Modifications of self antigens that occur during apoptosis might be involved in the generation of neo-antigens, which can break tolerance and induce autoimmunity. We have previously identified an epitope at residues 131-151 of the U1-70K snRNP protein, recognized by IgG antibodies and CD4 + T cells from at least two strains of lupus mice. With the aim of investigating the possible role of phosphorylation on the antigenicity of peptide 131-151 and to gain a better understanding of how this peptide can drive autoimmune response, we synthesized two peptides phosphorylated on Ser 137 and 140 , respectively. We show here that peptide P140 phosphorylated on Ser 140 is recognized by both CD4 + T cells and antibodies from MRL/lpr mice. Furthermore, intravenous administration to lupus-prone MRL/lpr mice of P140 in saline (but not of the non-phosphorylated peptide) decreased proteinuria and anti-DNA antibody production, and significantly prolonged survival of treated mice. We further demonstrated that P140 is recognized by antibodies from lupus patients and binds to various HLA DR molecules, offering new hope for manipulating T cell response in humans.

The most widespread Plasmodium species, Plasmodium vivax, poses a significant public health threat. An effective vaccine is needed to reduce global malaria burden. Of the erythrocytic stage vaccine candidates, the 19 kDa fragment of the P. vivax Merozoite Surface Protein 1 (PvMSP119) is one of the most promising. Our group has previously defined several promiscuous T helper epitopes within the PvMSP1 protein, with features that allow them to bind multiple MHC class II alleles. We describe here a P. vivax recombinant modular chimera based on MSP1 (PvRMC-MSP1) that includes defined T cell epitopes genetically fused to PvMSP119. This vaccine candidate preserved structural elements of the native PvMSP119 and elicited cytophilic antibody responses, and CD4+ and CD8+ T cells capable of recognizing PvMSP119. Although CD8+ T cells that recognize blood stage antigens have been reported to control blood infection, CD8+ T cell responses induced by P. falciparum or P. vivax vaccine candidates based on MSP119 have not been reported. To our knowledge, this is the first time a protein based subunit vaccine has been able to induce CD8+ T cell against PvMSP119. The PvRMC-MSP1 protein was also recognized by naturally acquired antibodies from individuals living in malaria endemic areas with an antibody profile associated with protection from infection. These features make PvRMC-MSP1 a promising vaccine candidate.

Despite the increasing evidence of the benefit of corticosteroids for the treatment of moderate-severe coronavirus disease 2019 (COVID-19) patients, no data are available about the potential role of high doses of steroids for these patients. We evaluated the mortality, the risk of need for mechanical ventilation (MV), or death and the risk of developing a severe acute respiratory distress syndrome (ARDS) between high (HD) and standard doses (SD) among patients with a severe COVID-19. All consecutive confirmed COVID-19 patients admitted to a single center were selected, including those treated with steroids and an ARDS. Patients were allocated to the HD (≥ 250 mg/day of methylprednisolone) of corticosteroids or the SD (≤ 1.5 mg/kg/day of methylprednisolone) at discretion of treating physician. Five hundred seventy-three patients were included: 428 (74.7%) men, with a median (IQR) age of 64 (54-73) years. In the HD group, a worse baseline respiratory situation was observed and male gender, older age, and comorbidities were significantly more common. After adjusting by baseline characteristics, HDs were associated with a higher mortality than SD (adjusted OR 2.46, 95% CI 1.59-3.81, p < 0.001) and with an increased risk of needing MV or death (adjusted OR 2.35, p = 0.001). Conversely, the risk of developing a severe ARDS was similar between groups. Interaction analysis showed that HD increased mortality exclusively in elderly patients. Our real-world experience advises against exceeding 1-1.5 mg/kg/day of corticosteroids for severe COVID-19 with an ARDS, especially in older subjects. This reinforces the rationale of modulating rather than suppressing immune responses in these patients.

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Merozoite Surface Protein-1 (MSP-1) has been considered as a malaria vaccine candidate. It is processed during the Plasmodium falciparum invasion process of red blood cells (RBCs). A conserved MSP-1 C-terminal peptide was identified as a high-activity erythrocyte-binding peptide (HAEBP) termed 1585. Since conserved HAEBPs are neither antigenic nor immunogenic we decided to assess the significance of a single peptide bond replacement in 1585. Thus, two pseudopeptides were obtained by introducing a Y[CH2-NH] reduced amide isoster into the 1585 critical binding motif. The pseudopeptides bound to different HLA-DR alleles, suggesting that backbone modifications affect MHC-II binding patterns. Pseudopeptide-antibodies inhibit in vitro parasite RBC invasion by recognizing MSP-1. Each pseudopeptide-induced antibody shows distinct recognition patterns. 1H-NMR studies demonstrated that isoster bonds modulate the pseudopeptides' structure and thus their immunological properties, therefore representing a possible subunit malaria vaccine component.