Helper and Suppressor Activities of Lymphocyte Subsets on Antithyroglobulin Production in Vitro*

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Abstract
The regulatory activities of T cells on specific antithyroglobulin (anti-Tg) and nonspecific Ig secretion in cultures of peripheral blood lymphocytes (PBL) of 5 patients with autoimmune thyroid diseases and high levels of serum anti-Tg were studied. PBL were separated into a non-T population, including B-cells and monocytes and a T-cell population by rosetting with sheep red cells. T-Cells were further separated into T helper (Th) and T suppressor (Ts) subsets by a panning technique using the monoclonal antibodies anti-Leu 3a and anti-Leu 2a, respectively. The 3 sets of cells, i.e. B, Th and Ts, from patients and from normal individuals were cocultured in various combinations and stimulated with the polyclonal stimulant pokeweed mitogen. A sensitive plaque assay was used to enumerate cells producing anti-Tg and protein A-binding immunoglobulins. The PBL of both patients and normal individuals had Tg-specific suppressor cells. Ts-cells from patients in syngeneic or allogeneic combinations with B- and Th-cells at a ratio of 1:1:1 suppressed the pokeweed mitogen-induced anti-Tg response to 41 .+-. 8% (.+-. SE) and 50 .+-. 20% of the control value, respectively, while Ts from normal individuals suppressed the response to 7 .+-. 3% of the control value. The suppressive effect of the Ts-cells from patients and normal individuals on nonspecific Ig secretion was similar (reduced to 10-15% of control). There appeared to be a deficiency in Tg-specific suppressor activity in PBL of patients. Th-cells from patients (syngeneic or allogeneic) cocultured with patient B-cells produced a greater anti-Tg response than Th-cells from normal individuals. The helper activities of Th-cells of patients and normal individuals on nonspecific Ig secretion were similar. There appeared to be an increase in Tg-specific helper activity in PBL of patients.