ETIDIOH - NEW

  Abstract As intrinsic differences in humoral immune response to SARS-CoV-2 between children and adults remain unclear , we improved characterisation by defining the kinetics, specificity and function of antibodies to SARS-CoV-2 in children (n = 146, aged 9.4 ± 4.8 years with n = 257 samples) compared to adults (n = 85, aged 39.5 ± 15.2 years with n = 122 samples). We used plasma samples from an infection and vaccination-naive cohort study with RT-PCR confirmed ancestral B.1* SARS-CoV-2 virus infection with asymptomatic or mild disease, collected in Hong Kong between March to December 2020, from acute (0–14 days post infection) to convalescent (15–206 days) timepoints. Children had significantly lower primary antibody responses against SARS-CoV-2 proteins overall, leading to a less isotype switched response. While children had lower OC43 Spike and SARS-CoV-2 S2 IgG and avidity than adults, they exhibited higher avidities for SARS-CoV-2 whole Spike and Nucleocapsid , and higher lev...

  By Matthew Black - originally posted to Flickr as DPP_0612, CC BY-SA 2.0,  https://commons.wikimedia.org/w/index.php?curid=7171062 Source: Wikipedia,  https://en.wikipedia.org/wiki/DB_Class_V_200 ____

  Abstract COVID-19 and long COVID are characterized by a dysregulated immune response. However, the role of macrophages during viral infection is poorly defined. Here we demonstrate that SARS-CoV-2 infection results in increased macrophage numbers and extensive formation of enlarged lipid-laden macrophages or foam cells using humanized mice , rhesus macaques and post-mortem human lung tissue . Notably, infection by other coronaviruses tested, SARS-CoV-1, MERS-CoV and two bat coronaviruses (SHC014-CoV or WIV1-CoV), did not result in macrophage proliferation or foam cell formation. Foam cells in SARS-CoV-2-infected human lung tissue display a pro-fibrotic and pro-thrombotic phenotype as they are enriched for genes associated with platelet activation and aggregation , as well as extracellular matrix organization and collagen synthesis . After viral clearance, macrophage numbers remain elevated, and lung fibrosis and thrombi persist . Importantly, we show that pre-exposure prophylaxis...