T cell competition for the antigen-presenting cell as a model for immunodominance in the cytotoxic T lymphocyte response against minor histocompatibility antigens

We recently demonstrated that spleen cells primed against dominant BALB.B a ntigens can inhibit the cytotoxic T lymphocyte (CTL) response against subdo minant antigens in vitro. In this study, we show that this interference is dependent on CD8(+), but not CD4(+), T cells directed against dominant anti gens. Similar to immunodominance in vivo, T cell interference in vitro requ ired presentation of dominant and sobdominant antigens by the same antigen- presenting cell. In vivo priming with cells expressing dominant and subdomi nant antigens did not induce long-lasting unresponsiveness against the latt er. These results support a model in which immunodominance is mediated by T cell competition. In line with this, we found that the immunodominance eff ects in the CTL response against these minor histocompatibility antigens co uld be broken by immunization with live bone marrow-derived dendritic cells .