Abstract
Purpose :
Diseases of the cornea may be treated by systemic administration of drugs but topical application is the preferred method because it minimizes off-target exposure and allows more aggressive treatments. However, the ocular surface has very efficient clearance mechanisms including blinking and tear flow, which leaves the topical application of biologics generally ineffective because they are washed out too quickly to have significant therapeutic effects. We explored the idea that attaching a module that binds to the ocular surface and serves as an “anchor” to extend the residency time of biologics on wet epithelia and enhance their effective use in the disease setting even with infrequent application.
Methods :
We conjugated antibodies to wheat germ agglutinin which binds GlcNAc and sialic acid that are ubiquitously present in the cornea using standard EDC(1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide)/sulfo-NHS(N-hydroxysulfosuccinimide)
cross-linking. Binding of AlexaFlour 488- labeled ligands was assessed by binding to antibodies immobilized on GlcNAc beads. Antibody to IL-17A was labeled with AlexaFluor 488 and the retention was followed by fluorescent imaging. The main extraorbital lacrimal glands of C57Black/6 were surgically removed to establish dry eye. The effects of application on the integrity of the corneal surface were monitored by fluorescein staining. Histological samples were scored for the number of infiltrating limbal CD4+ cells, epithelial thickness and disorganization, and disruption of innervation. Scoring was done by masked observers.
Results :
Conjugation to wheat germ agglutinin did not compromise binding of antibodies to their cognate ligands. The anchor increased the ocular surface half-life by 350-fold upon application to eyes in a murine dry eye model. Antibodies to IL-17A, IL-23, and IL-1β conjugated to the agglutinin reduced manifestations of dry eye, even when applied once daily, whereas unconjugated antibodies were ineffective. Conjugated antibodies to IL-6, TNFα, and IFNγ had no effects.
Conclusions :
Attaching an anchor such as wheat germ agglutinin to antibodies and, presumably, other biologics is a simple and feasible method to overcome washout and expand the therapeutic potential of topical ophthalmics for use in ocular surface disease.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.