Specificity of antigen processing for MHC class I restricted presentation is conserved between mouse and man.

Alloreactive mouse cytotoxic T lymphocytes (CTL) specific for particular peptides presented by H-2Kb molecules on mouse cells were found to recognize human cells transfected with Kb. The CTL-recognized peptides (probably derived from conserved proteins) were extracted from Kb-expressing human or mouse cells, respectively, and compared biochemically by high resolution high performance liquid chromatography. The results strongly suggest identity of peptides processed by cells from both species and thus indicate that the specificity of the processing machinery used in the major histocompatibility complex (MHC) class I-restricted pathway, probably including enzymes, transport mechanisms, and chaperons, is highly conserved across species. The results are consistent with the notion that MHC molecules themselves have an instructive role in processing.