Generation and characterization of CD2-dnTGFBRII transgenic mice. (A) Schematic representation (not to scale) of CD2-dnTGFBRII construct. The open box represents extracellular and transmembrane portions of human TGF-β receptor type II between nucleotides -7 and +573 followed by a stop codon. Primers used for PCR analysis of the transgene insertion in transgene-positive mice are also shown. (B) RT-PCR performed using primers indicated in panel A for the Tg-TGFR-specific transcript or with primers specific for β-actin as control on cDNA isolated from total splenocytes (lane 1), purified B cells (lane 2 and 1/10 lane 3), purified CD4⁺ T cells (lane 4 and 1/10 lane 5), and purified CD8⁺ T cells (lane 6 and 1/10 lane 7). (C-E) Purified CD4⁺ (C) or CD8⁺ (D) from 6-week-old Tg⁺ and control mice were stimulated with anti-CD3 mAb (5 μg/mL) and anti-CD28 (10 μg/mL) precoated on plastic wells in 96-well plates for 72 hours in the presence or absence of 3 ng/mL TGF-β1. B220⁺ cells (E) were stimulated with 10 μg/mL LPS for 48 hours. One microcurie (0.037 MBq) per well of [³H]thymidine was added for the last 8 hours of culture. ^** indicates statistically significant decrease (P < .01; n = 4) in [³H]thymidine incorporation between control and Tg⁺ mice; ^***, statistically significant decrease (P < .01; n = 4) in [³H]thymidine incorporation in the presence of exogenously added TGF-β1. Numbers above bars indicate mean values. Error bars show SEM.