Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.21.213777v1?rss=1 Authors: Fahlberg, M. D., Blair, R. V., Doyle-Meyers, L. A., Midkiff, C. C., Zenere, G., Russell-Lodrigue, K. E., Monjure, C. J., Haupt, E. H., Penney, T. P., Lehmicke, G., Threeton, B. M., Golden, N., Datta, P. K., Roy, C. J., Bohm, R. P., Maness, N. J., Fischer, T., Rappaport, J., Vaccari, M. Abstract: We investigated the immune events following SARS-COV-2 infection, from the acute inflammatory state up to four weeks post infection, in non-human primates (NHP) with heterogeneous pulmonary pathology. The acute phase was characterized by a rapid migration of CD16+ monocytes from the blood and concomitant increase in CD16+ macrophages in the lungs. We identified two subsets of interstitial macrophages (HLA- DR+ CD206-), a transitional CD11c+ CD16+ population that was directly associated with IL-6 levels in plasma, and one long lasting CD11b+ CD16+ population. Strikingly, monocytes were a correlate of viral replication in bronchial brushes and levels of TARC (CCL17), and worse disease outcomes were associated with high levels of cell infiltration in lungs and CD11b+ CD16+ macrophages accumulation. Importantly, this accumulation was long-lasting and detectable even in animals with mild or no signs of disease. Interestingly, animals with less signs of disease had a high IL-10:IL-6 ratio. Our results unravel cellular mechanisms of COVID-19 and validate NHP as models to test immune therapies. Copy rights belong to original authors. Visit the link for more info