The relative contributions of immune system and target organ to variation in susceptibility of rats to experimental allergic thyroiditis

Abstract

Previous investigations of the cellular basis of genetic susceptibility to experimental allergic thyroiditis (EAT) in semi-allogeneic mice bearing thyroid grafts from resistant, parental strain donors have indicated that these grafts remain relatively resistant to EAT when this is induced in the susceptible bearer. It was concluded that genetic control of susceptibility to EAT is expressed in both the immune system and the thyroid gland. Our experiments in which thyroid grafts were transferred to fully allogeneic, but immunologically tolerant, recipient rats indicate that thyroid tissue from an EAT-resistant strain of rat becomes entirely susceptible when transplanted into a susceptible host. The differing susceptibility of thyroid grafts in semi-allogeneic and tolerant allogeneic hosts may result from restrictions on interaction between host lymphocytes and the graft in the former situation. The present findings call into serious doubt the proposition that genetically determined resistance to EAT is mediated, to any extent, at the level of the target organ.

Potential Association of Cutibacterium acnes with Sarcoidosis as an Endogenous Hypersensitivity Infection

“…In this animal model, DA strain rats are high responders and PVG strain rats are low responders; serum antibody titers to thyroglobulin are elevated in both DA and PVG rats, but lymphocytic thyroiditis occurs only in DA rats [ 59 ]. Such disease susceptibility of the host’s immune system [ 60 ] and dissociation of humoral and cellular immune responses to an identical antigen are also observed in sarcoidosis patients if C. acnes is assumed to be an intracellular antigen like the organ-specific autoantigen. Furthermore, experimental autoimmune thyroiditis is always self-limiting when induced in healthy animals, and DA rats that have undergone spontaneous remission are resistant to re-induction of experimental autoimmune thyroiditis [ 61 ].…”