Experimental arthritis in thymectomized Rats with an impaired humoral immune response

ADJUVANT-induced arthritis in Rats shares many of the clinical and pathological features of human rheumatoid arthritis¹. Cell-mediated immune mechanisms are believed to be of importance in the experimentally induced arthritis². Although this experimental disease can be transferred by thoracic duct lymphocytes from sensitized to non-sensitized syngeneic recipient Rats³, it has been reported that neonatal thymectomy does not prevent subsequent induction of adjuvant arthritis⁴. We recently observed induction of adjuvant arthritis in Rats subjected to neonatal thymectomy, but not in sham thymectomized Rats. The accompanying finding that the severity of the arthritis was related to depression of an apparently thymus dependent antibody response may be a clue to the immunopathological mechanism involved in this arthritis model.