Expression of alpha- and beta-defensins in human ocular surface tissue.

PURPOSE: Defensins are antimicrobial peptides and are classified into three groups, alpha-, beta- and theta-defensins. We investigated the localization of human neutrophil peptides (HNP) 1-3, which are members of the alpha-defensin subfamily, and the expression of human beta-defensin 1 (hBD-1) and hBD-2 in the ocular surface tissues.
METHODS: Corneal or conjunctival tissues were obtained from 17 patients undergoing surgery. The reasons for surgery were thermal burns (two patients), acid burn (one patient), corneal perforation (one patient), corneal abscess (one patient), and pterygium (two patients). As a control, tissue samples were collected from ten patients undergoing cataract surgery. The samples were examined for HNP 1-3 by immunohistochemical analysis, and for hBD-1 and hBD-2 by the reverse transcriptase-polymerase chain reaction (RT-PCR) method.
RESULTS: Results of staining for HNP 1-3 were positive in all of the six tested samples. The RT-PCR method detected hBD-1 mRNA in all samples. However, hBD-2 was detected in only 7 of the 17 samples. In eight of the ten normal conjunctiva samples and in the two samples from conjunctiva with thermal burn or pterygium, hBD-2 mRNA was not detected.
CONCLUSIONS: We concluded that HNP 1-3 and hBD-1 are constitutively expressed in the ocular surface. However, hBD-2 may or may not be expressed, depending on the stage of ocular surface diseases.