ABSTRACT
Vaccine-elicited SARS-CoV-2 antibody responses are an established correlate of protection against viral infection in humans and non-human primates. However, it is less clear that vaccine-induced immunity is able to limit infection-elicited inflammation in the lower respiratory tract. To assess this, we collected bronchoalveolar lavage fluid samples post-SARS-CoV-2 strain USA-WA1/2020 challenge from rhesus macaques vaccinated with mRNA-1273 in a dose-reduction study. Single-cell transcriptomic profiling revealed a broad cellular landscape 48 hours post-challenge with distinct inflammatory signatures that correlated with viral RNA burden in the lower respiratory tract. These inflammatory signatures included phagocyte-restricted expression of chemokines such as CXCL10 (IP10) and CCL3 (MIP-1A) and the broad expression of interferon-induced genes such as MX1, ISG15, and IFIT1. Induction of these inflammatory profiles was suppressed by prior mRNA-1273 vaccination in a dose-dependent manner, and negatively correlated with pre-challenge serum and lung antibody titers against SARS-CoV-2 spike. These observations were replicated and validated in a second independent macaque challenge study using the B.1.351/beta-variant of SARS-CoV-2. These data support a model wherein vaccine-elicited antibody responses restrict viral replication following SARS-CoV-2 exposure, including limiting viral dissemination to the lower respiratory tract and infection-mediated inflammation and pathogenesis. One Sentence SummarySingle cell RNA sequencing analysis demonstrates that mRNA-1273 vaccination limits the development of lower respiratory tract inflammation in SARS-CoV-2 challenged rhesus macaques
ABSTRACT
SARS-CoV-2 represents an unprecedented public health challenge with many unknowns remaining regarding the factors that impact viral pathogenicity and the development of immunity after infection. While the majority of SARS-CoV-2 infected individuals with mild-to-moderate COVID-19 resolve their infection with few complications, a significant number of individuals experienced prolonged symptoms lasting for weeks after initial diagnosis. Persistent viral infections are commonly accompanied by immunologic dysregulation, especially within the cellular immune compartment. However, it is unclear if persistent mild-to-moderate COVID-19 impacts the development of virus-specific cellular immunity. To this end, we analyzed the development of SARS-CoV-2 specific cellular immunity in convalescent COVID-19 patients who experienced eight days or fewer of COVID-19 symptoms, or symptoms persisting for 18 days or more. We observed that the duration of COVID-19 symptoms minimally impacts the magnitude, antigen specificity, and transcriptional profile of SARS-CoV-2 specific cellular immunity within both the CD4+ and CD8+ T cell compartments. Furthermore, we observed that reactivity against the structural N protein from SARS-CoV-2 in convalescent COVID-19 patients correlates with the amount of reactivity against the seasonal human coronaviruses 229E and NL63. These results provide additional insight into the complex processes that regulate the development of cellular immunity against SARS-CoV-2 and related human coronaviruses.
