Mutations that negatively impact mitochondrial function are highly prevalent in humans and lead to disorders with a wide spectrum of disease phenotypes, including deficiencies in immune cell development and/or function. Previous analyses of mice with a hepatocyte-specific cytochrome c oxidase (COX) deficiency revealed an unexpected peripheral blood leukopenia associated with splenic and thymic atrophy. Here, we use mice with a hepatocyte-specific deletion of the COX assembly factor Sco1 to show that metabolic defects extrinsic to the hematopoietic compartment lead to a pan-lymphopenia represented by severe losses in both B and T cells. We further demonstrate that immune defects in these mice are associated with the loss of bone marrow lymphoid progenitors common to both lineages and early signs of autoantibody-mediated autoimmunity. Our findings collectively identify hepatocyte dysfunction as a potential instigator of immunodeficiency in patients with congenital mitochondrial defects who suffer from chronic or recurrent infections.
© 2025 The Author(s).

Background:Echinococcus granulosus represents a significant threat to animal husbandry and human health, but its consequences are often underestimated. Vaccination can prevent E. granulosus infection. We investigated the immune protective effect induced by the recombinant protein P29 of E. granulosus (rEg.P29) peptide vaccine. Methods: The CD4+ T-, CD8+ T-, Treg-, and CD8+CD107a+ T-cell proportions in the spleen and peripheral blood of infected mice were analyzed using flow cytometry. Additionally, we measured the proportions of IFN-γ and IL-2 secreted by memory T cells, CD19+CD138-B cells, CD19+CD138+ plasmablasts, CD19-CD138+ plasma cells, and CD19+IgD-IgG+ and CD19+IgD-IgA+ memory B cells. Results: No significant differences were noted in CD4+ T-, CD8+ T-, and CD8+CD107a+ Treg-cell percentages among the experimental groups. However, IFN-γ, IL-2, and TNF-α levels and vaccine-specific antibody concentrations in the plasma were significantly elevated in the rEg.P29T+B + CpG + infection and rEg.P29 + CpG + infection groups compared to those in the PBS + infection and CpG + infection groups. Similarly, CD19-CD138+ plasma cell and CD19+IgD-IgG+ and CD19+IgD-IgA+ memory B-cell populations, along with specific antibodies, were significantly higher in these groups. Especially, the average cyst burden in the rEg.P29T+B + CpG + infection and rEg.P29 + CpG + infection groups was significantly reduced compared to that in the PBS + infection and CpG + infection groups. Conclusions: Synthetic peptide vaccines targeting rEg.P29 can effectively inhibit cysts, offering a novel strategy for the development of vaccines against E. granulosus. These findings provide a foundation for further research on the immunogenicity and protective efficacy of rEg.P29-based vaccines.

Antibody-secreting cells (ASCs) are critical regulators of the humoral immune response. However, differences between tissue resident populations versus those that have recently migrated to their final anatomic destination are poorly understood. Here, we present a protocol for using retro-orbital (r.o.) CD45 antibody labeling to identify tissue resident versus recently immigrated ASCs in mice. We describe steps for r.o. injection of antibodies, animal euthanasia, and tissue harvesting. We then detail tissue processing, cell counting, and cell staining for flow cytometry analysis. For complete details on the use and execution of this protocol, please refer to Pioli et al. (2023).1.
Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.

Antibody-secreting cells (ASCs) are key contributors to humoral immunity through immunoglobulin production and the potential to be long-lived. ASC persistence has been recognized in the autoimmune thymus (THY); however, only recently has this population been appreciated in healthy THY tissue. We showed that the young female THY was skewed toward higher production of ASCs relative to males. However, these differences disappeared with age. In both sexes, THY ASCs included Ki-67+ plasmablasts which required CD154(CD40L) signals for their propagation. Single cell RNA-sequencing revealed that THY ASCs were enriched for an interferon responsive transcriptional signature relative to those from bone marrow and spleen. Flow cytometry confirmed that THY ASCs had increased levels of Toll-like receptor 7 as well as CD69 and major histocompatibility complex class II. Overall, we identified fundamental aspects of THY ASC biology which may be leveraged for future in depth studies of this population in both health and disease.
© 2023 The Author(s).

B lymphocytes are exquisitely sensitive to fluctuations in nutrient signaling by the Rag GTPases, and 15% of follicular lymphomas (FLs) harbor activating mutations in RRAGC. Hence, a potential therapeutic approach against malignant B cells is to inhibit Rag GTPase signaling, but because such inhibitors are still to be developed, efficacy and safety remain unknown. We generated knockin mice expressing a hypomorphic variant of RagC (Q119L); RagCQ119L/+ mice are viable and show attenuated nutrient signaling. B lymphocyte activation is cell-intrinsically impaired in RagCQ119L/+ mice, which also show significant suppression of genetically induced lymphomagenesis and autoimmunity. Surprisingly, no overt systemic trade-offs or phenotypic alterations caused by partial suppression of nutrient signaling are seen in other organs, and RagCQ119L/+ mice show normal longevity and normal age-dependent health decline. These results support the efficacy and safety of moderate inhibition of nutrient signaling against pathological B cells.
Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.