Concanavalin A induces microtubule assembly and specific granule discharge in human polymorphonuclear leukocytes.

Human neutrophils stimulated by concanavalin A (Con A, 100 microng/ml) contained markedly enhanced numbers of microtubules and discharged peroxidase-negative (specific) but not peroxidase-position (azurophile) granules. Release of lysozyme from specific granules was dose and time dependent, could be inhibitied by alpha-methyl-D-mannoside, and enhanced by cytochalasin B. Many microtubules were associated with internalized plasma membrane bearing Con A binding sites.