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.
Department of Clinical Sciences, Institute of Liver Studies, King's College London School of Medicine, United Kingdom.
S
S
Yun
G J
GJ
Sawyer
X
X
Zhang
K
K
Gustafsson
J W
JW
Fabre
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