Fig. 1

Schematic drawing showing locations of CTL epitopes within the NP open reading frame (A) and the concept of BM chimeric mice (B)

Amino acid sequences are expressed in single-letter code. BM-derived APCs are expected to express only the haplotype of their BM donor and thus present peptides in the context of the BM donor MHC allele rather than both alleles, whereas the myocytes (and other somatic cells) in the chimeras are expected to express both MHC alleles; thus, if they prime CTL responses in vivo, they would present peptides restricted by both haplotypes. Since the thymic epithelial cells express both parental MHC alleles, the T cell receptor repertoires are expected to include receptors that recognize peptides in the context of both parental haplotypes, even though the T cells themselves only express the BM donor’s haplotype.