The Immune Response to SARS-CoV-2 Vaccine in a Cohort of Family Pediatricians from Southern Italy

Abstract

In Italy, from January 2021, the Ministry of Health indicated a vaccination plan against COVID for frail patients and physicians based on a three-dose scheme. However, conflicting results have been reported on which biomarkers permit immunization assessment. We used several laboratory approaches (i.e., antibodies serum levels, flow cytometry analysis, and cytokines release by stimulated cells) to investigate the immune response in a cohort of 53 family pediatricians (FPs) at different times after the vaccine. We observed that the BNT162b2-mRNA vaccine induced a significant increase of specific antibodies after the third (booster) dose; however, the antibody titer was not predictive of the risk of developing the infection in the six months following the booster dose. The antigen stimulation of PBMC cells from subjects vaccinated with the third booster jab induced the increase of the activated T cells (i.e., CD4+ CD154+); the frequency of CD4+ CD154+ TNF-α+ cells, as well as the TNF-α secretion, was not modified, while we observed a trend of increase of IFN-γ secretion. Interestingly, the level of CD8+ IFN-γ+ (independently from antibody titer) was significantly increased after the third dose and predicts the risk of developing the infection in the six months following the booster jab. Such results may impact also other virus vaccinations.

Immunocytometric analysis of patients with thymic epithelial tumors revealed that COVID-19 vaccine booster strongly enhanced the immune response

“…None of the 14 patients required hospitalization or oxygen supplementation. This confirms that in patients with TET, the vaccine does not prevent the infection, likely due to the different VOI of the virus that spread in Italy ( 20 ). However, it avoided the severe form of the disease, as was observed in healthy subjects ( 20 , 31 ).…”

“…This confirms that in patients with TET, the vaccine does not prevent the infection, likely due to the different VOI of the virus that spread in Italy ( 20 ). However, it avoided the severe form of the disease, as was observed in healthy subjects ( 20 , 31 ). Moreover, as observed in healthy subjects ( 20 ), humoral and cellular responses to the vaccine are not predictive of a reduced risk of infection.…”

“…In addition, cell-mediated immune responses were assessed at T4 and T5. Various viral VOI were circulating during this period in Southern Italy ( 20 ). Clinical and anamnestic evaluations were performed every four weeks during and after the administration of the full vaccination cycle for up to 12 months from 1 st dose, in order to identify humoral and/or clinical signs or symptoms suggestive of new-onset or worsening autoimmune disorders.…”

“…Peripheral blood mononuclear cells (PBMCs) were collected by density gradient on lymphocyte separation media (Biowest) using Lymphosep tubes (Grenier Bio-One) according to the manufacturer’s instructions. Peripheral PBMCs were cryopreserved as previously described ( 20 ). Blood samples were collected in EDTA tubes for lymphocyte subpopulation analysis.…”

“…To obtain the specific T cell response by the cytokine release assay, PBMCs were plated in a 96-U well plate at 1x10 6 cells per well (100 μL) in complete RPMI medium with 5% human AB serum (Sigma) in the presence of 1 μg/mL monoclonal antibodies against CD28 and CD49d (Becton Dickinson) and stimulated as previously described with slight modifications ( 20 ). The SARS-CoV-2 protein S (Miltenyi Biotec) peptide pools were used at 1 ug.…”