Diabetes, Vol 40, Issue 12 1586-1597, Copyright © 1991 by American Diabetes Association
Direct involvement of macrophages in destruction of beta-cells leading to development of diabetes in virus-infected mice
HS Baek and JW Yoon
Laboratory of Viral and Immunopathogenesis of Diabetes, Julia McFarlane Diabetes Research Centre, University of Calgary, Alberta, Canada.
A single administration of complete Freund's adjuvant (CFA), type 1
carrageenan (Car), or silica 7, 2, and 2 days, respectively, before
infection with a low dose (1 x 10(2) plaque-forming units/mouse) of
encephalomyocarditis D (EMC-D) virus resulted in a significant increase in
the incidence of diabetes in SJL/J mice (100%) compared with untreated
EMC-D virus-infected mice (40%). Peritoneal macrophages were isolated from
uninfected SJL/J mice, which had been treated once with silica, and
transferred into SJL/J mice 2 days before low-dose EMC-D infection.
Approximately 90% of the mice became diabetic, whereas 30% of mice that
received virus alone became diabetic. The depletion of macrophages by
treatment with the combined anti-Mac-1 and anti-Mac-2 monoclonal antibodies
after a single administration of CFA, Car, or silica resulted in almost
complete prevention of beta-cell destruction in EMC-D virus-infected mice.
Furthermore, none of the mice in which macrophages were depleted by
long-term treatment with silica and 10% of the mice treated with Car before
virus infection became diabetic. On the basis of these observations, we
conclude that macrophages are directly involved in the destruction of
beta-cells, leading to the development of clinical diabetes in EMC-D
virus-infected mice.