Expression of beta-defensin genes by human salivary glands

This study investigated expression of genes encoding human beta-defensins 1 and 2 by human salivary glands. Tissues from surgical biopsies were collected fresh onto ice and stored in liquid nitrogen. Total RNA was extracted using Trizol reagent and human beta-defensin messenger RNA detected by reverse transcriptase polymerase chain reaction amplification. DNA sequencing of amplified fragments, after ligation into pGEM-T Easy vector and transformation of competent Escherichia coli, confirmed identities of cloned fragments. Human beta-defensin 1 messenger RNA was detected in all 25 samples that generated amplifiable cDNA, as assessed using abl-specific primers. Three of 13 submandibular gland samples (two normal, one chronically inflamed), and 2 of 2 minor salivary gland samples (one normal, one chronically inflamed) expressed human beta-defensin 2 messenger RNA. All six parotid gland samples studied were negative for human beta-defensin 2 messenger RNA. Thus, human beta-defensin 1 gene expression occurred in all human major and minor salivary glands studied, whereas human beta-defensin 2 expression occurred only in a small number of gland samples.