Specific suppression of interleukin 2 biosynthesis by synthetic antisense oligodeoxynucleotides does not influence allograft rejection.
BACKGROUND
Interleukin (IL)-2 supplementation can reverse both blood transfusion-induced tolerance to kidney allografts and spontaneous tolerance to liver allografts in rats. Moreover, IL-2 expression is frequently suppressed in models of allograft tolerance. The failure of IL-2 biosynthesis might therefore play a critical role in tolerance induction.


METHODS
Three antisense oligodeoxynucleotides (AS-1, AS-2, AS-3) to rat IL-2, and a control oligo (C-1) consisting of a scrambled version of AS-1, were evaluated for gene-specific suppression of IL-2 biosynthesis in vitro and in vivo, and for their effects on kidney allograft survival. Reverse transcriptase-polymerase chain reaction and IL-2 protein assays were used to assay concanavalin A-driven IL-2 biosynthesis by lymph node lymphocytes in vitro. PVG recipients of Dark Agouti kidney allografts were treated with the oligos. Graft survival and IL-2 biosynthesis by reverse transcriptase-polymerase chain reaction in spleen and graft biopsy specimens were assessed.


RESULTS
The AS-1 oligo, but not the AS-2, AS-3 or C-1 oligos, suppressed concanavalin A-driven IL-2 biosynthesis for the 4 days of culture. This effect was dependent on delivery of the AS-1 oligo with lipofectamine. Supplementation with exogenous IL-2 reversed the suppression of lymphocyte proliferation in AS-1-treated cultures. Administration of AS-1 intravenously at 10 mg/kg/day to PVG recipients of Dark Agouti kidney allografts suppressed IL-2 (but not IL-6, interferon-gamma, or tumor necrosis factor-alpha) synthesis in the grafts of seven of nine rats, as measured in biopsy specimens taken at days 2-7. By contrast, all nine control grafts strongly expressed IL-2. However, neither graft histopathology nor graft survival was affected.


CONCLUSIONS
Antisense oligonucleotides can powerfully suppress IL-2 biosynthesis in vitro and in allograft recipients in vivo, but this does not affect kidney allograft rejection.
Yun
S
S
Department of Clinical Sciences, Institute of Liver Studies, King's College London School of Medicine, United Kingdom.
Sawyer
G J
GJ
Zhang
X
X
Gustafsson
K
K
Fabre
J W
JW
D000818:Animals; D002411:Cation Exchange Resins / Q000494:pharmacology / Q000633:toxicity; D006084:Graft Rejection; D007376:Interleukin-2 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D016030:Kidney Transplantation / Q000276:immunology*; D008055:Lipids / Q000494:pharmacology / Q000633:toxicity; D008213:Lymphocyte Activation / Q000187:drug effects; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D014184:Transplantation, Homologous
D002411:Cation Exchange Resins; D007376:Interleukin-2; D008055:Lipids; C086724:Lipofectamine; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger