Neutrophil chemotactic N-acetyl peptides from the calpain small subunit are also chemotactic for immunocytes.

N-terminal peptides from the calpain small subunit were shown to have dose-dependent chemotactic activity toward several types of leukemia cells: T cell, B cell, monocyte and granulocyte/monocyte line leukemia cells. In order to prove that chemotaxis is mediated via receptors, a fluorescein-labeled probe was prepared from one of the N-terminal peptides and its interaction with peripheral leukocytes was estimated by means of flow cytometry, resulting in staining not only of neutrophils but also of most of the monocytes and more than half of the T and B lymphocytes. The results indicate that calpain-derived N-terminal peptides may be involved in defense mechanisms, inducing chemotaxis of immunocytes as well as that of neutrophils.