In this pandemic period, vaccination against SARSCoV- 2 is an essential weapon. However, the immune memory induced by current vaccines remains ephemeral, requiring early booster shots. It is primordial to improve this vaccine memory.~Recently it has been demonstrated that monocytes from certain individuals hospitalized for SARSCoV-2 infection spontaneously overproduced oxygenated derivatives (ROS) capable of inducing DNA damage in neighboring cells and T cell apoptosis (Kundura et al., 2022). In agreement with these observations, up to 50% of peripheral blood mononuclear cells (PBMC) from these patients showed DNA damage and its intensity was correlated with the percentage of apoptotic CD8+ T cells and lymphopenia.~Upon entry into the target cell, SARS-CoV-2 induces the internalization of its receptor, the protease Angiotensin Converting Enzyme 2 (ACE2), which is able to degrade Angiotensin II (AngII). Consequently, the circulating level of AngII was observed to be increased in some COVID-19 patients. It was also found that AngII induced monocyte ROS production via its receptor Angiotensin receptor 1 (AT1), making monocytes capable of damaging the DNA of co-cultured cells. Moreover, the plasma level of AngII in patients correlates with the level of ROS production and the ability to damage DNA of their monocytes. The level of anti SARS-CoV-2 antibodies was shown to be inversely correlated with the level of monocyte production of ROS production during the acute phase. This suggests that the activation cascade leading to lymphopenia described could damage the specific immune memory.~Now, a recent article has established the presence of circulating S1 vaccine antigen following the injection of an anti-SARS-CoV-2 vaccine with mRNA vaccine from D1 to D7 at a level of 68 ± 21 pg/mL (Ogata et al. 2022) similar to the level described in COVID-19 (Ogata et al. 2020). If the cascade of events we have identified is triggered by the circulation of the vaccine antigen, this could lead to could result in a reduced vaccine memory via lymphocyte apoptosis.~Knowing that the vaccine antigen includes the ACE2 binding moiety (RBD), the hypothesis is that circulating vaccine antigen could reduce the enzymatic activity of ACE2, and thus increase circulating AngII concentration, monocyte ROS production and lymphocyte apoptosis. This hypothesis is supported by the fact that the Spike protein of SARSCoV-1, which uses the same receptor as SARS-CoV-2, induces a decrease in expression and activation of the Angiotensin II pathway in mice (Kuba et al. 2005).
Knowing that the vaccine antigen includes the ACE2 binding moiety (RBD), the hypothesis is that circulating vaccine antigen could reduce the enzymatic activity of ACE2, and thus increase circulating AngII concentration, monocyte ROS production and lymphocyte apoptosis. This hypothesis is supported by the fact that the Spike protein of SARSCoV-1, which uses the same receptor as SARS-CoV-2, induces a decrease in expression and activation of the Angiotensin II pathway in mice (Kuba et al. 2005).