Publications by authors named "Dennis Hartigan-O Connor"

Feline infectious peritonitis (FIP) is a devastating and often fatal disease caused by feline coronavirus (FCoV). Currently, there is no widely used vaccine for FIP, and many attempts using a variety of platforms have been largely unsuccessful due to the disease's highly complicated pathogenesis. One such complication is antibody-dependent enhancement (ADE) seen in FIP, which occurs when sub-neutralizing antibody responses to viral proteins paradoxically enhance disease.

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Gene editing strategies for cystic fibrosis are challenged by the complex barrier properties of airway epithelia. We previously reported that the amphiphilic S10 shuttle peptide non-covalently combined with CRISPR-associated (Cas) ribonucleoprotein (RNP) enabled editing of human and mouse airway epithelial cells. Here, we derive the S315 peptide as an improvement over S10 in delivering base editor RNP.

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We assessed the humoral immune responses to a COVID-19 vaccine in a well-controlled rhesus macaque model compared to humans immunized with two mRNA vaccines over several months post-second dose. The plasma IgG levels against seven coronaviruses (including SARS-CoV-2) and antibody subtypes (IgG 1-4 and IgM) against SARS-CoV-2 were evaluated using multiplex assays. The neutralization capacity of plasma antibodies against the original SAR-CoV-2 isolate and nine variants was evaluated in vaccinated humans and non-human primates.

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"Adaptive" NK cells, characterized by FcRγ deficiency and enhanced responsiveness to Ab-bound, virus-infected cells, have been found in certain hCMV-seropositive individuals. Because humans are exposed to numerous microbes and environmental agents, specific relationships between hCMV and FcRγ-deficient NK cells (also known as g-NK cells) have been challenging to define. Here, we show that a subgroup of rhesus CMV (RhCMV)-seropositive macaques possesses FcRγ-deficient NK cells that stably persist and display a phenotype resembling human FcRγ-deficient NK cells.

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Transplantation of allogeneic donor ovarian tissue holds great potential for female cancer survivors who often experience premature ovarian insufficiency. To avoid complications associated with immune suppression and to protect transplanted ovarian allografts from immune-mediated injury, we have developed an immunoisolating hydrogel-based capsule that supports the function of ovarian allografts without triggering an immune response. Encapsulated ovarian allografts implanted in naïve ovariectomized BALB/c mice responded to the circulating gonadotropins and maintained function for 4 months, as evident by regular estrous cycles and the presence of antral follicles in the retrieved grafts.

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Treatment of people with HIV (PWH) with antiretroviral therapy (ART) results in sustained suppression of viremia, but HIV persists indefinitely as integrated provirus in CD4-expressing cells. Intact persistent provirus, the "rebound competent viral reservoir" (RCVR), is the primary obstacle to achieving a cure. Most variants of HIV enter CD4 T cells by binding to the chemokine receptor, CCR5.

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The implementation and access to combined antiretroviral treatment (cART) have dramatically improved the quality of life of people living with HIV (PLWH). However, some comorbidities, such as neurological disorders associated with HIV infection still represent a serious clinical challenge. Soluble factors in plasma that are associated with control of HIV replication and neurological dysfunction could serve as early biomarkers and as new therapeutic targets for this comorbidity.

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The contribution of the HLA-E/NKG2X axis in NK-mediated control of HIV infection remains unclear. We have studied the relationship between HLA-E expression and phenotypical as well as functional characteristics of NK cells, in the context of chronic HIV infection and in an model of acute infection. High viremia in HIV+ individuals was related to increased HLA-E expression, and changes in NK subpopulations, especially a reduction of the CD56 as well as an increase in adaptive NK subpopulation.

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Background: Both the gut microbiota and chronic viral infections have profound effects on host immunity, but interactions between these influences have been only superficially explored. Cytomegalovirus (CMV), for example, infects approximately 80% of people globally and drives significant changes in immune cells. Similarly, certain gut-resident bacteria affect T-cell development in mice and nonhuman primates.

