Figure 5.

Reduction of the hCD4⁺ T-cell response to dominant-negative mutant class II transactivator (CIITA-DN) porcine aortic endothelial cells (pAECs). Aortic endothelial cells from CIITA-DN and wild-type (WT; sibling of CIITA-DN) pigs were either non-activated (quiescent) or activated with porcine interferon-γ (IFN-γ; 50 ng/ml) for 48 hr. (a) Human (h) CD4⁺ T cells were co-cultured with pAECs for 7 days (n = 6). The response of hCD4⁺ T cells was evaluated by [³H]thymidine incorporation. As a negative control, hCD4⁺ T cells were cultured with culture medium (spont). There was a significantly lower hCD4⁺ T-cell response to CIITA-DN pAECs compared with WT pAECs (**P < 0·01). (b) The hCD4⁺ T-cell responses to both CIITA-DN and WT pAECs were evaluated over a period of 9 days in mixed lymphocyte reaction (2–9 days co-culture). Results are representative of three independent experiments. The hCD4⁺ T-cell response to CIITA-DN pAECs remained minimal throughout the 9 days of culture.