Influence of Vitamin C on the differentiation and functional plasticity of human gamma delta T cells

Gamma delta (gd) T cells are a numerically small subset of CD3+ T cells in human peripheral blood. They have recently attracted substantial interest as effector cells for cellular immunotherapy, due to their MHC-independent recognition and lysis of many solid tumor and leukemia/lymphoma cells. Depending on the micro-environmental cues, gd T cells also produce Th1/Th2/Th9/Th17-type cytokines, process and present antigen to conventional T cells, and can acquire regulatory activity. Potential clinical applications of in vitro expanded human gd T cells include the adoptive transfer into cancer patients. gdT cells can use different mechanisms to exert their effector functions. However, a better understanding of how their functional plasticity can be modulated is required to improve their translational efficacy. In this regard, it is important to develop novel strategies to optimize the culture conditions enabling maximal proliferative and functional activity. Vitamin C (L-ascorbic acid) is an essential vitamin that has to be supplied through appropriate nutrition or dietary sources. Vitamin C plays important roles in many different biological processes, spanning from stem cell differentiation to cancer cell biology. Moreover, Vitamin C has multiple effects on immune cells, acts as cofactor for several enzymes, has antioxidant activity and is known as facilitator of DNA hydroxymethylation through its capacity to enhance the capacity of Ten-eleven-translocation enzymes. The goal of the present thesis was to analyze the influence of the more stable derivative of Vitamin C, L-ascorbic 2-phosphate (pVC) on the differentiation and effector functions of human gd T cells. Moreover, the mechanisms sustaining pVC-mediated gd T-cell differentiation were also investigated. The first part of this thesis studied the effect of pVC on the proliferation, differentiation and cytotoxic effector function. The results demonstrated that supplementation of pVC to the in vitro expanded human gd T cells significantly enhances their proliferative expansion. Further investigations demonstrated that pVC does not prevent activation-induced death of (phospho)antigen-re-stimulated gd T cells but rather enhances cell cycle progression and thereby cellular expansion. Moreover, pVC sustained the polarization of expanded gd T cells towards a mixed Th1+2-like phenotype along with the expression of Th1 and Th2 signature cytokines. Finally, we observed that the cytotoxicity of the in vitro expanded gd T cells against pancreatic cancer cell lines was enhanced in the presence of pVC and was associated with an increased release of IFN-gamma. In the second part, this thesis investigated the effect of pVC on the TGF-beta-induced expression of the regulatory T-cell-specific transcription factor Foxp3 and the resulting regulatory activity of purified human Vg9Vd2 T cells. pVC induced a significant increase of TGF-beta-induced Foxp3 expression (both at protein and transcriptional levels) and stability as well as an increase in suppressive activity in vitro. Methylation analysis of the Treg-specific demethylated region (TSDR) revealed that the TGF-b-expanded gd T cells treated with pVC showed a more pronounced demethylation of FOXP3. The third pillar of this thesis addressed the influence of pVC on the genome-wide gene expression and DNA methylation of human gd T cells activated for eight days in vitro. At this time point, pVC had only minor effects on the transcriptome and genome-wide DNA methylation of the expanded gd T cells. Taken together, the results of this thesis demonstrated that Vitamin C has a significant influence on the functional activity of human gd T cells and thus appears to be suitable for enhancing the effector function of gd T cells for adoptive cell transfer in cancer patients. In addition, Vitamin C may also enhance the regulatory activity of gd T cells (in the presence of TGF-beta), which may be of interest in the context of autoimmune diseases

Human Breast Milk: From Food to Active Immune Response With Disease Protection in Infants and Mothers

Breastfeeding is associated with long-term wellbeing including low risks of infectious diseases and non-communicable diseases such as asthma, cancer, autoimmune diseases and obesity during childhood. In recent years, important advances have been made in understanding the human breast milk (HBM) composition. Breast milk components such as, non-immune and immune cells and bioactive molecules, namely, cytokines/chemokines, lipids, hormones, and enzymes reportedly play many roles in breastfed newborns and in mothers, by diseases protection and shaping the immune system of the newborn. Bioactive components in HBM are also involved in tolerance and appropriate inflammatory response of breastfed infants if necessary. This review summarizes the current literature on the relationship between mother and her infant through breast milk with regard to disease protection. We will shed some light on the mechanisms underlying the roles of breast milk components in the maintenance of health of both child and mother

Vitamin C, From Supplement to Treatment: A Re-Emerging Adjunct for Cancer Immunotherapy?

Vitamin C (VitC), in addition to its role as a general antioxidant, has long been considered to possess direct anti-cancer activity at high doses. VitC acts through oxidant and epigenetic mechanisms, which at high doses can exert direct killing of tumor cells in vitro and delay tumor growth in vivo. Recently, it has also been shown that pharmacologic-dose VitC can contribute to control of tumors by modulating the immune system, and studies have been done interrogating the role of physiologic-dose VitC on novel adoptive cellular therapies (ACTs). In this review, we discuss the effects of VitC on anti-tumor immune cells, as well as the mechanisms underlying those effects. We address important unanswered questions concerning both VitC and ACTs, and outline challenges and opportunities facing the use of VitC in the clinical setting as an adjunct to immune-based anti-cancer therapies

Total Immunoglobulin Y Detection in Avian Malaria-infected Domestic Birds from Uganda

