Human and murine interleukin 1 possess sequence and structural similarities.

The molecular cloning and sequence analysis for human and murine interleukin 1 precursor have recently been described. Comparison of the amino acid sequences resulting from these data can be used to aid in the identification of conserved regions essential to biological activity. We report results which confirm the relationship between these two molecules and suggest that specific regions may be essential for activity. Amino terminal sequence analysis of a 19,000 Mr biologically active IL-1 isolated from stimulated human monocytes reveals a sequence which is in good agreement with that inferred from the human cDNA and, furthermore, locates the processed amino terminus at a site similar to that described for the murine sequence.