Adoptive Transfer of Dendritic Cells Expressing Fas Ligand Modulates Intestinal Inflammation in a Model of Inflammatory Bowel Disease.
BACKGROUND
Inflammatory bowel diseases (IBD) are chronic relapsing inflammatory conditions of unknown cause and likely result from the loss of immunological tolerance, which leads to over-activation of the gut immune system. Gut macrophages and dendritic cells (DCs) are essential for maintaining tolerance, but can also contribute to the inflammatory response in conditions such as IBD. Current therapies for IBD are limited by high costs and unwanted toxicities and side effects. The possibility of reducing intestinal inflammation with DCs genetically engineered to over-express the apoptosis-inducing FasL (FasL-DCs) has not yet been explored.


OBJECTIVE
Investigate the immunomodulatory effect of administering FasL-DCs in the rat trinitrobenzene sulfonic acid (TNBS) model of acute colitis.


METHODS
Expression of FasL on DCs isolated from the mesenteric lymph nodes (MLNs) of normal and TNBS-colitis rats was determined by flow cytometry. Primary rat bone marrow DCs were transfected with rat FasL plasmid (FasL-DCs) or empty vector (EV-DCs). The effect of these DCs on T cell IFNγ secretion and apoptosis was determined by ELISPOT and flow cytometry for Annexin V, respectively. Rats received FasL-DCs or EV-DCs intraperitoneally 96 and 48 hours prior to colitis induction with TNBS. Colonic T cell and neutrophil infiltration was determined by immunohistochemistry for CD3 and myeloperoxidase activity assay, respectively. Macrophage number and phenotype was measured by double immunofluorescence for CD68 and inducible Nitric Oxide Synthase.


RESULTS
MLN dendritic cells from normal rats expressed more FasL than those from colitic rats. Compared to EV-DCs, FasL-DCs reduced T cell IFNγ secretion and increased T cell apoptosisin vitro. Adoptive transfer of FasL-DCs decreased macroscopic and microscopic damage scores and reduced colonic T cells, neutrophils, and proinflammatory macrophages when compared to EV-DC adoptive transfer.


CONCLUSIONS
FasL-DCs are effective at treating colonic inflammation in this model of IBD and represent a possible new treatment for patients with IBD.
Ponce Health Sciences University-Medical School and Ponce Research Institute, Ponce, PR 00732, USA; Department of Biology, University of Puerto Rico - Ponce Campus, Ponce, PR 00732, USA.
Edelmarie Rivera
ER
de Jesus
Ponce Health Sciences University-Medical School and Ponce Research Institute, Ponce, PR 00732, USA.
Raymond A
RA
Isidro
Ponce Health Sciences University-Medical School and Ponce Research Institute, Ponce, PR 00732, USA.
Myrella L
ML
Cruz
Ponce Health Sciences University-Medical School and Ponce Research Institute, Ponce, PR 00732, USA.
Harry
H
Marty
Ponce Health Sciences University-Medical School and Ponce Research Institute, Ponce, PR 00732, USA.
Caroline B
CB
Appleyard
Adoptive transfer; Dendritic cells; FasL (CD95L); Inflammatory bowel disease; Macrophages