Innate and adaptive immune defects associated with lower SARS-CoV-2 BNT162b2 mRNA vaccine response in elderly people

Abstract

The immune factors associated with impaired SARS-CoV-2 vaccine response in the elderly are mostly unknown. We studied old and young people vaccinated with SARS-CoV-2 BNT162b2 mRNA before and after the first and second dose. Aging was associated with a lower anti-RBD IgG levels and a decreased magnitude and polyfunctionality of SARS-CoV-2 specific T cell response. The dramatic decrease in thymic function in the elderly, which fueled alteration in T cell homeostasis, and lower CD161+ T cell levels were associated with decreased T cell response two months after vaccination. Additionally, a deficient dendritic cell (DC) homing, activation and Toll like receptor (TLR)-mediated function, along with a proinflammatory functional profile in monocytes, were observed in the elderly, which was also related to lower specific T cell response after vaccination. These findings might be relevant for the improvement of the current vaccination strategies and for the development of new vaccine prototypes.

The importance of booster vaccination in the context of Omicron wave

“…In terms of cellular immunity, older adults show lower polyfunctional CD4+ and CD8+ T cells responses than younger adults, as the upregulation of thymosuppressive cytokines can lead to thymic involution with age ( 87 ). Dendritic cell homing and dendritic cell-induced T cell proliferation are also reduced with aging ( 90 , 91 ). By the way, specific T cells can produce different cytokines and exhibit cytotoxic responses to vaccines, but are diminished in the elderly ( 91 ).…”

“…Dendritic cell homing and dendritic cell-induced T cell proliferation are also reduced with aging ( 90 , 91 ). By the way, specific T cells can produce different cytokines and exhibit cytotoxic responses to vaccines, but are diminished in the elderly ( 91 ).…”