Background and Aim: The use of microscopy-based and polymerase chain reaction (PCR)-based methods have offered considerable insights in detecting avian blood malaria infection in domestic and wild birds. The infection has a significant impact on the immunity of birds. However, some observations concerning the role of immune system in controlling the infection continue to question the extent of immune factors involved. To address this, the current study hypothesized that avian malaria infection may influence the humoral response of domestic birds. Materials and Methods: The prevalence of avian malaria parasites (both Plasmodium and Haemoproteus spp.) in free-ranging domestic birds from Uganda was evaluated using PCR and the level of Immunoglobulin Y (IgY) antibody in malaria-infected and uninfected birds was determined using enzyme-linked immunosorbent assay (ELISA). Result: The results showed that 10 (15.15%) of 66 individually tested birds were infected with avian malaria parasites. Interestingly, an increase in the level of IgY associated with the infection was found. Of note, the uninfected birds exhibited a consistent level of IgY, however, less than in malaria-positive birds. It is likely that avian malaria-independent factors may have been involved in this induction in uninfected birds. Conclusion: The data obtained in this study suggest that avian malaria infections influence the production of IgY in domestic birds, therefore indicating the potential of IgY as an immune biomarker for screening avian malaria infection in domestic birds. However, these observations are subject to further investigation with larger sample size.Rufford Small Grants (RSG

Immunotherapy With Human Gamma Delta T Cells—Synergistic Potential of Epigenetic Drugs?

Epigenetics has emerged as one of the fastest growing concepts, adding more than 45 new publications every day, spreading through various fields ( 1). Conrad Waddington coined the term “epigenetics” in 1942; however, a multitude of definitions has been endorsed by different researchers. In essence, Waddington’s definition of “epigenetics” and its redefinition by Holiday is at the heart of cellular function. Hence, it is obvious that epigenetic regulation plays a central role also in the specification, differentiation, and functional plasticity of T lymphocytes ( 2). T-cell fate decision in progenitor cells, functional CD4 T-cell plasticity, CD8 T-cell differentiation, but also T-cell memory, are all substantially governed by epigenetic mechanisms (3–7). Here, we focus on the current development of drugs targeting major pathways of epigenetic regulation and their possible impact on γδ T-cell multifunctionality. We aim to develop concepts of how some of these approaches might help to improve the efficacy of γδ T-cell-based immunotherapies

Human Breast Milk: From Food to Active Immune Response With Disease Protection in Infants and Mothers

Breastfeeding is associated with long-term wellbeing including low risks of infectious diseases and non-communicable diseases such as asthma, cancer, autoimmune diseases and obesity during childhood. In recent years, important advances have been made in understanding the human breast milk (HBM) composition. Breast milk components such as, non-immune and immune cells and bioactive molecules, namely, cytokines/chemokines, lipids, hormones, and enzymes reportedly play many roles in breastfed newborns and in mothers, by diseases protection and shaping the immune system of the newborn. Bioactive components in HBM are also involved in tolerance and appropriate inflammatory response of breastfed infants if necessary. This review summarizes the current literature on the relationship between mother and her infant through breast milk with regard to disease protection. We will shed some light on the mechanisms underlying the roles of breast milk components in the maintenance of health of both child and mother

Human Breast Milk: From Food to Active Immune Response With Disease Protection in Infants and Mothers

Breastfeeding is associated with long-term wellbeing including low risks of infectious diseases and non-communicable diseases such as asthma, cancer, autoimmune diseases and obesity during childhood. In recent years, important advances have been made in understanding the human breast milk (HBM) composition. Breast milk components such as, non-immune and immune cells and bioactive molecules, namely, cytokines/chemokines, lipids, hormones, and enzymes reportedly play many roles in breastfed newborns and in mothers, by diseases protection and shaping the immune system of the newborn. Bioactive components in HBM are also involved in tolerance and appropriate inflammatory response of breastfed infants if necessary. This review summarizes the current literature on the relationship between mother and her infant through breast milk with regard to disease protection. We will shed some light on the mechanisms underlying the roles of breast milk components in the maintenance of health of both child and mother

Vitamin C supports conversion of human γδ T cells into FOXP3-expressing regulatory cells by epigenetic regulation.

Human γδ T cells are potent cytotoxic effector cells, produce a variety of cytokines, and can acquire regulatory activity. Induction of FOXP3, the key transcription factor of regulatory T cells (Treg), by TGF-β in human Vγ9 Vδ2 T cells has been previously reported. Vitamin C is an antioxidant and acts as multiplier of DNA hydroxymethylation. Here we have investigated the effect of the more stable phospho-modified Vitamin C (pVC) on TGF-β-induced FOXP3 expression and the resulting regulatory activity of highly purified human Vγ9 Vδ2 T cells. pVC significantly increased the TGF-β-induced FOXP3 expression and stability and also increased the suppressive activity of Vγ9 Vδ2 T cells. Importantly, pVC induced hypomethylation of the Treg-specific demethylated region (TSDR) in the FOXP3 gene. Genome-wide methylation analysis by Reduced Representation Bisulfite Sequencing additionally revealed differentially methylated regions in several important genes upon pVC treatment of γδ T cells. While Vitamin C also enhances effector functions of Vγ9 Vδ2 T cells in the absence of TGF-β, our results demonstrate that pVC potently increases the suppressive activity and FOXP3 expression in TGF-β-treated Vγ9 Vδ2 T cells by epigenetic modification of the FOXP3 gen