Human P-defensins are antimicrobial peptides that may be critical in the in
nate immune response to infection. hBD1 and hBD2 are expressed in oral epit
helial cells and are detected near the surface of oral tissue, consistent w
ith a role in the epithelial protective barrier function. In this report, w
e examine secretion of P-defensins in vitro and in biological fluid using P
roteinChip((R)) Array, surface enhanced laser desorption/ionization (SELDI)
technology combined with time-of-flight mass spectrometry. We show that th
e 47-amino acid form of hBD1 and the 41-amino acid form of hBD2 are the maj
or secreted forms. These forms are both expressed and secreted under condit
ions anticipated from previous analysis of P-defensin mRNAs; specifically,
hBD1 is detected in culture supernatant from both unstimulated and stimulat
ed cells, and hBD2 is detected only in stimulated cells. Identity of hBD1 a
nd hBD2 was confirmed by immunocapture on the ProteinChip surface. Both pep
tides are also present in gingival crevicular fluid that accumulates betwee
n the tissue and tooth surface, although hBD1 is also found in several smal
ler forms suggesting extracellular proteolysis. This methodology offers sev
eral technical advantages for detection of defensins in biological fluids,
including ease and speed of screening, no need for HPLC preliminary process
ing, and small sample size. (C) 2001 Elsevier Science B.V. All rights reser
ved.