Diffusion of immunoglobulin G from the vascular compartment into the normal rabbit cornea

In order to study the rate of entry of IgG into the normal cornea, IgG specific for human serum albumin was injected intravenously over a 2-month period into nonimmunized rabbits. The concentrations of total immunoglobulin G (IgG) and IgG specific for human serum albumin in serum, corneal tissue, and aqueous humor were determined with enzyme-linked immunosorbent assays. The experiments showed that the corneal concentration of IgG specific for human serum albumin increased by approximately 1% per day, whereas the total IgG concentration of the corneas used in this study was 70% of the concentration detected in serum. On the basis of these data it was hypothesized that an equilibrium between the serum and corneal IgG concentration was established after approximately 70 days. By injecting IgG preparations with different isoelectric point ranges, the influence of electrostatic interactions on the rate of entry into the cornea was investigated. It was found that charge had no effect on diffusion. From these results it was concluded that, after an antigenic stimulation, newly synthesized antibodies will be confined to the limbal region and will be noted only gradually at points nearer to the center. This indicates that the role of IgG during the immediate inflammatory response of the cornea is limited.