Transcription of a Broad Range of Self-Antigens in Human Thymus Suggests a Role for Central Mechanisms in Tolerance Toward Peripheral Antigens

摘要: The role of the thymus in induction tolerance to peripheral antigens is not yet well defined. One impending question involves how can acquire diversity nonthymic self-Ags for process negative selection. To investigate whether Ags are synthesized itself, we have determined expression a panel circulating and cell-bound Ags, some which targets autoimmune diseases, at mRNA level total thymic tissue its main cellular fractions. Normalized calibrated RT-PCR experiments demonstrated presence transcripts human thymi from 8 days 13-yr-old donors. Out 12 glands, albumin were found 12; insulin, glucagon, thyroid peroxidase, glutamic acid decarboxylase (GAD)-67 six, thyroglobulin five, myelin basic protein retinal S Ag three, GAD-65 one. levels detected age-related but also showed marked interindividual differences. Cytokeratin-positive stromal epithelial cells, likely source these, contained up 200 transcript copies most expressed per cell. These results implicate wide representation support view that involved establishment Ags. existence such central mechanism crucial understanding organ-specific diseases.