The Effects of Transferrin Receptor Antibody,Transferrin Receptor Antibody Bound to Pseudomonas Exotoxin and Transforming Growth Factor-α Bound to Pseudomonas Exotoxin on Human Tenon's Capsule Fibroblast Proliferation

Abstract

ABSTRACT

Pharmacological agents which modulate the wound healing process by the inhibition of proliferation of fibroblasts may improve the success of glaucoma filtration surgery. Since cell proliferation is essential to the wound healing process, we targeted the surface receptors that are associated with proliferating cells. We present the effects of three such agents--purified mouse anti-human transferrin receptor monoclonal antibody 42/6 (anti-TfR-42/6), anti-transferrin monoclonal antibody bound to a Pseudomonas exotoxin (anti-TfR-PE40) and transforming growth factor-α Pseudomonas exotoxin (TGF-α-PE40)--on human fibroblasts from Tenon's capsule. The inhibition of human subconjunctival fibroblast proliferation by anti-TfR-42/6 (with a concentration up to 25 μg/ml) and by anti-TfR-PE40 and TGF-α-PE40 (both with a concentration range of 5000-0.00001 μg/ml) was determined by colorimetric (OD), and cell counting (CC) assays over a 9-day period. Neither anti-TfR-42/6 nor anti-TfR-PE40 had an antiproliferative effect on the fibroblasts. TGF-α-PE40 demonstrated an antiproliferative effect in a dose response manner. The mean 50% inhibitory dose (ID₅₀) by OD was 32.91 μg/ml, while the ID₅₀ by CC was 27.88 μg/ml. EGF was used as a negative control for TGF-α-PE40 toxin. The inhibitory effect of the toxin conjugate was completely blocked by the addition of 1000 μg/ml of EGF. These in vitro studies show that TGF-α-PE40 may be useful in modulating the proliferation of human ocular fibroblasts; they also give some indication of drug dosages for future in vivo testing.