Search

Introduction: Chimeric antigen receptor (CAR) expressing T-cells have shown great promise for the future of cancer immunotherapy with the recent clinical successes achieved in treating different hematologic cancers. Despite these early successes, several challenges remain in the field that require to be solved for the therapy to be more efficacious. One such challenge is the lack of long-term persistence of CD28 based CAR T-cells in patients. Although, CD28 based CAR T-cells elicit a robust acute anti-tumor response, they are more prone to early exhaustion, terminal differentiation and cell death due to their strong signaling patterns. Hence attenuation of signaling strength in CD28 based CARs is an accepted strategy to improve long-term CAR T-cell function and persistence in patients. Previous studies with the conventional T-cell receptor (TCR) have suggested that manipulation of CD3 immunoreceptor tyrosine-based activation motif (ITAM) sequences can alter TCR signaling strength. Based on these studies, we have designed 2 nd generation murine anti-CD19 CD28 based CARs with restricted CD3ζ ITAM sequence diversity while maintaining a multiplicity of three. They are called ζAAA, ζBBB and ζCCC based on which CD3ζ ITAM they express. The goal of the study is to understand the non-redundant signaling properties of the individual CD3ζ ITAMs and their effect on CAR T-cell function. We hypothesized that the individual CD3ζ ITAMs will exhibit unique signaling properties in the ITAM restricted CARs which may allow for optimization of CAR signaling and improve CAR T-cell persistence and function., Method: We subjected the ITAM restricted CAR T cells to various conditions of in vitro stimulation using CD19+ tumor cells or CD19-coated magnetic beads. Immunoblotting and flow cytometry based Ca2+ signaling assays were used to quantify signaling differences. Functional differences were studied using in vitro cytotoxicity, degranulation and cytokine expression assays. CAR T cell exhaustion and differentiation were studied using an in vitro exhaustion assay., Results: We observed that ζAAA CARs had stronger signaling strength compared to ζBBB and ζCCC CARs. The signaling differences were reflected in their functional activation profiles with T-cells expressing ζAAA CARs having a strong activation profile and ζCCC CARs having a weak activation profile. ζCCC CAR T cells were less prone to differentiation and exhaustion., Discussion: Since, weaker signaling ζCCC CARs favored less cell death, exhaustion and differentiation, they might be better candidates for improving long term survival and persistence of CAR T cells in patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2025 Majumdar, Echelibe, Bettini and Bettini.)

As the prevalence of allergy and autoimmune disease in industrialized societies continues to rise, improving our understanding of the mechanistic roles behind microbiota-immune homeostasis has become critical for informing therapeutic interventions in cases of dysbiosis. Of particular importance, are alterations to intestinal microbiota occurring within the critical neonatal window, during which the immune system is highly vulnerable to environmental exposures. This review will highlight recent literature concerning mechanisms of early-life microbiota-immune homeostasis as well as discuss the potential for therapeutics in restoring dysbiosis in early life., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2023 Reynolds and Bettini.)

Type-1 Diabetes (T1D) is a complex polygenic autoimmune disorder involving T-cell driven beta-cell destruction leading to hyperglycemia. There is no cure for T1D and patients rely on exogenous insulin administration for disease management. T1D is associated with specific disease susceptible alleles. However, the predisposition to disease development is not solely predicted by them. This is best exemplified by the observation that a monozygotic twin has just a 35% chance of developing T1D after their twin's diagnosis. This makes a strong case for environmental triggers playing an important role in T1D incidence. Multiple studies indicate that commensal gut microbiota and environmental factors that alter their composition might exacerbate or protect against T1D onset. In this review, we discuss recent literature highlighting microbial species associated with T1D. We explore mechanistic studies which propose how some of these microbial species can modulate adaptive immune responses in T1D, with an emphasis on T-cell responses. We cover topics ranging from gut-thymus and gut-pancreas communication, microbial regulation of peripheral tolerance, to molecular mimicry of islet antigens by microbial peptides. In light of the accumulating evidence on commensal influences in neonatal thymocyte development, we also speculate on the link between molecular mimicry and thymic selection in the context of T1D pathogenesis. Finally, we explore how these observations could inform future therapeutic approaches in this disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Majumdar, Lin and Bettini.)

The strongest susceptibility allele for Type 1 Diabetes (T1D) is human leukocyte antigen (HLA), which supports a central role for T cells as the drivers of autoimmunity. However, the precise mechanisms that allow thymic escape and peripheral activation of beta cell antigen-specific T cells are still largely unknown. Studies performed with the non-obese diabetic (NOD) mouse have challenged several immunological dogmas, and have made the NOD mouse a key experimental system to study the steps of immunodysregulation that lead to autoimmune diabetes. The structural similarities between the NOD I-A g7 and HLA-DQ8 have revealed the stability of the T cell receptor (TCR)/HLA/peptide tri-molecular complex as an important parameter in the development of autoimmune T cells, as well as afforded insights into the key antigens targeted in T1D. In this review, we will provide a summary of the current understanding with regard to autoimmune T cell development, the significance of the antigens targeted in T1D, and the relationship between TCR affinity and immune regulation.