Eosinophils are not required for the rejection of neovascularized fetal pig proislet xenografts in mice.
The rejection of neovascularized pig proislet (islet precursor) xenografts in mice is a CD4 T cell-dependent process involving invasion of the graft site mainly by host CD4 T cells and eosinophils. We previously identified CD4 T cell-dependent enhancement of intragraft IL-3, IL-4, and IL-5 mRNA expression during acute xeno-rejection in CBA/H recipient mice. In the present study we investigated the role of each cytokine and the involvement of eosinophils in the rejection of pig proislet xenografts using cytokine gene knockout mice (IL-4 -/- and IL-5 -/-) and the treatment of transplant recipients with anti-IL-3 mAb. In IL-4 -/- mice, IL-5 -/- recipient animals, and anti-IL-3 mAb-treated CBA/H mice, eosinophil accumulation at the transplant site was inhibited or ablated, but the kinetics of xenograft rejection was unaltered. Prolonged xenograft survival was only achieved in anti-CD4 mAb-treated mice and consistently correlated with the absence of intragraft IL-3, IL-4, and IL-5 mRNA enhancement. Together these findings indicate that neither IL-3, nor IL-4, nor IL-5 individually plays an obligatory role in the rejection process. The cytokine mRNA profile correlating with the lack of eosinophil recruitment was variable; the data suggest that IL-4 regulates eosinophil involvement in the xeno-rejection reaction indirectly via effects on IL-5 and IL-3 transcript expression. There is also suggestive evidence that IL-5 may influence IL-3 and IL-4 mRNA expression via feedback inhibition. Eosinophils, therefore, do not play an essential role in the rejection of neovascularized pig proislet xenografts in mice.
Simeonovic
C J
CJ
The John Curtin School of Medical Research, The Australian National University, Canberra, Australia.
Townsend
M J
MJ
Wilson
J D
JD
McKenzie
K U
KU
Ramsay
A J
AJ
Matthaei
K I
KI
Mann
D A
DA
Young
I G
IG
D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D015704:CD4 Antigens / Q000276:immunology; D016207:Cytokines / Q000235:genetics; D004804:Eosinophils / Q000276:immunology*; D006084:Graft Rejection / Q000235:genetics / Q000503:physiopathology* / Q000628:therapy; D006085:Graft Survival / Q000235:genetics; D007377:Interleukin-3 / Q000276:immunology; D007515:Islets of Langerhans / Q000098:blood supply* / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000276:immunology* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D018345:Mice, Knockout; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000276:immunology* / Q000628:therapy; D012333:RNA, Messenger / Q000096:biosynthesis; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000378:metabolism; D013552:Swine; D014158:Transcription, Genetic / Q000276:immunology; D014183:Transplantation, Heterologous
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D016207:Cytokines; D007377:Interleukin-3; D012333:RNA, Messenger