ICAM-1 Antisense Oligodeoxynucleotide Improves Islet Allograft Survival and Function

Abstract

Expression of intercellular adhesion molecule-1 (ICAM-1) and its ligand, leukocyte function antigen-1 (LFA-1), after pancreatic islet transplantation may affect both nonspecific and alloantigen-specific phases of graft destruction. We examined the effects of ICAM-1/LFA-1 blockade on the survival of islet allografts. Fresh C57BL/10 (H2 b ) pancreatic islets were transplanted under the renal subcapsular space (KC) or embolized into the liver after portal vein (PV) injection to C3H (H2 k ) mice. Recipients remained untreated or were treated for 7 days by IP administration of: ICAM-1 antisense phosphorothioate oligodeoxynucleotide (oligo) alone; anti-ICAM-1 (αICAM-1) monoclonal antibody (mAb) alone; αLFA-1 mAb alone; ICAM-1 oligo/αLFA mAb combination; αICAM-1 mAb/αLFA-1 mAb combination; or control oligo IP-8997 or IP-1082. In some experiments, donors were pretreated with ICAM-1 oligo. Inhibition of single ligand with 5.0 mg/kg ICAM-1 oligo (25.1 ± 10.3), 100 μg/daily αICAM-1 mAb (24.2 ± 8.0 days), or 50 μg/daily αLFA-1 mAb (42.8 ± 25.9 days) prolonged the survivals of KC islet allografts in comparison with untreated controls (11.9 ± 1.0 days; all p < 0.01). However, dual ICAM-1/LFA-1 blockade with either ICAM-1 oligo/αLFA-1 mAb (78.3 ± 16.5 days) or αICAM-1 mAb/αLFA-1 mAb (65.2 ±31.3 days) was the most effective therapy. Although pretreatment of donors with ICAM-1 oligo alone was ineffective (12.2 ± 0.8 days; NS), a combination of donor pretreatment and recipient treatment started 1 day prior to grafting with ICAM-1 oligo (39.2 ± 14.0 days) was more effective than the recipient treatment alone (24.6 ± 8.8 days). Furthermore, ICAM-1/LFA-1 blockade improved islet function as evaluated by glucose tolerance test, and decreased inflammation in comparison with untreated controls. Similar in vivo results were obtained following PV administration of islet allografts. Thus, ICAM-1/LFA-1 blockade prolongs the survival of pancreatic islet allografts and improves their early function.