ABSTRACT
Background. We studied immunological response against SARS-CoV-2 after two doses of vaccine in health care workers (HCW) at our Infectious Disease Unit Methods. We enrolled prospectively HCW without (group A) and with previous infection (group B). We collected peripheral blood at baseline (before the BNT162b2 vaccine), T1 (before the 2nd dose), T2 and T6 (after 1 and 6 months after of 2nd dose). The activation induced cell marker assay (AIM) was performed with CD4 and CD8 Spike peptide megapools (MPs). We evaluated the Stimulation Index (SI) as AIM+ stimulated cells/negative control (positive response SI >= 2). Quantitative antibodies (Abs) to Spike-1 protein (S) and to nucleocapside protein (N) were detected with an electrochemiluminescence immunoassay. We tested at T6 the responses to alpha, beta, gamma, delta and epsilon variants MPs.We used the linear mixed model with random intercept adjusted for age and sex to compare specific times to T0. To assess differences over time between groups the interaction with time was tested. Results. In group A 13/22 (59%) were female vs 5/7 (71%) group B, the mean age 40 vs 38 years, respectively. For CD4+ Spike the overall rate of change over time was significant at T1 (p=0.038) and at T2 (p< 0.001) vs T0 with a decreasing at T6 (p not significant) [Figure 1] with a trend of higher response in group A. In group B the CD8 + Spike reactivity increased at T1(p=0.037) and at T6 (p=0.005) vs T0. The interaction between SI and time was statistically significant at T1 (p=0.033);T2 (p= 0.046) and T6 (p=0.035) (mean values in group B higher than A). For overall population, the anti-S Abs significantly increased at T1 vs T0, T2 vs T0 and at T6 vs T0 [Figure 2A]. The group B at T6 retained a higher anti S response but the rate of change significantly differs between the two group (overall interaction: p< 0.001) [Figure 2B]. At T6 in both groups we found a high CD4+ T cells response to epsilon variant, even if not detected as circulant virus. Conclusion. The humoral response was persistent and increased in previous infected subjects. The CD4+T cells response after vaccination retained a response in uninfected subject, with an increasing trend and with a response to non-circulating variants. The vaccine could help the CD8+ T cells reactivity specific for Spike peptides.
ABSTRACT
Introduction: Anti-SARS-CoV2 vaccination induces specific Tand B-cell responses in healthy subjects (HS). In MS patients treated with anti-CD20 drugs, the antibody response is reduced or absent, whereas specific T-cell responses are maintained. It is not known whether and how vaccination affects innate responses mediated by natural killer (NK) cells in HS and in MS patients treated with anti-CD20 drugs. Objective(s): To evaluate whether and how NK cells contribute to the immune response following anti-SARS-CoV2 vaccination in HS and in ocrelizumab-treated MS patients Aims: The aims of this work were: 1) to evaluate the effects of anti-SARS CoV2 vaccination on the phenotype of NK cells from HS and from ocrelizumab-treated MS patients and 2) to evaluate how peptides from the SARS-CoV2 spike protein affect NK cell responses before and after anti-SARS-CoV2 vaccination. Method(s): We enrolled 21 MS patients treated with ocrelizumab and 20 HS. Peripheral blood mononuclear cells (PBMCs) were isolated from peripheral blood and stored under liquid nitrogen. Thawed PBMCs were cultured overnight in presence/absence of SARS-CoV2 peptides or peptides from the cytomegalovirus (CMV), with/without activating cytokines. Phenotype of NK cells through a 13-marker flow cytometry panel and intracellular production of IFN-gamma were evaluated after culture. Result(s): Findings: 1) Vaccination increased the proportion of CD56dim NK cells in HS and MS patients. CD56posCD16neg NK cells, more abundant in MS patients before vaccination, decreased thereafter. Lower pre-vaccination activation capability of NK cells from MS patients compared to HS in response to stimulus with cytokines was reverted by vaccination. 2) Before vaccination, peptides from the SARS-CoV2 protein downregulated the production of IFN- gamma from NK cells of HS, but not ocrelizumabtreated MS patients, who had significantly lower baseline IFN-gamma NK cells 3) After vaccination, peptides from the SARS-CoV2 protein did not affect the production of IFN- gamma from NK cells of HS. Conclusion(s): The results of this work demonstrate anti-SARSCoV2 vaccination increases the proportion of effector CD56dim NK cells in HS and ocrelizumab-treated patients. Spike peptides inhibit the function of NK cells from HS before, but not after vaccination. Such phenomenon may contribute to the pathogenicity of SARS-CoV2 in unvaccinated subjects.
