Surviving Older Patients Show Preserved Cellular and Humoral Immunological Memory Several Months After SARS-CoV-2 Infection

García-Torre, Alejandra; Bueno-García, Eva; López-Martínez, Rocío; Rioseras, Beatriz; Moro-García, Marco Antonio; Alonso-Alvarez, Sara; Lluna-González, Alba; Sousa-Fernández, Alejandra; Fernández-Gudin, Marta; Campos-Riopedre, Laura; Castro-del Cueto, Corina; Pérez-Fernández, Ana Belén; Alonso-Rodríguez, Ana; Menéndez-Peña, Carla; Menéndez-Peña, Lara; García-Arnaldo, Noelia; Feito-Díaz, Estefanía; Fernández-Lorences, Adriana; Fraile-Manzano, Agustín; Fernández-Iglesias, Carolina; Rivera, José Arturo; Pérez-Fonseca, Carmen; Urdiales-Ruano, Estibaliz; Debán-Fernández, María; Mendes-Moreira, Hugo; Herrero-Puente, Pablo; Alonso-Arias, Rebeca

Understanding how older people respond to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical if we are to confront the coronavirus disease 2019 (COVID-19) pandemic and establish effective vaccination strategies. Immunosenescence reduces the ability to respond to neoantigens and may compromise the life of infected individuals. Here, we analyzed the immunological memory to SARS-CoV-2 in 102 recovered patients aged over 60 years several months after the infection had been resolved. Specific memory T lymphocytes against the virus were measured by interferon-γ (IFN-γ) and granzyme B release by ELISpot; memory B-lymphocyte responses were quantified by detection of anti-S IgG1 producer cells by ELISpot and anti-S and anti-N antibodies were determined by enzyme-linked immunosorbent assay (ELISA). Memory T lymphocytes were found in peripheral blood of most of the studied donors, more than 7 months after the infection in some of them. Fewer patients maintained memory B lymphocytes, but antibodies, mainly anti-S, were highly durable and positively correlated with T responses. More robust humoral responses were found in patients who had more severe symptoms and had been admitted to hospital. We concluded that specific immunity against SARS-CoV-2 is effectively preserved regardless of age, despite the great heterogeneity of their immune responses, and that memory T lymphocytes and anti-S IgG might be more durable than memory B cells and anti-N IgG.