Uveal IgG distribution: regulation by electrostatic interactions.

The differential distribution of albumin and IgG within various intraocular tissues suggests that charge rather than serum concentration plays an important role in regulating the distribution of certain molecules within the eye. The presence of anionic sites within the uveal tract indirectly regulates the localization and binding of cationic IgG by electrostatic interactions. Our studies indicate that circulating cationic IgG antibodies of pI 9.0-10.0 readily traverse the fenestrated capillaries in the ciliary body/processes and choriocapillaris and bind within vessel walls and stromal anionic regions and Bruch's membrane. Since there is normally no IgG produced within the non-inflamed, quiescent eye, this regulatory mechanism is potentially important in mediating immunologic protection within the uvea.