CHARACTERIZATION OF INLERLEUKIN-8 RECEPTORS IN NONHUMAN-PRIMATES

Interleukin-8 is a chemokine with a potent neutrophil chemoatractant a ctivity. In humans, two different cDNAs encoding human IL8 receptors d esignated IL8RA and IL8RB have been cloned. IL8RA binds IL8, while IL8 RB binds IL8 as well as other alpha-chemokines. Both human IL8Rs are e ncoded by two genes physically linked on chromosome 2. The IL8RA and I L8RB genes have open reading frames (ORF) lacking introns. By direct s equencing of the polymerase chain reaction products, we sequenced the IL8R genes of cell lines from four non-human primates: chimpanzee, gor illa, orangutan, and macaca. The IL8RB encodes an ORF in the four non- human primates, showing 95%-99% similarity to the human IL8RB sequence . The IL8RA homologue in gorilla and chimpanzee consisted of two ORF 9 8%-99% identical to the human sequence. The macaca and orangutan IL8RA homologues are pseudogenes: a 2 base pair insertion generated a seque nce with several stop codons. In addition, we describe the physical li nkage of these genes in the four non-human primates and discuss the ev olutionary implications of these findings.