Biology subjects

Wohlfert, E.

Publications and source records attributed to Wohlfert, E..

4 recordsLinked to original sources

bioRxiv2026

Lysophosphatidylserine Nanoparticles Induce Oral Tolerance Independent of TIM-4 and Canonical PS Processing

Protein replacement therapy is highly effective for treating many protein-deficiency disorders, but its long-term clinical benefit is often limited by anti-drug antibody responses that neutralize therapeutic proteins, compromising safety and efficacy. To address these unwanted immune responses, a lipid nanoparticle-based immunotherapy platform has been developed to induce antigen-specific tolerance. Mice treated with antigen associated with either double-chain phosphatidylserine (PS) or lysophosphatidylserine (LysoPS), a single-acyl-chain phospholipid, showed reduced antibody titers following subcutaneous pre-exposure. However, only LysoPS nanoparticles induced tolerance after oral administration, suggesting structural differences between PS and LysoPS can impact tolerogenic potential, depending on the site of delivery. As an apoptotic "eat-me" signal, PS is recognized by phagocytic receptors such as TIM-4 and is associated with LC3-associated phagocytosis. These nanoparticles have been hypothesized to promote apoptotic mimicry to regulate immunity. However, the contribution of TIM-4 to oral tolerance remains unclear. Here, we investigated the role of TIM-4 in LysoPS-mediated oral tolerance using a knockout mouse model. Our data showed that TIM-4-/- mice induced tolerance to ovalbumin encapsulated in LysoPS comparable to that of wild-type mice. We also found that LysoPS nanoparticles did not follow the same surface engagement and intracellular trafficking pathways as PS nanoparticles. These results reveal that, despite sharing the same headgroup, differences in acyl chain number critically shape nanoparticle-immune cell interactions and provide a mechanistic framework that may explain the unique ability of LysoPS nanoparticles to induce oral tolerance.

immunology↗

bioRxiv2025

Neutrophils induce effective antibody responses to the pneumococcal conjugate vaccine by inhibiting regulatory T cells

Neutrophils are required for production of protective antibodies in response to the pneumococcal conjugate vaccine (PCV), however, the mechanisms behind that are not known. Here, in exploring mechanisms, we found that depletion of neutrophils at the time of vaccination in female mice led to increased regulatory T cells (Tregs) in the spleen that was accompanied by a dysregulated cytokine environment. Following vaccination, neutrophils homed into secondary lymphoid organs where they increased expression of T cell engaging/inhibiting markers. Depletion of Tregs in neutrophil deficient mice restored antibody function against pneumococcal infection. Importantly, PCV vaccination of human female participants altered neutrophil phenotype and in vitro coculture of donor neutrophils with PBMCs at one week following vaccination resulted in lower percentage and proliferation of FOXP3+ T cells, showing the clinical relevance of this phenotype. This work reveals a new mechanism by which neutrophils ensure protective antibody responses to vaccination by suppressing Tregs.

immunology↗

bioRxiv2023

Ets1 and IL17RA cooperate to regulate autoimmune responses as well as skin immunity to Staphylococcus aureus

Ets1 is a lymphoid-enriched transcription factor that regulates B and T cell functions in development and disease. Mice that lack Ets1 (Ets1 KO) develop spontaneous autoimmune disease with high levels of autoantibodies. Naive CD4+ T cells isolated from Ets1 KO mice differentiate more readily to Th17 cells that secrete IL-17, a cytokine implicated in autoimmune disease pathogenesis. To determine if increased IL-17 production contributes to the development of autoimmunity in Ets1 KO mice, we crossed Ets1 KO mice to mice lacking the IL-17 receptor A subunit (IL17RA KO) to generate double knock out (DKO) mice. We found that the absence of IL17RA signaling did not prevent or ameliorate the autoimmune phenotype of Ets1 KO mice, but rather that DKO animals exhibited worse symptoms with striking increases in activated B cells and secreted autoantibodies. This was correlated with a prominent increase in the numbers of T follicular helper (Tfh) cells. In addition to the autoimmune phenotype, DKO mice also showed signs of immunodeficiency and developed spontaneous skin lesions colonized by Staphylococcus xylosus. When DKO mice were experimentally infected with S. aureus they were unable to clear the bacteria, suggesting a general immunodeficiency to Staphylococcal species. {gamma}{delta} T cells are important for control of skin Staphylococcal infections. We found that mice lacking Ets1 have a complete deficiency of the {gamma}{delta} T cell subset dendritic epidermal T cells (DETC), which are involved in skin wound healing responses. To determine if loss of DETC might promote susceptibility to Staph infection, we depleted DETC from IL17RA KO mice and found that the combined loss of DETC and IL-17 signaling leads to a failure to clear the infection. Our studies suggest that defects in wound healing, such as that caused by loss of DETC, can cooperate with impaired IL-17 responses to lead to increased susceptibility to skin Staph infections.

immunology↗

bioRxiv2023

The Toxoplasma Oxygen Sensing Protein, TgPhyA, Is Required for Resistance to Interferon-gamma Mediated Nutritional Immunity

As Toxoplasma gondii disseminates through its host, the parasite must sense and adapt to its environment and scavenge nutrients. Oxygen (O2) is one such environmental factor and cytoplasmic prolyl 4-hydroxylases (PHDs) are evolutionarily conserved O2 cellular sensing proteins that regulate responses to changes in O2 availability. Toxoplasma expresses two PHDs. One of them, TgPHYa hydroxylates SKP1, a subunit of the SCF-E3 ubiquitin ligase complex. In vitro, TgPHYa is important for growth at low O2 levels. However, studies have yet to examine the role that TgPHYa or any other pathogen encoded PHD plays in virulence and disease. Using a type II ME49 Toxoplasma TgPHYa knockout, we report that TgPHYa is important for Toxoplasma virulence and brain cyst formation in mice. We further find that while TgPHYa mutant parasites can establish an infection in the gut they are unable to efficiently disseminate to peripheral tissues because the mutant parasites are unable to survive within recruited immune cells. Since this phenotype abrogated in IFN{gamma} knockout mice, we studied how TgPHYa mediates survival in IFN{gamma}-treated cells. We find that TgPHYa is not required for release of parasite-encoded effectors into host cells that neutralize anti-parasitic processes induced by IFN{gamma}. In contrast, we find that TgPHYa is required for the parasite to scavenge tryptophan, which is an amino acid whose levels are decreased after IFN{gamma} upregulates the tryptophan-catabolizing enzyme, indoleamine dioxygenase (IDO). We further find that relative to wild-type mice that IDO knockout mice display increased morbidity when infected with TgPHYa knockout parasites. Together, these data identify the first parasite mechanism for evading IFN{gamma}-induced nutritional immunity and highlight a novel role that oxygen sensing proteins play in pathogen growth and virulence.

microbiology↗