Pathogenic mechanisms of organisms virulent to the eye.

Gonococci possess long range adhesins in the form of pili permitting initial contact with conjunctival cells. Subsequently sticky surface protein (Protein II) bonds the gonococcus close to the host cell surface. Damage is mediated both by the intracellular uptake and the introduction of pores in the host cell membrane. Unlike gonococci, pseudomonas can only attach to damaged cells but once the eye is invaded a wide range of enzymes and toxins leads to rapid tissue destruction. The mechanisms by which Chlamydia trachomatis induce trachoma are ill-understood but involve intense antigenic stimulation. Methods are now available to investigate the antigenic structure of chlamydia at sub-molecular levels; such an approach is required for the development of a vaccine against trachoma.