MOLECULAR-CLONING AND SEQUENCE-ANALYSIS OF INTERLEUKIN-16 FROM NONHUMAN-PRIMATES AND FROM THE MOUSE

Interleukin 16 (IL-16) is synthesized as a 67000 M-r precursor (pro-IL -16), but only a carboxy terminal part of 12000-14000 M-r is secreted by CD8(+) lymphocytes. This lymphokine binds to CD4 and has been shown to induce migration, affect the activation state of T cells, and inhi bit immunodeficiency virus replication. It has been suggested that CD8 (+) cell-derived soluble factors play a pivotal role in protecting nat ural-host nonhuman primates from developing immunodeficiency following SIV infection. In a first attempt to address this question, we cloned and sequenced the IL-16 cDNA from different primates. Here we report the pro-IL-16 sequence from chimpanzees, African green monkeys (AGM), rhesus macaques, and cynomolgus macaques. In order to compare and anal yze structural motifs possibly involved in processing, intracellular t argeting, or secretion, we extended our study to the New World monkeys saimiri and aotus and to the mouse. Alignments of deduced amino acids reveal that the human protein shares 99% similarity to that of chimpa nzees, approximately 95% to rhesus, cynomolgus and ACM, about 90% to a otus and saimiri, and 77.5% to the mouse. Phylogenetic analyses reveal ed the expected evolutionary groupings.