Recovery from Acute SARS-CoV-2 Infection and Development of Anamnestic Immune Responses in T Cell-Depleted Rhesus Macaques
Kim J. Hasenkrug, Friederike Feldmann, Lara Myers, Mario L. Santiago, Kejun Guo, Bradley S. Barrett, Kaylee L. Mickens, Aaron Carmody, Atsushi Okumura, Deepashri Rao, Madison M. Collins, Ronald J. Messer, Jamie Lovaglio, Carl Shaia, Rebecca Rosenke, Neeltje van Doremalen, Chad S. Clancy, Greg Saturday, Patrick W. Hanley, Brian J. Smith, Kimberly Meade‐White, W. Lesley Shupert, David W. Hawman, Heinz Feldmann
Abstract
Patients with severe COVID-19 often have decreased numbers of T cells, a cell type important in fighting most viral infections. However, it is not known whether the loss of T cells contributes to severe COVID-19 or is a consequence of it. We studied rhesus macaques, which develop only mild COVID-19, similar to most humans. Experimental depletion of T cells slightly prolonged their clearance of virus, but there was no increase in disease severity. Furthermore, they were able to develop protection from a second infection and produced antibodies capable of neutralizing the virus. They also developed immunological memory, which allows a much stronger and more rapid response upon a second infection. These results suggest that T cells are not critical for recovery from acute SARS-CoV-2 infections in this model and point toward B cell responses and antibodies as the essential mediators of protection from re-exposure.