In Vivo Control of Diabetogenic T-Cells by Regulatory CD4+CD25+ T-Cells ExpressingFoxp3

Abstract

To understand the ability of regulatory T-cells to control diabetes development in clinically relevant situations, we established a new model of accelerated diabetes in young DP-BB rats by transferring purified T-cells from DR-BB rats made acutely diabetic. Transfer of 3, 5, 10, or 23 million pure in vitro؊activated T-cells accelerated diabetes onset in >90% of the recipients, with the degree of acceleration being dosage dependent. Cotransfer of unfractionated leukocytes from healthy donors prevented diabetes. Full protection was achieved when protective cells were transferred 3-4 days before diabetogenic cells, whereas transfer 2 days before conferred only partial protection. Protection resided in the CD4 ؉ fraction, as purified CD4 ؉ T-cells prevented the accelerated diabetes. When CD25 ؉ cells were depleted from these cells before they were transferred, their ability to prevent diabetes was impaired. CD25ϩ cells prevent Th1-and Th2-induced colitis as well as Leishmania major infection (10), control active experimental autoimmune encephalomyelitis (11), and ameliorate established colitis (12).In the NOD mouse model of human type 1 diabetes, regulatory T-cells were first defined as a subpopulation of cells expressing CD4 ϩ CD45RB low or CD4 ϩ CD62L ϩ (13-15). Later, these regulatory T-cells were shown to coexpress CD62L and CD25 (16).In the other spontaneous model of type 1 diabetes, the DP-BB, regulatory cells have not been characterized with regard to their expression of CD25. Previously, spontaneous disease was prevented by a single transfer of spleen cells (17) and the prevention was enhanced by enrichment for CD4 ϩ cells (18). However, transfer of leukocytes from normal rats has so far been successful only if the transfer takes place before the initiation of insulitis (i.e., at about age 1 month) (17,19); transfers conducted at 2 months accelerate diabetes (19). Protection is dependent on the engraftment of the ART2 ϩ (formerly RT6) cells (20); in the control strain, the DR-BB, depletion of these induces diabetes (21). We recently showed that accelerated diabetes induced by the transfer of in vitro phorbol myristate acetate (PMA) plus ionomycinϪactivated unfractionated splenocytes from acutely diabetic donors is delayed by transfer of DR-BBϪderived leukocytes (22).In this study, we proposed to prevent diabetes using a new rat model where diabetes onset was accelerated by transfer of pure, in vitro PMA plus ionomycinϪactivated T-cells; that is, without activated antigen-presenting cells as were used in our previous study (22). Using preactivated diabetogenic T-cells in the current study allowed us to explore a situation that is relevant to understanding how such already activated T-cells can be controlled in patients with ongoing ␤-cell destruction. Establishing the conditions required for preventing diabetes by cotransferring various leukocytes from healthy DR-BB rats allowed us to narrow a powerful regulatory potential to CD4 ϩ CD25 ϩ T-cells. This new model in rats is well suited to testing preventive s...

Evidence of a Functional Role for Mast Cells in the Development of Type 1 Diabetes Mellitus in the BioBreeding Rat

“…Although loss of Gimap5 does not impact the numbers of functional CD4 ϩ CD25 ϩ thymocytes, post-thymically these cells fail to thrive, rendering DR lyp/lyp animals deficient in this essential T cell subpopulation (13). The fact that DR lyp/lyp rats can be rescued through adoptive transfer of CD4 ϩ CD25 ϩ regulatory T cells (12,13) whereas depletion of these cells in the DR ϩ/ϩ induces disease (11) supports the possibility that T1DM disease progression in BB rats is dependent on the absence of T cell regulation. Whether CD4 ϩ CD25 ϩ T REG cells act upon mast cells and whether lack of such regulation is primary to diabetes progression remains unanswered.…”

“…Recently, adoptive transfer experiments of CD4 ϩ CD25 ϩ T regulatory (T REG ) cells to genetically lymphopenic BB or leukocytedepleted DR rats have been shown to rescue animals from T1DM, illustrating the importance of this T cell subpopulation in suppressing an autoimmunity to ␤ cells in this model (12,13). To better understand the immune processes before disease onset, we previously conducted gene expression profiling of whole pancreatic lymph nodes (PLN) of the DR lyp/lyp , DR ϩ/ϩ , and WF rats (14).…”

Protein/DNA vaccine‐induced antigen‐specific Treg confer protection against asthma

“…However, this situation becomes tenuous since such long-term treatment of recipients leads to their becoming immunocompromised and results in the loss of the ability to fight infections. The recent discovery of T-regulatory cells (Treg), including the naturally occurring thymus derived CD4 1 CD25 1 Treg has been an important advance in knowledge concerning the regulation of immune responses [13][14][15][16]. Adaptive Tr1 and mucosal-induced Th3 cells and antigen-induced CD4 1 CD25 À Treg have been proposed to be used as immuno-regulators of auto-reactive pathogenesis [17][18][19].…”

Autoimmunity and Immunotherapy of Type 1 Diabetes

“…(Chen et al, 2005c;Hong et al, 2001;Rewers & Gottlieb, 2009). Although most of the immunomodulator treatments induce Treg cells activation, the direct infusion of ex vivo-expanded regulatory T cells has been considered to be a potential to prevent T1D (Lundsgaard et al, 2005;Tang et al, 2004;Tarbell et al, 2004) as well as other diseases, such as systemic lupus erythematosus (SLE) (Zheng et al, 2004), multiple sclerosis (MS) (Kohm et al, 2002) and inflammatory bowel disease (IBD) (Mottet et al, 2003). Tregbased cell therapy must meet at least four important therapeutic criteria: to (1) avoid the induction of immunogenicity of the infused cells; (2) prevent or delay cellular immunosenescence; (3) maximize help; and (4) be cognizant of the known differences between mouse and human T-cell biology (June & Blazar, 2006).…”