reflect a role for ica69 as an autoantigen or a role for ica69 protein function to begin an analysis of these two alternatives we measured t cell autoreactivity to ica69 and its immunodominant t cell epitope tep69 in 10 week old nod females proliferative in vitro recall responses were assessed in draining lymph nodes from various tissues in order to localize where t cell tolerance to ica69 was lost proliferative t cell responses to ica69 and tep69 were detected in both pancreatic and submandibular lymph node cells fig2 a b but not in popliteal or axillary lymph nodes fig2 c d equally exclusive to pancreatic and submandibular lymph node cells we observed t cell proliferative responses to bovine serum albumin bsa and its immunodominant epitope abbos a peptide that displays amino acid homology and antigenic mimicry with tep69 14 spleen cell responses to ica69 tep69 bsa and abbos were present as previously described by us 21 and others 24 data not shown but for example see fig3 f the localization of spontaneous ica69 immune responsiveness to the submandibular lymph nodes specifically links ica69 autoimmunity with the salivary glands and suggests that ica69 is a candidate autoantigen in nod mouse pss to test this conclusion and determine the role for ica69 autoimmunity in the progression of nod mouse pss we employed an immunotherapy strategy 14 treatment of nod mice with the abbos mimicry peptide induces long lasting t cell tolerance to tep69 in most animals.