title: Antigen sampling on the Peyer's patches in a murine small bowel transplantation model.
abstract: OBJECTIVE
  This study investigated changes in the mucosal barrier of transplanted intestines with particular emphasis on antigen sampling by Peyer's patches (PPs).
  
  
  METHODS
  Heterotopic small bowel transplantation (SBTx) was performed as described previously. C57BL/6 mice were used as donors and BALB/c (allogeneic) or C57BL/6 mice (syngeneic) as recipients. Tacrolimus (FK506) or saline control was administered to the recipients for 2 weeks. Four groups included in this study were: syngeneic with or without immunosuppression (SYN and SYN + FK506, respectively) and allogeneic with or without immunosuppression (ALLO and ALLO + FK506, respectively). Animals were sacrificed weekly after SBTx to evaluate microfold (M) cells within PPs and for routine histology. By the third postoperative week, recipients were subjected to an intestine loop model to examine the uptake of microbeads by M cells as well as expression of Toll-like receptor 2 (TLR2) protein in the PPs with or without a TLR2 agonist challenge. We also measured occludin expression on follicle-associated epithelium (FAE) of PPs in the grafts.
  
  
  RESULTS
  Transportation of microbeads through the PPs of the grafts increased in the ALLO + FK506 group compared with that in the SYN or SYN + FK506 group. This finding was accompanied by increased expression of TLR2 in the PPs and a gradually increased number of M cells following SBTx. However, occludin expression patterns on the FAE of the PPs in the grafts were similar among SYN, SYN + FK506, and ALLO + FK506 groups. Nevertheless, as transportation of microbeads and TLR2 expression in the PPs of the grafts was enhanced once exposed to Pam3Cys-SKKKK, similar results were not seen in the ALLO + FK506 group.
  
  
  CONCLUSIONS
  Our study revealed that the mucosal barrier of intestinal grafts is altered under alloreactivity as evidenced by enhanced antigen sampling. Such a change may provide a pathway for translocation of microorganisms in the lumen.
authors.affiliation: Nanjing University School of Medicine, Research Institute of General Surgery, Jinling Hospital, Nanjing, China.
authors.forename: X
authors.initials: X
authors.lastname: Ping
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D000941:Antigens / Q000378:metabolism*; D018988:Bacterial Translocation; D015153:Blotting, Western; D005260:Female; D005455:Fluorescent Antibody Technique; D007082:Ileum / Q000276:immunology / Q000378:metabolism / Q000637:transplantation* / Q000648:ultrastructure; D018928:Immunity, Mucosal; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism / Q000637:transplantation* / Q000648:ultrastructure; D008074:Lipoproteins / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D062793:Occludin; D010539:Permeability; D010581:Peyer's Patches / Q000276:immunology / Q000378:metabolism / Q000637:transplantation* / Q000648:ultrastructure; D016559:Tacrolimus / Q000008:administration & dosage; D013997:Time Factors; D051195:Toll-Like Receptor 2 / Q000819:agonists / Q000378:metabolism; D016042:Transplantation, Heterotopic
chemical_list: D000941:Antigens; D007166:Immunosuppressive Agents; D008074:Lipoproteins; D008565:Membrane Proteins; D062793:Occludin; C568986:Ocln protein, mouse; C493486:Tlr2 protein, mouse; D051195:Toll-Like Receptor 2; C061108:N-palmitoyl-S-(2,3-bis(palmitoyloxy)propyl)cysteinyl-seryl-lysyl-lysyl-lysyl-lysine; D016559:Tacrolimus