Thyroid cells in Graves' disease and Hashimoto's thyroiditis stimulate allogeneic T cells when pretreated with phorbol ester.
OBJECTIVE
To assess the capacity of thyroid follicular cells to function as antigen presenting cells, we have examined their ability to stimulate allogeneic T cells.


METHODS
Thyroid follicular cells were pretreated with interferon-gamma or phorbol myristate acetate, washed thoroughly, and their capacity to induce allogeneic T cell proliferation was determined.


METHODS
Thyroid cells were prepared using thyroidectomy specimens from eight patients with Graves' disease, one with Hashimoto's thyroiditis and two with non-toxic multinodular goitre.


METHODS
T cell 3H-thymidine incorporation was measured after a 16-hour incubation period with the isotope, 3 days after co-culture of T cells and thyroid cells.


RESULTS
Four of the eight thyroid cell preparations from thyroid autoimmunity patients failed to stimulate T cells, although there was a significant, weak stimulation for the whole group (P < 0.05): interferon-gamma pretreatment had no effect on this. Phorbol myristate acetate pretreatment significantly increased the ability of thyroid cells (from both autoimmune and multinodular glands) to stimulate T cells (P < 0.05); this was time and concentration dependent. Cell fixation after PMA treatment did not abolish this stimulatory activity, which could be transferred by supernatants from unfixed cells; exogenous interleukin-1 did not mimic the activity.


CONCLUSIONS
Thyroid cells expressing major histocompatibility complex class II molecules only weakly and inconsistently stimulate allogeneic T cells, compared to thyroid cells pretreated with phorbol myristate acetate, a difference which may be due to the expression of an unidentified co-stimulatory signal induced by phorbol ester.
Tandon
N
N
Department of Medicine, University of Sheffield, UK.
Weetman
A P
AP
D000938:Antigen-Presenting Cells / Q000276:immunology*; D006111:Graves Disease / Q000276:immunology* / Q000473:pathology; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013961:Thyroid Gland / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D013967:Thyroiditis, Autoimmune / Q000276:immunology* / Q000473:pathology
D006684:HLA-DR Antigens; D013755:Tetradecanoylphorbol Acetate