Paving the Way Towards Precision Vaccinology: The Paradigm of Myocarditis After Coronavirus Disease 2019 (COVID-19) Vaccination.

Systems vaccinology approaches have introduced novel tools for the evaluation of the safety profile of novel vaccine antigens by developing biomarkers of vaccine reactogenicity associated with potential adverse events. The use of such approaches may prove extremely advantageous in the context of a global pandemic where accelerated approval of new vaccine formulations for all ages is essential for the containment of the epidemic. The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had devastating effects on global health, but the emergency authorization of mRNA vaccines significantly reduced SARS-CoV-2-associated morbidity and mortality. Despite their favorable safety profile in adult populations, recent reports have raised concerns about an association of the mRNA-based vaccines with acute myocarditis, predominantly among male adolescents and young adults following the second vaccine dose. Here, we review data on myocarditis epidemiology following SARS-CoV-2 mRNA vaccination and describe potential mechanisms involved that may explain the sex- and age-related differences, focusing on mRNA immune reactivity. The case of vaccine-associated myocarditis highlights the need to incorporate precision vaccinology approaches for the development of safe and effective vaccines for everyone.

Evaluation of Protective Efficacy of Selected Immunodominant B-Cell Epitopes within Virulent Surface Proteins of Streptococcus pneumoniae.

Four previously identified immunodominant B-cell epitopes, located within known virulent pneumococcal proteins CbpD, PhtD, PhtE, and ZmpB, had shown promising in vivo immunological characteristics, indicating their potential to be used as vaccine antigens. In this study, we further evaluated the opsonophagocytic activity of antibodies against these epitopes and their capacity to protect mice from pneumococcal sepsis. An opsonophagocytic killing assay (OPKA) revealed that OPKA titers of human anti-peptide antibodies against pneumococcal serotypes 1, 3, and 19A were significantly higher (P < 0.001) than those of the control sera, suggesting their functional potential against virulent clinical isolates. Data obtained from mice actively immunized with any of the selected epitope analogues or with a mixture of these (G_Mix group) showed, compared to controls, enhanced survival against the highly virulent pneumococcal serotype 3 (P < 0.001). Moreover, passive transfer of hyperimmune serum from G_Mix to naive mice also conferred protection to a lethal challenge with serotype 3, which demonstrates that the observed protection was antibody mediated. All immunized murine groups elicited gradually higher antibody titers and avidity, suggesting a maturation of immune response over time. Among the tested peptides, PhD_pep19 and PhtE_pep40 peptides, which reside within the zinc-binding domains of PhtD and PhtE proteins, exhibited superior immunological characteristics. Recently it has been shown that zinc uptake is of high importance for the virulence of Streptococcus pneumoniae; thus, our findings suggest that these epitopes deserve further evaluation as novel immunoreactive components for the development of a polysaccharide-independent pneumococcal vaccine.

Non-traditional adipokines in pediatric HIV-related lipodystrophy: a-FABP as a biomarker of central fat accumulation.

BACKGROUND: Lipodystrophy characterized by adipose tissue redistribution and lipid and glucose metabolism abnormalities, is common among HIV-infected adults and children on highly-active-antiretroviral-therapy (HAART). In a previous study of HIV-infected children, we did not detect insulin resistance, despite a high percentage of body fat redistribution abnormalities. AIM OF THE STUDY: To investigate the non-traditional adipokines Retinol-binding-Protein-4 (RBP4), neutrophil-gelatinase-associated-lipocalin (NGAL), a-Fatty-Acid-Binding-Protein (a-FABP) and YKL-40 in HIV-infected children on highly-active-antiretroviral-therapy and evaluate their possible association to lipodystrophic changes or insulin resistance. METHODS: Seventeen vertically HIV-infected children (mean age: 12.5 years, mean duration of HAART: 5.2 years) and 20 age- and BMI-matched controls were recruited. The HIV-children were re-evaluated after 12 months. RBP4, NGAL, a-FABP and YKL-40 were assessed at study entry and 12 months later and were correlated to body fat content and insulin resistance. RESULTS: RBP4 values were similar at study entry and 12 months later in HIV-children and controls and showed no correlation to body fat or insulin resistance. NGAL was lower in HIV children at study entry but normalized after 12 months with no positive correlation to insulin resistance. a-FABP was positively correlated to body fat content, especially to trunk fat, both at initial evaluation and at follow-up in HIV children and, after prolonged highly-active-antiretroviral-therapy, it was also positively correlated to insulin resistance. CONCLUSIONS: This study is the first one to demonstrate that a-FABP could be a useful marker in unraveling central fat accumulation in HIV-infected children on highly-active-antiretroviral-therapy. Large prospective studies are needed to confirm these results.