N. Tandon et al., EXPRESSION OF THE COSTIMULATORY MOLECULE B7 BB1 IN AUTOIMMUNE THYROID-DISEASE/, Quarterly Journal of Medicine, 87(4), 1994, pp. 231-236
Efficient antigen presentation requires the provision of a costimulato
ry signal, the best characterized of which is B7/BB1. It is unclear wh
ether thyroid cells expressing class II molecules can present autoanti
gens to T cells, although this has been suggested as an important mech
anism in the initiation of Graves' disease and Hashimoto's thyroiditis
. We have found that thyroid cells from patients with thyroid autoimmu
nity do not express B7/BB1 in vivo or in vitro, even after activation
with the cytokines interleukin-1 or gamma-interferon, or with a phorbo
l ester. Increased numbers of CD20(+) B cells and CD14(+) dendritic ce
lls expressing B7/BB1 were found in intrathyroidal lymphocyte preparat
ions from such patients compared to peripheral blood. These results su
ggest that conventional antigen-presenting cells rather than thyroid c
ells provide B7/BB1 costimulatory activity in autoimmune thyroid disea
se, and argue against a role for the thyroid cells themselves in autoa
ntigen presentation to T cells via the B7/BB1 pathway.