cDNA cloning of human Allograft Inflammatory Factor-1: Tissue distribution, cytokine induction, and mRNA expression in injured rat carotid arteries

We have previously identified a partial cDNA fragment obtained from rat carotid arteries subject to balloon angioplasty which is increased in response to vascular injury. We now report the isolation and characterization of a full length human clone which is 98% homologous at the amino acid level to the rat Allograft Inflammatory Factor-1 (AIF-1), a gene previously reported to be expressed in rat IFNγ-activated macrophages. This transcript is expressed in low levels in undamaged, and increases 1 day and 3 days, and declines 7 days post balloon angioplasty. This human AIF-1 homologue is inducible in serum and cytokine-stimulated human smooth muscle cells. Interestingly, human tissue distribution indicates a constitutive expression in lymphoid tissue which can be augmented by mitogens. In summary, human AIF represents a cytokine inducible, tissue-specific, and highly conserved transcript transiently expressed in response to vascular trauma.