Biology subjects

Boccia, T.

Publications and source records attributed to Boccia, T..

3 recordsLinked to original sources

bioRxiv2025

Group 2 Innate lymphoid cells promote allograft survival by constraining and inducing anergy in alloreactive CD4+ T cells

Although solid organ transplant outcomes have dramatically improved over the last several decades, incomplete understanding of the immune interface between the donor organ and the recipients immune system has impaired our ability to induce immune tolerance in most transplant recipients. Since group 2 innate lymphoid cells (ILC2s) reside in all transplanted solid organs, participate in wound healing, and coordinate other immunoregulatory cell populations, we investigated their role in the alloimmune response. Using a mouse heterotopic cardiac transplant model, we show that recipient ILC2s replace donors ILC2s, upregulate MHCII without expressing costimulatory molecules. In addition, recipient derived ILC2s process and present alloantigen, inducing CD4+ T cell anergy via Caspase-3 pathway. When recipient-derived ILC2s are not present, we observed a significant increase in infiltrating donor reactive CD4+ T cells and worsened allograft survival. Additionally, expansion of ILC2s in vivo through IL33 administration prolonged the survival of murine heart allografts. Overall, these data highlight a critical and novel immunoregulatory role of host-derived ILC2s in solid organ transplant, where they induce anergy in alloreactive CD4+ T cells, promoting the induction of alloimmune tolerance.

immunology↗

bioRxiv2025

Adjuvant conditioning enhances neutrophil function while inducing a suppressive peritoneal macrophage phenotype

Adjuvants are widely used to boost the immune response during vaccination protocols. Our group has previously reported that repeated intraperitoneal administration of alum in mice, known as adjuvant conditioning (AC), creates an immunosuppressive environment that delays allogeneic graft rejection through NLRP3-dependent MDSC expansion. However, little is known about the effects of AC on the reprogramming of peritoneal cavity cells, particularly the different peritoneal macrophage populations and the effects in the adaptive immune response. We found a population-specific immune response to alum, with small peritoneal macrophages (SPMs) being more prone to inflammasome activation than large peritoneal macrophages (LPMs) in vitro. In vivo, alum exposure led to NLRP3-dependent macrophage disappearance reaction (MDR) of LPMs, which could be explained by aggregate formation and migration to the omentum. AC also induced the reprogramming of resident macrophages and infiltrating monocytes towards a less inflammatory state, making them more vulnerable to bacterial infections, but recruited neutrophils with enhanced killing ability. This suggests that AC may influence both innate and adaptive immunity in distinct ways, reprogramming cells to different profiles, indicating its potential as an immunosuppressive treatment for autoimmune diseases and transplant rejection.

immunology↗

bioRxiv2024

Adjuvant conditioning shapes the adaptive immune response and promotes trained immunotolerance via NLRP3/IL-1

Trained immunity enhances responsiveness of the innate immune system upon restimulation. Although adjuvants are used to enhance immune responses, we showed that repeated administration of alum, termed adjuvant conditioning (AC), establishes an immunosuppressive environment that delays allogeneic graft rejection by expanding myeloid-derived suppressor cells (MDSCs). Here, we show that AC-induced MDSCs suppress antigen specific adaptive responses both in vitro and in vivo, and that the immunosuppression is abolished in the absence of NLRP3 and IL-1 signaling. Allogeneic pancreatic islets transplanted into AC-treated NLRP3-/- mice are not protected, demonstrating that AC requires NLRP3 signaling. Finally, AC also has an immunosuppressive effect on human cells. Overall, our data show that AC establishes an immunosuppressive milieu via the NLRP3/IL-1 axis, leading to trained immunosuppression, or trained tolerance. Our findings give a potent mandate to explore the possibility to target the NLRP3/IL-1 pathway as a new promising strategy to condition transplant recipients and promote allograft tolerance.

immunology↗