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Purpose Of The Review: Not all T-cell responses against HIV are created equally and responses of certain epitope specificities have been associated with superior control of infection. These insights have spurred the development of a wide range of immunogen sequences, each with particular advantages and limitations.

Recent Findings: We review some of the most advanced designs that have reached or are close to reaching human clinical trials, with a special focus on T-cell immunogen developed for therapeutic use.

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T cell responses are considered critical for the control of HIV, but the contribution of different T cell subsets to this control remains unclear. Using a boosted flow cytometric approach that is able to differentiate CD4 and CD8 T cell Th1/Tc1, Th2/Tc2, Th17/Tc17, Treg and Tfh/Tfc-like HIV-specific T cell populations, we identified CD8 Tfc responses that were related to HIV plasma viral loads and associated with rate of antibody isotype class switching to IgG. This favorable balance towards IgG responses positively correlated with increased virus neutralization, higher avidity of neutralizing antibodies and more potent antibody-dependent cell cytotoxicity (ADCC) in PBMCs from HIV controllers compared to non-controllers.

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Although modern clinical practices such as cesarean sections and perinatal antibiotics have improved infant survival, treatment with broad-spectrum antibiotics alters intestinal microbiota and causes dysbiosis. Infants exposed to perinatal antibiotics have an increased likelihood of life-threatening infections, including pneumonia. Here, we investigated how the gut microbiota sculpt pulmonary immune responses, promoting recovery and resolution of infection in newborn rhesus macaques.

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Article Synopsis
  • - Early in the pandemic, there was hope that convalescent plasma from COVID-19 survivors would effectively treat hospitalized patients, but later controlled trials showed only moderate efficacy, especially when used early in infection.
  • - In a study, 12 adult rhesus macaques were infected with SARS-CoV-2 and then given either high-titer convalescent plasma or normal plasma; the results showed only slight benefits, with similar viral loads but reduced infectious virus in the lungs for those treated with convalescent plasma.
  • - Overall, the benefits of convalescent plasma were marginal compared to monoclonal antibodies, and the study highlights the need for improved animal models to test new treatment strategies against SARS-CoV-
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Article Synopsis
  • HIV-1 is a major global health problem due to reservoirs of dormant HIV in infected individuals that aren't eliminated by standard antiretroviral therapy.
  • The "Kick and Kill" strategy aims to activate these latent viruses using latency reversal agents (LRAs) like Protein Kinase C agonists (PKCa), which can disrupt dormant HIV despite concerns about their toxicity.
  • Resveratrol, a natural compound from grapes, shows promise in breaking HIV latency without triggering immune activation, suggesting it could be a safer option for targeting EGR1 to help eliminate HIV reservoirs.
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Idiopathic chronic diarrhea (ICD) is a little understood common clinical problem in captive rhesus macaques claiming 33% of medical culls unrelated to research. The eukaryotic virome in digestive tract tissues collected at necropsy from nine animals with ICD was characterized using viral metagenomics. We compared the distribution of viral reads in tissues and mucosal scrapings from the stomach, duodenum, jejunum, ileum, and the proximal, transverse, and distal colons.

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Article Synopsis
  • - The BCN02 trial explored the combination of therapeutic vaccination and romidepsin (a viral latency-reversing agent) in HIV-1-infected individuals, assessing viral rebound during a monitored antiretroviral pause to evaluate treatment efficacy.
  • - Researchers analyzed blood samples from 14 trial participants to determine differences between individuals who experienced early vs. late viral rebound, focusing on DNA methylation, chromatin states, and HIV-specific T-cell responses.
  • - Findings revealed distinct DNA methylation patterns that can help predict virus control after treatment, highlighting the potential of these epigenetic markers in developing effective HIV cure strategies.
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Nonhuman primates are essential for the study of human disease and to explore the safety of new diagnostics and therapies proposed for human use. They share similar genetic, physiologic, immunologic, reproductive, and developmental features with humans and thus have proven crucial for the study of embryonic/fetal development, organ system ontogeny, and the role of the maternal-placental-fetal interface in health and disease. The fetus may be exposed to a variety of inflammatory stimuli including infectious microbes as well as maternal inflammation, which can result from infections, obesity, or environmental exposures.

