[Investigations on the mechanism(s) of the production of anti-thyroid hormone antibodies 3:Production of anti-rabbit thyroglobulin and anti-thyroid hormone antibodies in rabbits immunized with rabbit thyroglobulin].

Recently, the presence of anti-thyroid hormone antibodies has been reported in many cases of thyroidal and non-thyroidal disorders. In order to elucidate the immunological mechanism(s) in the production of anti-thyroid hormone antibodies, we immunized outbred rabbits and mice with different H-2 and Igh allotypes with human thyroglobulin (HTg) and showed that the production of both anti-HTg and anti-thyroid hormone antibodies is genetically controlled. In our present study, rabbit thyroglobulin (RTg) was purified from 4 rabbit thyroid glands and was immunized in two rabbits (RG-I, RG-2). The two rabbits were then serially bled and tested for the presence of anti-RTg and anti-thyroid hormone antibodies. In both rabbits, the production of anti-RTg and anti-thyroid hormone antibodies was observed. The binding constant of anti-RTg, anti-T4 and anti-T3 antibodies in RG-1 were 6 X 10(9)M-1, 9.5 X 10(8)M-1, 4.6 X 10(8)M-1, and those in RG-2 were 6.5 X 10(9)M-1, 5.6 X 10(8)M-1, 1.6 X 10(8)M-1, respectively. These results further strengthen the possibility that the antigen of the anti-thyroid hormone antibodies observed in various disorders so far reported is the HTg molecule. In addition, the fact that anti-RTg antibodies had a higher binding constant and capacity than anti-thyroid hormone antibodies suggests that the antigenic site(s) of RTg, which contains thyroid hormones, is not highly immunogenic.