The authors regret that information was omitted in a paragraph in the Discussion section (p. 144). The corrected paragraph follows.
We have been unable to assess functionally the MHC class I specificity of pygmy chimpanzee KIR because of the small quantities of pygmy chimpanzee blood available. However, some inferences as to the possible receptor specificities can be made from structural comparison with human and common chimpanzee KIR. Based on their phylogenetic conservation, Pp-KIR2DL4 is a candidate MHC-G receptor and Pp-KIR3DL4 a candidate receptor for the C2 MHC-C specificity. By analogy with their paralogs in the other species, Pp-KIR3DLa, Pp-KIR3DLb, Pp-KIR3DLc, and Pp-KIR3DSa are candidates for MHC-A and -B receptors. In the D1 domain, Pp-KIR3DLa is distinguished from the other Pp-KIR3DL by several residues (E21, K44, D48, T49, E54, and H55) which it shares with human KIR2DL2, KIR2DL3, KIR2DS2, and KIR2DS4. In the crystallographic structure of the complex of KIR2DL2 with HLA-Cw3, these residues contribute to the interaction surface (46), raising the possibility that Pp-KIR3DLa may have affinity for MHC-C allotypes with the C1 motif. No Papa-C alleles encoding the C1 motif have been found in the pygmy chimpanzees studied here (36), but the small number of animals does not mean that such allotypes are not present in the population at large.
