Baboons are less LPS-sensitive than humans, even though their immune response mechanisms are similar. Since TNF alpha is a central mediator of the LPS-response we cloned and sequenced the baboon TNF alpha cDNA and compared the resulting sequence with the human TNF alpha sequence. Analysis of the TNF alpha protein coding region indicated 97% homology and of the 3' UTF 89%. The predicted baboon TNF alpha amino acid sequence differed at 10 positions from the human sequence. "TA" rich motifs within the 3' UTR were 100% homologous. (C) 1997 Elsevier Science Ltd. All rights reserved.