A comparative characterization of SARS-CoV-2-specific T cells induced by mRNA or inactive virus COVID-19 vaccines

Adaptive immune responses and cytokine immune profiles in humans following prime and boost vaccination with the SARS-CoV-2 CoronaVac vaccine

“…Data coming from sever COVID-19 patients found an damaged function of CD4 + T cells, associated with lower IFN-γ secretion [ 34 ]. In addition, vaccine-induced multi-protein specific T cell responses were largely preserved against the SARS-CoV-2 variant [ 35 – 37 ]. Recent studies proved inactivated SARS-CoV-2 vaccine-induced multi-protein specific T cell response against the Omicron variant and cross-recognition of the different variants by CD4 + and CD8 + T-cells was maintained after booster vaccination [ 36 , 37 ].…”

“…This result was consistent with previously published article [ 38 ]. However, another study found the response to membrane and nucleoprotein remained largely unchanged after the third vaccination dose [ 35 ]. Importantly, vaccine-induced CD4 + T cell responses to RBD protein were more prominent than CD8 + T cell responses, in agreement with recent study [ 35 ].…”

“…However, another study found the response to membrane and nucleoprotein remained largely unchanged after the third vaccination dose [ 35 ]. Importantly, vaccine-induced CD4 + T cell responses to RBD protein were more prominent than CD8 + T cell responses, in agreement with recent study [ 35 ]. Data showed substantial cross-reactive coronavirus T cells was observed in unexposed individuals [ 18 , 39 , 40 ].…”

Role of inactivated SARS-CoV-2 vaccine induced T cell responses in ameliorating COVID-19 severity

“…However, an unaddressed important question was whether inactivated vaccines elicited a comparable magnitude of T-cell response with that of S-mRNA vaccines. Recently, Joey Ming Er Lim et al performed a comparative analysis of SARS-CoV-2-specific T-cell responses induced by mRNA or inactivated COVID-19 vaccines among healthy populations ( Lim et al, 2022 ). The results showed that inactivated vaccines induced a lower magnitude of S-specific T-cell response than mRNA vaccines.…”

“…The results showed that inactivated vaccines induced a lower magnitude of S-specific T-cell response than mRNA vaccines. However, compared to the sole S-specific T-cell response induced by mRNA vaccines, inactivated vaccines induced a wider range of heterogenicity of T-cell responses targeting M, N, and other structural proteins of SARS-CoV-2, which compensated for the lower magnitude of T-cell response against spike protein, and made the total T cell response induced by inactivated vaccine quantitatively comparable to that induced by mRNA vaccine ( Lim et al, 2022 ). In addition, it has been shown that the SARS-CoV-2-specific CD4+ T-cell-response seems to be conserved against the prototype strain, as well as different variants of concerns (VOCs) of SARS-CoV-2, due to mutations occurring mainly within the non-CD4+ T-cell epitope regions ( Mazzoni et al, 2022 ).…”