2) The study investigated how previous vaccination with mRNA vaccines targeting the original Wuhan strain of SARS-CoV-2 affects the immune response to infection with the Omicron variant.
3) Three groups of individuals were studied: 1) unvaccinated individuals infected with Omicron, 2) individuals vaccinated 3 times who were later infected with Omicron, 3) individuals vaccinated 3 times but uninfected.
4) Vaccination increased plasma antibodies and neutralizing antibodies against Omicron, but it impaired the generation of new antibodies and B cells targeting mutated regions of the Omicron spike protein compared to unvaccinated infected individuals.
5) T cell responses to mutated regions of the Omicron spike protein were similar between vaccinated infected/uninfected individuals and unvaccinated infected individuals, likely due to higher cross-reactivity of T cells.
6) The findings suggest vaccination imprints the immune response and hinders the formation of antibodies and B cells targeting variants that have mutated sufficiently from the original strain.
7) This antigenic imprinting effect of vaccination could lead to a phenomenon called "original antigenic sin", whereby immunity fails to control a highly mutated variant that escapes existing vaccine-induced immunity.
8) The study highlights the importance of developing variant-adapted vaccines that can induce immune responses targeting both conserved and mutated regions of emerging variants.
2) The SARS-CoV-2 envelope protein E is the smallest structural protein but its role in viral invasion, replication and release is not fully understood. It is known to form ion channels and alter calcium homeostasis.
3) Previous structural models of E based on NMR data showed a pentameric assembly that collapsed in simulations, without forming a stable water pore.
New molecular dynamics simulations proposed an alternative pentameric model (Model B) where helices are oriented oppositely ...
"New research has uncovered a social world of viruses full of cheating, cooperation and other intrigues ... quantamagazine.org/viruses-finallโฆ
2) ...suggesting that viruses make sense only as members of a community."
Traditionally, viruses were thought of as solitary particles that could only replicate by infecting cells. But recent research shows viruses have complex social behaviors.
3) A new field called "sociovirology" studies the social lives of viruses, including cheating, cooperation and other interactions between viruses.
Viruses don't have social lives like humans or other species, but they do engage in social behaviors within cells and hosts.
2) Post-acute sequelae of SARS-CoV-2 infection (PASC), also known as long COVID, refers to symptoms that persist beyond 12 weeks after initial infection. PASC can affect multiple organ systems including respiratory, cardiovascular, neurological, psychiatric, urinary, blood, skin
3) ...and digestive systems. Common symptoms include fatigue, headache, cough, loss of smell/taste, muscle pain.
The pathophysiology of PASC is complex and multi-factorial. Potential mechanisms include direct virus-mediated damage, immune system dysregulation/autoimmunity,
Microgliosis and astrogliosis describe the morphological and functional activation of microglia and astrocytes that biorxiv.org/content/10.110โฆ
2) ...occurs as part of the neuroinflammatory response to various CNS insults or perturbations.
This study examined brain tissue from 12 COVID-19 patients and 10 non-COVID controls to investigate the effects of SARS-CoV-2 infection on astrocytes and microglia.
3) Microgliosis (activated microglia) was observed in the frontal cortex of 11/12 COVID-19 patients, as shown by retracted processes and enlarged cell bodies when stained for Iba1. Only 1/10 controls showed microgliosis.
Astrocytes in the gray matter of 10/12 COVID-19 patients
The researchers developed an ex vivo model of SARS-CoV-2 infection in human lung slices to study virus-host interactions at single-cell resolution. This allowed them to measure viral tropism and infection dynamics in native lung tissue.
3) Single-cell RNA sequencing revealed that SARS-CoV-2 preferentially infects activated interstitial macrophages (a-IMs) in the human lung. a-IMs accounted for the majority of cells harboring high viral loads.
2) The study investigated the prevalence, predictors and prognostic implications of myocardial injury in elderly patients (ages 65+) hospitalized with COVID-19 infection.
A total of 347 patients were included in the analysis. 58.2% had evidence of myocardial injury based ...
3) ...on elevated high-sensitivity cardiac troponin T levels.
Older age, hypertension, higher creatinine levels, and higher neutrophil-to-lymphocyte ratio were independent risk factors for myocardial injury. Vaccination was protective.