An in-vitro evaluation of lectin cytotoxicity using cell lines derived from the ocular surface.

Lectins are proteins or glycoproteins of non-immune origin capable of binding to one or more specific sugar residues. The potential for using lectins as a means of locating and "anchoring" a drug delivery system to a target site on a mucosal surface in order to promote controlled drug delivery and enhanced absorption has been described in previous work. Toxicity is evident for many lectins, and this study has investigated the cytotoxicity of lectins to cells derived from the cornea and conjunctiva. Cultures of transformed cell lines from the conjunctiva and cornea were exposed to solution of lectins, and the viability of these cells assessed by their ability to take up an MTT stain relative to the control. Clear evidence of lectin cytotoxicity was apparent for all of the lectins tested in this study, particularly at higher concentrations and over the longer (48 h) time period. This would raise issues with their potential use in targeted drug delivery systems. The lectins from Lycopersicon esculentum and Helix pomatia appeared to show the least cytotoxic activity and so could be considered the most promising. The lectins from Solanum tuberosum and Triticum vulgaris showed significant cytotoxicity, which contrasts with previous in-vivo studies. However, they might be considered for investigation as targeted therapeutic agents in the treatment of malignant diseases.