Specific stimulation of MHC-transgenic mouse T-cell hybridomas with xenogeneic APC.

From the recombinant human leukocyte antigen (HLA)-DR1/H2-E(k) major histocompatibility complex (MHC) class II-transgenic mice, we have generated two CD4(+) T-cell hybridomas specific for peptides which were derived from human prostatic acid phosphatase (PAP) complexed to the human class II molecule HLA-DR1. Both hybridomas strongly react to PAP-pulsed antigen-presenting cells (APC) from transgenic mice. Interestingly, these hybridomas also responded to PAP antigen presented by HLA-DR1-positive human APC. The species-mismatched T-cell stimulation occurs despite the biologic discordance in participating accessory molecules, which are required for the optimal T-cell-APC interaction. Our results demonstrate various degrees of functional interaction between coreceptors, costimulatory molecules, and integrins, which are expressed on the surface of T-cell hybridomas and heterologous APC.