ONTOGENIC DEVELOPMENT OF CYTOTOXIC AND SUPPRESSOR CELLS IN OBESE STRAIN (OS) CHICKENS WITH SPONTANEOUS THYROIDITIS

Publisher Summary This chapter examines the ontogenic development of cytotoxic and suppressor cells in obese strain (OS) chickens with spontaneous thyroiditis. OS chickens spontaneously develop an autoimmune thyroiditis closely resembling that of human Hashimoto disease and characterized by a mononuclear infiltration of the thyroid gland beginning soon after hatching. Concomittant with this is the appearance of circulating autoantibodies to thyroglobulin (TgAAb) and thyroid microsomal antigens. While the importance of the humoral immune response as an effector mechanism in the Os has been well documented, the distinction between complement and K cells as mediators of antibody dependent destruction of the thyroid has not been determined. The role of thyroid-specific cytotoxic T cells has also not yet been evaluated. This chapter discusses a study of OS chicken to investigate the levels of antibody-dependent cellular cytotoxicity, the existence of Tg-specific direct cellular cytotoxicity, and also any abnormalities in the immune suppression mechanisms that may allow escape of autoreactive cells. In the initial studies, blood leucocytes from a total of 155 Os and 90 normal chickens of varying age, genotype, and—for the OS—extent of disease were screened for the three forms of cytotoxicities.