Persistence of T Cell and Antibody Responses to SARS-CoV-2 Up to 9 Months after Symptom Onset
Jaclyn C. Law, Mélanie Girard, Gary Chao, Lesley A. Ward, Baweleta Isho, Bhavisha Rathod, Karen Colwill, Zhijie Li, James M. Rini, Feng Yun Yue, Samira Mubareka, Allison McGeer, Mario Ostrowski, Jennifer L. Gommerman, Anne‐Claude Gingras, Tania H. Watts
Abstract
Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces T cell, B cell, and Ab responses that are detected for several months in recovered individuals. Whether this response resembles a typical respiratory viral infection is a matter of debate. In this study, we followed T cell and Ab responses in 24 mainly nonhospitalized human subjects who had recovered from PCR-confirmed SARS-CoV-2 infection at two time points (median of 45 and 145 d after symptom onset). Ab responses were detected in 95% of subjects, with a strong correlation between plasma and salivary anti-spike (anti-S) and anti—receptor binding domain IgG, as well as a correlation between circulating T follicular helper cells and the SARS-CoV-2–specific IgG response. T cell responses to SARS-CoV-2 peptides were determined using intracellular cytokine staining, activation markers, proliferation, and cytokine secretion. All study subjects had a T cell response to at least one SARS-CoV-2 Ag based on at least one T cell assay. CD4+ responses were largely of the Th1 phenotype, but with a lower ratio of IFN-γ– to IL-2–producing cells and a lower frequency of CD8+:CD4+ T cells than in influenza A virus (IAV)-specific memory responses within the same subjects. Analysis of secreted molecules also revealed a lower ratio of IFN-γ to IL-2 and an altered cytotoxic profile for SARS-CoV-2 S- and nucleocapsid-specific responses compared with IAV-specific responses. These data suggest that the memory T cell phenotype after a single infection with SARS-CoV-2 persists over time, with an altered cytokine and cytotoxicity profile compared with long-term memory to whole IAV within the same subjects.