ABSTRACT
Background: SARS-CoV-2 specific T-cell response has been associated with disease severity, immune memory and heterologous response to endemic coronaviruses (HCoV). However, an integrative approach combining a comprehensive analysis of the quality of SARS-CoV-2 specific T-cell response and antibody levels is needed. Methods: We assayed SARS-CoV-2 specific T-cell response in 103 participants. Thirty-seven (18 mild and 19 severe) were hospitalized during acute COVID-19 and 33 were recruited seven months after SARS-CoV-2 infection (19 previously hospitalized (H) and 14 non-hospitalized (NH) during acute infection). Pre-COVID-19 healthy donors (HD, n=33) were included. PBMCs were stimulated with Spike (S) and Nucleocapside (N) SARS-CoV-2 peptide pools. Likewise, an optimized peptide pool of HCoV S protein was used in HD. T-cell polyfunctionality by intracellular cytokine staining (IFN-γ, IL-2, TNF-α, CD107a and perforin (PRF)) was assayed by multiparametric flow cytometry together with measurements of T cell subsets, activation, exhaustion and senescence. Anti-S SARS-CoV-2 and HCoV IgG titers and pro-inflammatory markers were measured in plasma. Non-parametric statistic was used for the analysis. Results: Mild disease was associated with high T-cell polyfunctionality biased to IL-2 production and inversely correlated with anti-S IgG levels (eg, N-specific EM CD4+ IL-2+ T-cell, r=-0.594, p=0.004). However, only IFN-γ combinations without PRF production was mostly observed for severe disease (eg, S-specific TEMRA CD4+ CD107a-IFN-γ+IL-2-PRF-TNF-α-T-cells, p=0.008). Moreover, this response was long-lasting seven months after SARS-CoV-2 infection. Both NH and H individuals presented robust anti-S IgG levels and SARS-CoV-2 specific T-cell response. In addition, only H individuals showed a T-cell exhaustion profile (eg, TEMRA CD4+ TIGIT+ T cells, p=0.0004). Combinations including IL-2, but not IFN-γ, in response to HCoV S protein, were associated with SARS-CoV-2 S-specific T-cell response in HD (eg, S-specific CM CD8+ CD107a-IFN-γ-IL-2+PRF-TNF-α-T-cells, r=5414, p=0.001). Conclusion: T-cell polyfunctionality features were associated with disease severity. Moreover, T-cell response was robust seven months after infection, although previously hospitalized patients showed signs of exhaustion. SARS-CoV-2 and HCoV immune cross-reactivity have implications for protective immunity against SARS-CoV-2 to design new prototypes of vaccines in order to achieve of broader long-lasting protection against COVID-19.
ABSTRACT
Severe coronavirus disease 2019 (COVID-19) pneumonia survivors often exhibit long-term pulmonary sequelae, but the underlying mechanisms or associated local and systemic immune correlates are not known. Here, we have performed high-dimensional characterization of the pathophysiological and immune traits of aged COVID-19 convalescents, and correlated the local and systemic immune profiles with pulmonary function and lung imaging. We found that chronic lung impairment was accompanied by persistent respiratory immune alterations. We showed that functional severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)specific memory T and B cells were enriched at the site of infection compared with those of blood. Detailed evaluation of the lung immune compartment revealed that dysregulated respiratory CD8+ T cell responses were associated with the impaired lung function after acute COVID-19. Single-cell transcriptomic analysis identified the potential pathogenic subsets of respiratory CD8+ T cells contributing to persistent tissue conditions after COVID-19. Our results have revealed pathophysiological and immune traits that may support the development of lung sequelae after SARS-CoV-2 pneumonia in older individuals, with implications for the treatment of chronic COVID-19 symptoms.