Expression of nonspecific esterase (NSE) by thyroid follicular epithelium as a marker for the target organ susceptibility to immune system attack

Spontaneous autoimmune thyroiditis in obese strain (OS) chickens provides a n excellent animal model for the study of Hashimoto's autoimmune thyroiditi s in humans, The data presented in this paper indicate that nonspecific est erases (NSE) may play a role in or serve as a marker for the target organ s usceptibility. Experiments have shown that follicular epithelial cells and interfollicular macrophages in connective tissue stain positively for NSE a s early as the first day after hatching, a time at which infiltrating lymph ocytes are not yet observed. We also have observed NSE positivity of follic ular cells in the vicinity of mononuclear cell infiltration in all OS chick ens, as well as weaker positivity in 6-month-old, avian leukosis virus free , Brown Leghorn outbred chickens, which appears in each case to correlate w ith infiltration of lymphocytes. In F-2 hybrids between OS and healthy CB i nbred chickens, the intensity of NSE staining was more variable than in OS chickens. Using specific inhibitors eserine, Na-taurocholat and p-hydroxyme rcuribenzoic acid, we were able to inhibit in vitro the NSE positivity of t hyroid gland follicular epithelium, indicating that this staining was not a n artifact. Experiments are currently in progress to clarify the relationsh ip between the presence of NSE in follicular epithelium and the predisposit ion to spontaneous autoimmune thyroiditis.