Unique CD4⁺ T cells in TCR α chain-deficient class I MHC-restricted TCR transgenic mice: Role in a superantigen-mediated disease process

Mice carrying a transgenic TCR with targeted disruption of the TCR α chain (H-Y α(-/-)) possess CD4⁺ T cells which express the transgenic TCR β without the α chain. These mice developed the murine acquired immunodeficiency syndrome (MAIDS) after infection with LP-BM5 retroviruses, a process which requires CD4⁺ T cells. These cells are negative for TCR δ chain and pre-TCR α chain expression, and thus express a unique surface receptor with the TCR β chain as a component. The cells respond to MAIDS virus-associated superantigen and concanavalin A, but not to protein antigens such as ovalbumin. Thus, this novel surface receptor appears to play an important role in the pathogenesis of MAIDS.