POLYAMINES FOUND IN GINGIVAL FLUID INHIBIT CHEMOTAXIS BY HUMAN POLYMORPHONUCLEAR LEUKOCYTES IN-VITRO

PUTRESCINE AND SPERMIDINE OCCUR AT CONCENTRATIONS approaching 1 mM in gingival fluid at diseased periodontal sites. Previous work demonstrat es that these polyamines potentiate Ca2+ signaling in polymorphonuclea r leukocytes (PMNs), resulting in enhanced degranulation and superoxid e generation. The present study extends this work by characterizing th e effects of polyamines on PMN chemotaxis and phagocytosis, in which C a2+ signaling plays a less defined regulatory role. Putrescine (1 mM) and spermidine (0.1 to 0.5 mM) significantly inhibited chemotaxis to f Met-Leu-Phe and C5a (P < 0.05). This inhibition was not strongly relat ed to any effect polyamines have on PMN adhesion, actin polymerization , or formyl peptide receptor expression. Neither putrescine nor spermi dine had a significant impact on phagocytosis of opsonized bacteria by PMNs. Thus, at concentrations similar to those found in gingival flui d, polyamines could potentially inhibit recruitment of PMNs to disease d pockets without impairing their ability to engulf invading bacteria.