Humoral and cellular response of two different vaccines against SARS-CoV-2 in a group of healthcare workers: An observational study.

On March 13, 2021, Tunisia started a widespread immunization program against SARS-CoV-2 utilizing different vaccinations that had been given emergency approval. Herein, we followed prospectively a cohort of participant who received COVID-19 vaccine (Pfizer BioNTech and Sputnik-Gameleya V). The goal of this follow-up was to define the humoral and cellular immunological profile after immunization by assessing neutralizing antibodies and IFN- γ release. 26 vaccinated health care workers by Pfizer BioNTech (n=12) and Sputnik-Gameleya V (n=14) were enrolled from June to December 2021 in Military hospital of Tunis. All consenting participants were sampled for peripheral blood after three weeks of vaccination. The humoral response was investigated by the titer of anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies to S1 protein. The CD4 and CD8 T cell responses were evaluated by the QuantiFERON® SARS-CoV-2 (Qiagen® Basel, Switzerland). Regardless the type of vaccine, the assessment of humoral and cellular response following vaccination showed a strong involvement of the later with expression of IFN-γ as compared to antibodies secretion. Moreover, we showed that people with past SARS-CoV-2 infection developed high levels of antibodies than those who are not previously infected. However, no significant difference was detected concerning interferon gamma (IFN-γ) expression by CD4 and CD8 T cells in health care worker (HCW) previously infection or not with COVID-19 infection. Analysis of immune response according to the type of vaccine, we found that Pfizer BioNTech induced high level of humoral response (91.66%) followed by Sputnik-Gameleya V (64.28%). However, adenovirus vaccine gave a better cellular response (57.14%) than mRNA vaccine (41.66%). Regarding the immune response following vaccine doses, we revealed a significant increase of neutralizing antibodies and IFN-γ release by T cells in patients fully vaccinated as compared to those who have received just one vaccine. Collectively, our data revealed a similar immune response between Pfizer BioNTech and Sputnik-Gameleya V vaccine with a slight increase of humoral response by mRNA vaccine and cellular response by adenovirus vaccine. It's evident that past SARS-CoV-2 infection was a factor that contributed to the vaccination's increased immunogenicity. However, the administration of full doses of vaccines (Pfizer BioNTech or Sputnik-Gameleya V) induces better humoral and cellular responses detectable even more than three months following vaccination.

Immune Cell Response during COVID-19 Infection and following SARS-CoV-2 Vaccination in Patients Admitted to Intensive Care Unit.

Background: Immune response plays a crucial role in virus clearance during COVID-19 infection and underpins vaccine efficacy. Herein, we aimed to assess the immune response during COVID-19 infection and following SARS-CoV-2 vaccination. Methods: In this retrospective study, 94 confirmed COVID-19 patients admitted to the intensive care unit were categorized into unvaccinated patients (n = 50), including 33 deceased and 17 discharged patients, and vaccinated group (n = 44) with 26 deceased and 18 discharged patients. Records of patients with severe COVID-19 admitted to the ICU between March, 2021 and March, 2022 were gathered and analyzed. Result: The assessment of immune cell counts revealed a large rise of neutrophils associated to decrease number of lymphocytes in patients with COVID-19 infection. In dead patients, we detected a significant correlation between neutrophils and inflammatory parameters such as IL-6 and CRP. Moreover, analysis of immune cell count following vaccination did not reveal any significant difference. However, the most substantial result, herein, detected is the decrease level of IL-6 in vaccinated patients as compared to unvaccinated. The reduce level of IL-6 following vaccination is observed in discharged patients as compared to deceased. Regarding the level of mortality after vaccination, we showed that all patients who received the first dose were died (46.1%, n = 12) as compared to those who have received two doses (34.6%, n = 9) and the third dose of vaccine (19.23%, n = 3) (p=0.0018). Strikingly, studying the inflammatory parameters after each vaccine dose, we revealed a significant decrease of IL-6 level after the booster dose (third dose), especially in vaccinated discharged patients. Conclusions: Neutrophils combined with IL-6 and CRP can be very useful markers to predict disease severity in patients admitted to ICU. The decrease level of IL-6 in vaccinated group pointed out the impact of vaccination to prevent inflammatory cytokine release.

Discriminative expression of CD39 and CD73 in Cerebrospinal fluid of patients with Multiple Sclerosis and Neuro-Behçet's disease.

Treg-mediated immune suppression involves many molecular mechanisms including the cleavage of inflammatory extracellular ATP to adenosine by CD39 ectoenzyme. In the peripheral blood of Multiple Sclerosis (MS) patients, it has been suggested that CD39+ Treg cells have the potential to suppress pro-inflammatory IL-17 secreting cells. Herein, we studied cellular phenotype and mRNA expression of CD39 and CD73 ectoenzymes in the Cerebrospinal fluid (CSF) of MS patients and another neuro-inflammatory disease: the Neuro-behçet's disease (NBD). Using qRT-PCR, we assessed mRNA expression of CD39 and CD73 as well as anti-inflammatory (IL-10) and pro-inflammatory (IL-6, TNF-α, IL-1ß) cytokines in patients Peripheral blood mononuclear cells (PBMCs) and CSF of 28 relapsing-remitting multiple sclerosis (RRMS), 20 NBD and 22 controls with non inflammatory neurological disorders (NIND). The most substantial result in the CSF was the higher expression of CD39 in both RRMS and NBD patients compared to NIND. While, the expression of CD73 in CSF samples of NBD was low. In RRMS samples, we detected a significant positive correlation of both CD39 and CD73 with IL-10 expression. Moreover, results by flow cytometry revealed a high percentage of CD39 Treg cells in RRMS CSF. CD39 was preferentially expressed on B cells of NBD. Regarding inflammatory response, we showed a significant increase of IL-6 mRNA expression in NBD patients CSF while in RRMS this increase concerned TNF-α. These results bring evidence that CD39 correlates positively with an anti-inflammatory IL-10 response in RRMS. In contrast, no such association was observed in CSF of NBD patients and CD39 was preferentially expressed on B cells.