A Large Repertoire of B Cell Lineages Targeting One Cluster of Epitopes in a Vaccinated Rhesus Macaque
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A rhesus macaque that was serially immunized six times with the 8-mer epitope for human monoclonal antibody (mAb) 447-52D—specific to the V3 region of gp120 HIV-1—provided a rare opportunity to study the repertoire of antibodies produced upon vaccination against a particular antigenic site. From a blood sample taken 3 weeks after the last immunization, researchers produced 41 V3-specific recombinant mAbs by single B cell isolation and cloning. Sequence analysis revealed 21 B cell lineages (single and clonally related).
Blocking α4β7 Integrin Delays Viral Rebound in SHIVSF162P3-Infected Macaques Treated with Anti-HIV Broadly Neutralizing Antibodies
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To explore therapeutic potentials of combining anti-HIV broadly neutralizing antibodies (bNAbs) with α4β7 integrin blockade using the monoclonal antibody Rh-α4β7, investigators treated SHIVSF162P3-infected, viremic macaques with bNAbs only or bNAbs and Rh-α4β7. Treatment with bNAbs alone decreased viremia below 200 copies/ml in eight out of eight macaques, but seven of the monkeys rebounded within 3 weeks. In contrast, three of six macaques treated with both Rh-α4β7 and bNAbs maintained viremia below 200 copies/ml for 21 weeks, whereas three of those monkeys rebounded after 6 weeks.
Protection of Newborn Macaques by Plant-Derived HIV Broadly Neutralizing Antibodies: A Model for Passive Immunotherapy During Breastfeeding
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Preventing vertical transmission of HIV to newborns is an unmet medical need in resource poor countries. Using a breastfeeding macaque model with multiple simian-human immunodeficiency virus challenge, researchers assessed the protective efficacy of two human broadly neutralizing antibodies (bnAbs) against HIV, PGT121 and VRC07-523, which are produced by a plant expression system.
In Vitro and In Vivo Functions of SARS-CoV-2 Infection-Enhancing and Neutralizing Antibodies
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Antibody-dependent enhancement of infection is a concern for clinical use of antibodies. Researchers isolated neutralizing antibodies against the receptor-binding domain (RBD) or N-terminal domain (NTD) of SARS-CoV-2 spike from COVID-19 patients. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific binding modes. RBD and NTD antibodies mediated both neutralization and infection enhancement in vitro.
Neutralizing Antibody Vaccine for Pandemic and Pre-Emergent Coronaviruses
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SARS-CoV-2 is a new member of the betacoronavirus (beta-CoV) genus, which also includes two common mild beta-CoVs and the life-threatening SARS-CoV-1 and MERS-CoV. Vaccines that elicit protective immunity against SARS-CoV-2 and beta-CoVs that circulate in animals could prevent future pandemics. Researchers designed a novel 24-mer SARS-CoV-2 receptor binding domain-sortase A conjugated nanoparticle vaccine (RBD-scNP).
Mineralocorticoid Receptor Blockade Normalizes Coronary Resistance in Obese Swine Independent of Functional Alterations in Kv Channels
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Impaired coronary microvascular function (e.g., reduced dilation and coronary flow reserve) predicts cardiac mortality in obesity. Mineralocorticoid receptor (MR) antagonism improves coronary microvascular function in obese humans and animals. Inhibition of Kv channels reduced coronary blood flow and augmented coronary resistance under baseline conditions in lean but not obese swine and had no impact on hypoxemic coronary vasodilation. MR blockade prevented obesity-associated coronary arteriolar stiffening independent of cardiac capillary density and changes in cardiac function.
Tract Pathogen-Mediated Inflammation Through Development of Multimodal Treatment Regimen and Its Impact on SIV Acquisition in Rhesus Macaques
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In addition to being premier HIV models, rhesus macaques are models for other infectious diseases and colitis, where background colon health and inflammation may confound results. Starting with the standard specific-pathogen-free (SPF) model, researchers established a gastrointestinal pathogen-free (GPF) colony via multimodal therapy (enrofloxacin, azithromycin, fenbendazole, and paromomycin) to eliminate common endemic pathogens (EPs).
Psychosocial Stress Alters the Immune Response and Results in Higher Viral Load During Acute SIV Infection in a Pigtailed Macaque Model of HIV
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Social distancing is an important countermeasure for a pandemic, but social isolation may also have adverse health outcomes in the context of infectious diseases, such as HIV. Researchers compared commonly measured parameters of HIV progression between singly and socially housed simian immunodeficiency virus (SIV)-infected pigtailed macaques.
Combining In Vivo Corneal Confocal Microscopy With Deep Learning-Based Analysis Reveals Sensory Nerve Fiber Loss in Acute Simian Immunodeficiency Virus Infection
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Researchers characterized corneal subbasal nerve plexus features of normal and simian immunodeficiency virus (SIV)-infected pigtail and rhesus macaques using in vivo confocal microscopy and a deep learning approach for automated assessments. Corneal nerve fiber length and fractal dimension measurements did not differ between species, but pigtail macaques had significantly higher baseline corneal nerve fiber tortuosity than rhesus macaques. Acute SIV infection induced decreased corneal nerve fiber length and fractal dimension in the pigtail macaque model for HIV.
Modulation of MHC-E Transport by Viral Decoy Ligands Is Required for RhCMV/SIV Vaccine Efficacy
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Rhesus cytomegalovirus (RhCMV) strain 68-1-vectored simian immunodeficiency virus (SIV) vaccines elicit strong CD8+ T cell responses that can clear SIV infections. Peptides targeted by these T cells are presented on major histocompatibility complex (MHC) II and MHC-E rather than MHC-Ia. Researchers showed that VL9 drives intracellular transport of MHC-E and recognition of RhCMV-infected targets by MHC-E-restricted CD8+ T cells.