSTRACT
Coronavirus disease 2019 (COVID-19) outcomes are linked to host immune responses and may be affected by antiviral therapy. We investigated antibody and cytokine responses in ACTT-1 study participants enrolled at our center. We studied serum specimens from 19 hospitalized adults with COVID-19 randomized to treatment with remdesivir or placebo. We assessed severe acute respiratory syndrome coronavirus 2 antibody responses and identified cytokine signatures, using hierarchical clustering. We identified no clear immunologic trends attributable to remdesivir treatment. Seven participants were initially seronegative at study enrollment, and all 4 deaths occurred in this group with more recent symptom onset. We identified 3 dominant cytokine signatures, demonstrating different disease trajectories.
Subject(s)
COVID-19/immunology , COVID-19/mortality , Immunity/immunology , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/immunology , Adenosine Monophosphate/therapeutic use , Adult , Alanine/analogs & derivatives , Alanine/immunology , Alanine/therapeutic use , Antibodies, Viral/immunology , Antiviral Agents/immunology , Antiviral Agents/therapeutic use , COVID-19/virology , Cytokines/immunology , Female , Humans , Immunity/drug effects , Male , SARS-CoV-2/drug effects , SARS-CoV-2/immunology , COVID-19 Drug TreatmentABSTRACT
Background: During the coronavirus disease 2019 (COVID-19) pandemic, clinical trials necessitated rapid testing to be performed remotely. Dried blood spot (DBS) techniques have enabled remote HIV virologic testing globally, and more recently, antibody testing as well. We evaluated DBS testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody testing in outpatients to assess seropositivity. Methods: In 2020, we conducted 3 internet-based randomized clinical trials and offered serologic testing via self-collected DBS as a voluntary substudy. COVID-19 diagnosis was based on the Centers for Disease Control and Prevention case definition with epidemiological link to cases. A minority reported polymerase chain reaction (PCR) testing at an outside facility. We tested for anti-SARS-CoV-2 immunoglobulin via antibody detection by agglutination-PCR (ADAP) and compared the results with enzyme-linked immunosorbent assay (ELISA). Results: Of 2727 participants in the primary studies, 60% (1648/2727) consented for serology testing; 56% (931/1648) returned a usable DBS sample. Of those who were asymptomatic, 5% (33/707) had positive ADAP serology. Of participants with a positive PCR, 67% (36/54) had positive SARS-CoV-2 antibodies. None of those who were PCR-positive and asymptomatic were seropositive (0/7). Of 77 specimens tested for concordance via ELISA, 83% (64/77) were concordant. The challenges of completing a remote testing program during a pandemic included sourcing and assembling collection kits, delivery and return of the kits, and troubleshooting testing. Self-collection was successful for >95% of participants. Delays in US mail with possible sample degradation and timing of DBS collection complicated the analysis. Conclusions: We found remote antibody testing during a global pandemic feasible although challenging. We identified an association between symptomatic COVID-19 and positive antibody results at a similar prevalence as other outpatient cohorts.
ABSTRACT
BACKGROUND: The transfer of passive immunity with convalescent plasma is a promising strategy for treatment and prevention of COVID-19, but donors with a history of nonsevere disease are serologically heterogenous. The relationship between SARS-Cov-2 antigen-binding activity and neutralization activity in this population of donors has not been defined. STUDY DESIGN AND METHODS: Convalescent plasma units from 47 individuals with a history of nonsevere COVID-19 were assessed for antigen-binding activity of using three clinical diagnostic serology assays (Beckman, DiaSorin, and Roche) with different SARS-CoV-2 targets. These results were compared with functional neutralization activity using a fluorescent reporter strain of SARS-CoV-2 in a microwell assay. RESULTS: Positive correlations of varying strength (Spearman r = 0.37-0.52) between antigen binding and viral neutralization were identified. Donors age 48 to 75 years had the highest neutralization activity. Units in the highest tertile of binding activity for each assay were enriched (75%-82%) for those with the highest levels of neutralization. CONCLUSION: The strength of the relationship between antigen-binding activity and neutralization varies depending on the clinical assay used. Units in the highest tertile of binding activity for each assay are predominantly comprised of those with the greatest neutralization activity.