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Nonhuman primates are critically important animal models in which to study complex human diseases, understand biological functions, and address the safety of new diagnostics and therapies proposed for human use. They have genetic, physiologic, immunologic, and developmental similarities when compared to humans and therefore provide important preclinical models of human health and disease. This review highlights select research areas that demonstrate the importance of nonhuman primates in translational research.

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Childhood undernutrition is a major health burden worldwide that increases childhood morbidity and mortality and causes impairment in infant growth and developmental delays that can persist into adulthood. The first weeks and months after birth are critical to the establishment of healthy growth and development during childhood. The World Health Organization recommends immediate and exclusive breastfeeding (EBF).

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While recent changes in treatment have reduced the lethality of idiopathic chronic diarrhea (ICD), this condition remains one of the most common causes of rhesus macaque deaths in non-human primate research centers. We compared the viromes in fecal swabs from 52 animals with late stage ICD and 41 healthy animals. Viral metagenomics targeting virus-like particles was used to identify viruses fecally shed by each animal.

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Human clinical studies investigating use of convalescent plasma (CP) for treatment of coronavirus disease 2019 (COVID-19) have produced conflicting results. Outcomes in these studies may vary at least partly due to different timing of CP administration relative to symptom onset. The mechanisms of action of CP include neutralizing antibodies but may extend beyond virus neutralization to include normalization of blood clotting and dampening of inflammation.

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Anti-viral monoclonal antibody (mAb) treatments may provide immediate but short-term immunity from coronavirus disease 2019 (COVID-19) in high-risk populations, such as people with diabetes and the elderly; however, data on their efficacy in these populations are limited. We demonstrate that prophylactic mAb treatment blocks viral replication in both the upper and lower respiratory tracts in aged, type 2 diabetic rhesus macaques. mAb infusion dramatically curtails severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-mediated stimulation of interferon-induced chemokines and T cell activation, significantly reducing development of interstitial pneumonia.

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Unlabelled: Early in the SARS-CoV-2 pandemic, there was a high level of optimism based on observational studies and small controlled trials that treating hospitalized patients with convalescent plasma from COVID-19 survivors (CCP) would be an important immunotherapy. However, as more data from controlled trials became available, the results became disappointing, with at best moderate evidence of efficacy when CCP with high titers of neutralizing antibodies was used early in infection. To better understand the potential therapeutic efficacy of CCP, and to further validate SARS-CoV-2 infection of macaques as a reliable animal model for testing such strategies, we inoculated 12 adult rhesus macaques with SARS-CoV-2 by intratracheal and intranasal routes.

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COVID-19 serological test must have high sensitivity as well as specificity to rule out cross-reactivity with common coronaviruses (HCoVs). We have developed a quantitative multiplex test, measuring antibodies against spike (S) proteins of SARS-CoV-2, SARS-CoV, MERS-CoV, and common human coronavirus strains (229E, NL63, OC43, HKU1), and nucleocapsid (N) protein of SARS-CoV viruses. Receptor binding domain of S protein of SARS-CoV-2 (S-RBD), and N protein, demonstrated sensitivity (94% and 92.

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There is an urgent need for effective therapeutic interventions against SARS-CoV-2, including new variants that continue to arise. Neutralizing monoclonal antibodies have shown promise in clinical studies. We investigated the therapeutic efficacy of a combination of two potent monoclonal antibodies, C135-LS and C144-LS that carry half-life extension mutations, in the rhesus macaque model of COVID-19.

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