Diabetes, Vol 49, Issue 12 1998-2006, Copyright © 2000 by American Diabetes Association
Suppression and acceleration of autoimmune diabetes by neutralization of endogenous interleukin-12 in NOD mice
K Fujihira, M Nagata, H Moriyama, H Yasuda, K Arisawa, M Nakayama, S Maeda, M Kasuga, K Okumura, H Yagita and K Yokono
Department of Geriatric Medicine, Kobe University School of Medicine, Japan.
A corpus of evidence suggests that T-helper type 1 (Th1)-dependent cellular
immunity plays a pivotal role in the pathogenesis of autoimmune diabetes.
This study was intended to find ways to prevent the development of NOD
diabetes using a neutralizing anti-interleukin (IL)-12 antibody (C17.8)
that inhibits Thl cell differentiation. When C17.8 was administered from 5
to 30 weeks of age, NOD mice exhibited suppression of both insulitis and
diabetes. However, when C17.8 administration ceased at 15 weeks of age, 8
of 13 recipients showed diabetes at 30 weeks of age. These results suggest
that IL-12 plays an important role not only in the development of effector
cells but also in their activation. In contrast, when C17.8 was injected
into 2-week-old female NOD mice for 6 consecutive days, all 16 recipients
showed diabetes at 30 weeks of age, whereas 12 of 20 control mice became
diabetic. This result suggests that depletion of endogenous IL-12 at a
young age results in the enhancement of diabetes. Flow cytometric analysis
indicated that activated memory T-cells were present in higher numbers
after C17.8 treatment. Transfer of spleen cells from 15-week-old
C17.8-treated NOD mice to NOD-scid mice resulted in an earlier onset and a
higher incidence of diabetes. Furthermore, administration of C17.8 to
2-week-old NOD mice also resulted in a much earlier onset of diabetes.
These results suggest that short-term treatment with anti-IL-12 antibody
prohibits IL-2 production at a young age, which may influence the expansion
and apoptosis of pathogenic T-cells, resulting in the acceleration of
autoimmune diabetes.