Diabetes, Vol 47, Issue 9 1399-1405, Copyright © 1998 by American Diabetes Association
Long-term survival of segmental pancreas isografts in NOD/Lt mice treated with anti-CD4 and anti-CD8 monoclonal antibodies
PL Mottram, LJ Murray-Segal, W Han, J Maguire, A Stein-Oakley and TE Mandel
Department of Surgery, Royal Melbourne Hospital, Parkville, Victoria, Australia. p.mottram@medicine.unimelb.edu.au
Spontaneously diabetic nonobese diabetic (NOD/Lt) mice were treated with
anti-T-cell monoclonal antibodies (mAbs) at the time of grafting with
vascularized segmental pancreas isografts. Recipients were either untreated
or given anti-CD4 and/or anti-CD8 mAbs (0.5 mg/20-g mouse on each of 4
consecutive days), which reduced target cell levels to <5% of normal.
Graft function was monitored by measuring blood glucose (BG) levels.
Transplants were removed for histological examination when BG returned to
>20 mmol/l for two consecutive readings. Isografts from 3- to 4-week-old
prediabetic mice placed in untreated diabetic NOD mice ceased functioning
in 9-13 days with a mean survival time (MST) +/- SD of 10 +/- 2. Treatment
with anti-CD4 prolonged survival significantly (MST = 61 +/- 35 days, P
< 0.05 compared with untreated control mice). Anti-CD8 treatment was
less effective, but it still significantly improved graft survival (MST =
24 +/- 9 days, P < 0.05 compared with untreated control mice). Anti-CD8
plus anti-CD4 treatment was highly effective in inhibiting autoimmune
destruction of the grafts (MST = 97 +/- 8 days). This clearly demonstrates
that transient inactivation of most T-cells with anti-CD4 plus anti-CD8
mAbs effectively controls autoimmune disease in the isograft, despite
recovery of CD4 and CD8 T-cells to normal levels. Although insulitis
developed in the long-term grafts, insulitis scores did not increase
between 33 and 100 days, and none of the mice progressed to IDDM in 100
days. Histology showed a predominantly peri-islet T-cell and macrophage
infiltrate with ductal expression of the cytokines interleukin (IL)-4,
IL-2, and interferon-gamma. There was little infiltrate or expression of
cytokines within the islets. Thus, mAb treatment at the time of grafting
allowed isograft survival and prevented progression from insulitis to
beta-cell destruction.