Mutational analysis of chicken interleukin 2

Chicken interleukin 2 (chlL-2) has low, but significant, homology to both m ammalian IL-2 and mammalian IL-15, In vie,v of its unique phylogenetic posi tion and potential use as a vaccine adjuvant, a detailed mutational analysi s for critical functional sites was undertaken. It was found that Asp17 is a critical N terminal contact site for binding to the putative chIL-2 recep tor, which is similar to results obtained for mammalian IL-2 and IL-15, Ana lysis of the C terminus did not reveal a single critical amino acid. Howeve r, deletion mutant studies demonstrated that removal of C terminal amino ac ids yielded proteins with decreased bioactivity and that this decrease was a function of the number and kind of amino acids removed. This study is the first nonmammalian IL-2 mutational analysis and proposes a model for the i nteraction between chIL-2 and its receptor. (C) 2001 Academic Press.