Alzheimer's disease (AD) is a multifactorial systemic disease that is triggered, at least in part, by the accumulation of β-amyloid (Aβ) peptides in the brain, but it also depends on immune system-mediated regulation. Recent studies suggest that B cells may play a role in AD development and point to the accumulation of clonally expanded B cells in AD patients. However, the specificity of the clonally expanded B cells is unknown, and the contribution of Aβ-specific B cells to AD pathology development is unclear. In this study, we have developed a novel method to identify Aβ-specific B cells by flow cytometry using fluorescent tetramers. The suggested method also enables the identification of B-cell clones specific to a more pathology-provoking form of Aβ with an isomerized Asp7 residue (Iso-D7-Aβ) that accumulates in elderly people and in AD patients. The method has been verified using mice immunized with antigens containing the isomerized or non-isomerized Aβ N-terminus peptides. In addition, we describe a new method for the detection of Iso-D7-Aβ-specific antibodies, which was tested on mouse serum. These methods are of potential importance in research aimed at studying AD and may be also utilized for diagnostic and therapeutic purposes.
© The Author(s) 2025. Published by Oxford University Press.

Previously, we reported the development of a human Aγ-globin gene lentivirus (LV), GbG, which expresses high levels of HbF to correct the sickle cell anemia (SCA) phenotype in the Berkeley SCA mouse model, and then modified the γ-globin gene by substituting glycine at codon 16 with aspartic acid in the Aγ-globin gene to generate GbGM LV. In the present study, we evaluated the long-term safety of human Aγ-globin gene carrying GbGM LV in wild-type mice after primary and secondary transplants of GbGM-modified hematopoietic stem cells (HSC) over 18 months. The safety of the GbGM bone marrow transplant was assessed by monitoring the effects on body weight, hematology, histopathology, malignancy formation, and survival. Mice transplanted with Mock-transduced and spleen focus forming virus (SFFV) γ-retroviral vector (RV)-transduced HSC served as negative and positive controls, respectively. The mean donor-cell engraftment was comparable across Mock, GbGM LV, and SFFV RV groups. There were no significant differences in body weight, clinical signs, immunophenotype, or histopathology in the GbGM-treated mice compared to controls. Four SFFV RV-treated mice, but none of the GbGM-treated mice, developed donor-derived, vector-positive lymphomas as demonstrated by flow cytometry analysis and in situ hybridization. These results highlight the safety of the administration of GbGM LV-modified HSC with long-term follow-up after primary and secondary transplants in mice. This data supported the initiation of phase 1/2 first-in-human SCA clinical trial in the United States.
Copyright: © 2024 Shadid et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza virus co-infections present a heightened COVID-19 disease and hospitalization cases. Here, we studied the immunogenicity and efficacy of an influenza-A/PR8 virus-like particle ( Flu VLP)-based hybrid vaccine candidate displaying GPI-anchored SARS-CoV-2 receptor binding domain fused to GM-CSF and GPI-anchored interleukin-12 ( Flu VLP-RBD) in rhesus macaques. Animals (n=4/group) received two doses of either Flu VLP or Flu VLP-RBD vaccine four weeks apart and were challenged with SARS-CoV-2 (WA1/2020) infection via intranasal and intratracheal routes. We determined vaccine-induced IgG and neutralizing antibody titers in serum and their association with viral replication in the lower and upper airways (lung, throat, and nose) and lung-associated pathologies. Flu VLP-RBD vaccine induced a strong binding IgG in serum against multiple SARS-CoV-2 variants (WA1/2020, Delta and Omicron; BA.1). Both vaccines induced strong influenza A/PR8-specific IgG. Following the SARS-CoV-2 challenge, all four animals in the Flu VLP-RBD group showed a profound control of virus replication in all three airway compartments as early as day 2 through day 10 (day of euthanasia). This level of viral control was not observed in the Flu VLP group as 2-3 animals exhibited high virus replication in all three airway compartments. The protection in the Flu VLP-RBD vaccinated group correlated positively with post challenge neutralizing antibody titer. These results demonstrated that a Flu VLP-based hybrid SARS-CoV-2 vaccine induces strong antibody responses against influenza-A/PR8 and multiple SARS-CoV-2 RBD variants and protects from SARS-CoV-2 replication in multiple compartments in macaques. These findings provide important insights for developing multivalent vaccine strategies for respiratory viruses. Importance Co-infection with multiple respiratory viruses poses a greater risk than individual infections, especially for individuals with underlying health conditions. Studies in humans consistently demonstrated that simultaneous infection with SARS-CoV-2 and influenza leads to more severe respiratory illness and an increased rate of hospitalization. Therefore, developing hybrid vaccines targeting multiple respiratory viruses is of high importance. The hybrid vaccines also help to reduce the economic and logistic burden associated with vaccine coverage, distribution and storage. Here, we evaluate the immunogenicity and effectiveness of a novel hybrid flu-SARS-CoV-2 vaccine candidate using a nonhuman primate pre-clinical model. Our findings reveal that this vaccine elicits a strong immune response against influenza and SARS-CoV-2 viruses. Importantly, it provides strong protection against SARS-CoV-2 infection and associated pathological conditions.

In mammals, males and females show marked differences in immune responses. Males are globally more sensitive to infectious diseases, while females are more susceptible to systemic autoimmunity. X-chromosome inactivation (XCI), the epigenetic mechanism ensuring the silencing of one X in females, may participate in these sex biases. We perturbed the expression of the trigger of XCI, the noncoding RNA Xist, in female mice. This resulted in reactivation of genes on the inactive X, including members of the Toll-like receptor 7 (TLR7) signaling pathway, in monocyte/macrophages and dendritic and B cells. Consequently, female mice spontaneously developed inflammatory signs typical of lupus, including anti-nucleic acid autoantibodies, increased frequencies of age-associated and germinal center B cells, and expansion of monocyte/macrophages and dendritic cells. Mechanistically, TLR7 signaling is dysregulated in macrophages, leading to sustained expression of target genes upon stimulation. These findings provide a direct link between maintenance of XCI and female-biased autoimmune manifestations and highlight altered XCI as a cause of autoimmunity.

Hematopoietic stem cells (HSCs) produce all essential cellular components of the blood. Stromal cell lines supporting HSCs follow a vascular smooth muscle cell (vSMC) differentiation pathway, suggesting that some hematopoiesis-supporting cells originate from vSMC precursors. These pericyte-like precursors were recently identified in the aorta-gonad-mesonephros (AGM) region; however, their role in the hematopoietic development in vivo remains unknown. Here, we identify a subpopulation of NG2+Runx1+ perivascular cells that display a sclerotome-derived vSMC transcriptomic profile. We show that deleting Runx1 in NG2+ cells impairs the hematopoietic development in vivo and causes transcriptional changes in pericytes/vSMCs, endothelial cells and hematopoietic cells in the murine AGM. Importantly, this deletion leads also to a significant reduction of HSC reconstitution potential in the bone marrow in vivo. This defect is developmental, as NG2+Runx1+ cells were not detected in the adult bone marrow, demonstrating the existence of a specialised pericyte population in the HSC-generating niche, unique to the embryo.
© 2024. The Author(s).