Defensins and LL-37: a review of function in the gingival epithelium

Abstract

Antimicrobial peptides represent an important aspect of the innate defense system that contributes to the control of bacterial colonization and infection. As studies have progressed it has become clear that antimicrobial peptides manifest other functions in addition to their antimicrobial effects. These functions include chemotaxis of numerous types of host cells involved in both the innate and adaptive immune responses. In this review, the antimicrobial activity, the regulation and the contribution to host homeostasis of alpha-defensins and LL-37, as well as of beta-defensins, are discussed in the context of their specific tissue locations in the junctional epithelium and oral epithelium, respectively.

© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Figures

Fig. 1

Illustrated is the oral epithelium made up of oral gingival epithelium (OGE), oral sulcular epithelium (OSE), connective tissue (CT) and junctional epithelium (JE). The close up of the junctional epithelium exemplifies a polymorphonuclear neutrophil (PMN) degranulating upon bacterial stimulation. The contents released contain both human neutrophil peptides (HNP) that include α–defensin and cathelicidin LL-37 that act either directly or on epithelial cells to recruit more PMN into areas of bacterial insult.

Fig. 2

Illustrated is the oral epithelium made up of oral gingival epithelium (OGE), oral sulcular epithelium (OSE), connective tissue (CT) and junctional epithelium (JE). The close up of the OGE displays the stratified sections of the keratinized cells that are comprised of stratified corneum (SC), stratified spinosum (SS), stratified granulosum (SG) and stratified basal (SB) epithelial cells. Human β–defensins (HBD) are expressed in the OSE within specific stratified layers. Expression of HBD leads to infiltration of polymorphonuclear neutrophils (PMN), T-cells, Langerhans dendritic cells (DC) and mast cells into the stratified epithelium.