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: Immune-modulating medications for inflammatory bowel diseases (IBD) have been associated with suboptimal vaccine responses. There is conflicting data with SARS-CoV-2 vaccination. METHODS: We measured SARS-CoV-2 vaccine immunogenicity at 2 weeks post 2nd mRNA vaccine in IBD patients as compared to normal healthy donors (NHD). We measured humoral immune responses to SARS-CoV-2: anti-spike Immunoglobulin G (IgG) and anti-receptor binding domain (RBD) IgG were measured by ELISA, and neutralizing antibody titers were measured using recombinant, reporter SARS-CoV-2. Antigen specific memory B cells were measured using recombinant SARS-CoV-2 proteins. Activation induced marker T cell (AIM) assays were performed using SARS-CoV-2 spike megapools. Immunophenotyping was performed by flow cytometry. RESULTS: We enrolled 29 patients with IBD (19 with Crohn's disease, 10 with ulcerative colitis) on infliximab (IFX) monotherapy (N=9), IFX combination therapy with a thiopurine (N=9), vedolizumab monotherapy (N= 11) as compared to matched NHD (N=12). At 2 weeks post vaccination, all subjects made detectable anti-spike IgG and anti-RBD IgG. There were no differences in anti-spike IgG titers among the different groups. IBD patients on IFX monotherapy, but not IBD patients on IFX combination therapy or vedolizumab monotherapy, had lower anti-RBD and neutralization titers as compared to NHD (p-value: 0.041 and 0.023, respectively) (Fig. 1). There were no significant differences in the percentage of spike-specific or RBD-specific memory B cells in IBD patients as compared to NHD (Fig. 1). There were no differences in the percentage of spike-specific CD4+ or CD8+ T cells in all IBD patients as compared to NHDs (Fig. 2). CONCLUSIONS: We demonstrate overall comparable and perserved cell-mediated immunity to SARS-CoV-2 vaccination in a small cohort of IBD patients treated with a range of different immune-modulating medications as compared to healthy controls. Larger numbers of patients are needed to validate these findings.