PRESERVATION OF FUNCTIONING HUMAN THYROID ORGANOIDS IN THE SCID MOUSE.4. IN-VIVO SELECTION OF INTRATHYROIDAL T-CELL RECEPTOR REPERTOIRE

To study the in vivo influence of thyroid cells on the T cell receptor repertoire in human autoimmune thyroid disease, we mixed lymphocyte-f ree thyrocytes (similar to 1.2 x 10(6)) from patients with Graves' dis ease with autologous peripheral blood mononuclear cells (PBMC; similar to 1.5 x 10(6)) and transplanted this mixture sc into scid mice while suspended in a basement membrane gel(similar to 0.4 mi). Controls inc luded mice that received either thyrocytes only or PBMC only. The resu lting artificial mixed cell thyroid organoids were explanted after 5 w eeks, and their T cell receptor repertoire was examined. Of a total of 63 organoids constructed, 60 were recovered (95.2%). Total RNA was ex tracted and then analyzed by reverse transcription-PCR primarily for h uman T cell receptor (hTcR) V beta gene expression using 21 hTcR V bet a amplimers. A restricted pattern of hTcR V beta gene expression was f ound, with 6 V beta genes (V beta 5, 6, 7, 8, 13.1, and 18) predominan tly expressed [P < 0.05, by ANOVA on ranks and Student-Newman-Keul's ( SNK) test]. PBMC and control organoids showed no preferential selectio n of particular hTcR V gene-expressing T cells. This reductionist, mix ed cell, thyroid model reflected earlier observations in human and mur ine autoimmune thyroid diseases in which a bias in hTcR V gene family expression had been observed. The model permitted in vivo T cell selec tion and/or enrichment of potentially disease relevant human T cells.