Beta defensin precursors are more simple in structure than those of alpha defensins, having a signal sequence, a short or absent propiece and the mature defensin sequence at the C-terminus. The signal sequence is cleaved off by a signal peptidase in the endoplasmic reticulum (Ganz 2003). Mature beta defensins 1, 2, 3, and 4 are secreted primarily by epithelial cells but are also produced by some immune cells such as monocytes, macrophages and dendritic cells (Duits et al. 2000, Ryan et al. 2003).