The primary structures of human, bovine, and murine granulocyte chemotactic protein 2 (GCP-2) (61-67% homology) were disclosed by amino acid sequence analysis of purified natural protein. GCP-2 chemo-attracts neutrophilic granulocytes and induces enzyme release and an increase in [Ca~*]j in these cells in vitro and has proinflammatory properties in vivo. Human, bovine, and murine GCP-2 occur as different N-terminally truncated forms. In contrast to human GCP-2. for murine GCP-2 C-terminally extended forms (e.g. LIX) have also been isolated. For human and bovine GCP-2. no difference in potency is observed between these isoforms, whereas for murine GCP-2, N-terminal as well as C-terminal truncation result in increased specific activity. Similar to IL-8. but in contrast to the other ELRTCXC chemokines. human GCP-2 can efficiently activate cells by binding to CXCR1 and CXCR2. For human and murine GCP-2. the cDNA has been cloned.