Neutrophil elicitation into tissue is an essential
element of the host defense in response to various stimuli, including, tissue injury,
infection, or
cancer. This event has gained renewed interest with the discovery of a family of small
polypeptides (less than 10 kD). The salient features of these
cytokines are the presence of four
cysteine amino acids (first two separated by one
amino acid; C-X-C) and their ability to induce neutrophil chemotaxis and activation. Recently, our laboratories have discovered a new member of this C-X-C
chemotactic cytokine supergene family, neutrophil-activating
peptide, ENA-78. ENA-78 shares significant amino acid sequence homology with
neutrophil activating peptide-2 (NAP-2; 53%), growth regulated oncogene/
melanoma growth stimulatory activity (GRO alpha; 52%), and
IL-8 (22%). In addition, ENA-78 appears to activate neutrophils through the
IL-8 receptor. Since both in vitro and in vivo
biological fluids may contain an array of
chemotactic cytokines that may be relevant to the activation and chemotaxis of neutrophils, we have developed a highly specific and sensitive sandwich ELISA for the detection of ENA-78.