SARS-CoV-2 infection generates tissue-localized immunological memory in humans

Adaptive immune responses to SARS-CoV-2 infection have been extensively characterized in blood; however, most functions of protective immunity must be accomplished in tissues. Here, we report from examination of SARS-CoV-2 seropositive organ donors (ages 10 to 74) that CD4⁺ T, CD8⁺ T, and B cell memory generated in response to infection is present in the bone marrow, spleen, lung, and multiple lymph nodes (LNs) for up to 6 months after infection. Lungs and lung-associated LNs were the most prevalent sites for SARS-CoV-2–specific memory T and B cells with significant correlations between circulating and tissue-resident memory T and B cells in all sites. We further identified SARS-CoV-2–specific germinal centers in the lung-associated LNs up to 6 months after infection. SARS-CoV-2–specific follicular helper T cells were also abundant in lung-associated LNs and lungs. Together, the results indicate local tissue coordination of cellular and humoral immune memory against SARS-CoV-2 for site-specific protection against future infectious challenges.