Autoimmunity
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Comparative Study
Induction of microsomal antigen and comparison with histologic localization of HLA-DR in Graves' thyroid tissue.
We have characterized thyroid microsomal antigen (M-Ag) prepared from Graves' and normal thyroid tissues using 100,000 x g thyroid membrane fractions in enzyme-linked immunosorbent assays with pooled polyclonal human sera containing high titers of antibody to M-Ag. A ten-fold parallel increase in dose inhibition potencies occurred with M-Ag preparations from Graves' as compared to normal thyroid tissue. The M-Ag preparations were further evaluated by SDS-polyacrylamide gel electrophoresis and proteins visualized by Western blot using high titer microsomal antibody (M-Ab) sera (n = 2) devoid of thyroglobulin antibody activity. ⋯ This was in contrast to follicular cell staining for HLA-DR antigen which was present in 6 of 10 Graves' tissues examined and absent in normal thyroid tissue. Staining for HLA-DR antigen also occurred on the follicular cell surface membrane with occasional enhancement at the thyrocyte apical cell membrane. We conclude: a) M-Ag is induced approximately 10-fold in Graves' thyroid tissue and can be objectively quantified in ELISA systems, 2) There were no detectable qualitative differences between M-Ag from Graves' and normal thyroid tissue, and 3) HLA-DR antigen was detected on 60% Graves' tissues in a cell surface distribution similar to that observed for M-Ag in both Graves' and normal tissues.