ABSTRACT
The baseline composition of T cells directly affects later response to pathogens, but the complexity of precursor states remains poorly defined. Here, we examined the baseline state of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cells in unexposed individuals. SARS-CoV-2-specific CD4+ T cells were identified in prepandemic blood samples by major histocompatibility complex (MHC) class II tetramer staining and enrichment. Our data revealed a substantial number of SARS-CoV-2-specific T cells that expressed memory phenotype markers. Integrated phenotypic analyses demonstrated diverse preexisting memory states that included cells with distinct polarization features and trafficking potential to barrier tissues. T cell clones generated from tetramer-labeled cells cross-reacted with antigens from commensal bacteria in the skin and gastrointestinal tract. Direct ex vivo tetramer staining for one spike-specific population showed a similar level of cross-reactivity to sequences from endemic coronavirus and commensal bacteria. These data highlight the complexity of precursor T cell repertoire and implicate noninfectious exposures to common microbes as a key factor that shapes human preexisting immunity to SARS-CoV-2.
Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Humans , Immunologic Memory , Spike Glycoprotein, Coronavirus , T-LymphocytesABSTRACT
The coronavirus pandemic upended everything. In addition to the pandemic, widespread street demonstrations protested systemic racism and pervasive police violence against Blacks. To document this history-making year, the State Archives of North Carolina and the North Carolina Museum of History partnered to launch a rapid response collection called Your Story is North Carolina's Story. The story project cast a wide net to gather first-person accounts through journal writings, photographs, objets d'art, oral reminiscences, yard signs, and other artifacts that reflect the zeitgeist of the times. Here, Williams shares the story she contributed monthly to the story collection from April through the end of the year. She titled the submissions "My Coronavirus World: A Diary."