Is the cystatin-like domain of TSL functionally active in external ocular infections and during the normal diurnal cycle?

Purpose: To test whether the cystatin-like functional domain in tear specific lipocalin (TSL) is functionally active in tears during the normal diurnal cycle and during external ocular infections.

Methods: Capillary tube collected reflex (RTF), open (OTF) and closed (CTF) eye tear samples were recovered from six normals and semi-quantitatively western blot assayed for cystatin C and TSL. CTF samples were immunoprecipitated with antibodies raised against TSL, cystatin C and other antiproteases and screened for the co-precipitation of proteases by casein and gelatin zymography.