SPREAD OF MURINE CYTOMEGALOVIRUS TO INNER OCULAR STRUCTURES FOLLOWINGDISRUPTION OF THE BLOOD RETINA BARRIER IN IMMUNOSUPPRESSED BALB C MICE/

Purpose. The aims of this study were to determine whether disruption o f the blood-retina barrier (BRB) increases spread of murine cytomegalo virus (MCMV) to the eye after intraperitoneal inoculation and whether systemic immunosuppression influences the location of MCMV in the ocul ar compartment. Methods. The BRB of the left eye of normal and immunos uppressed mice was disrupted by supraciliary inoculation of tissue cul ture medium followed 2 hours later by intraperitoneal injection of MCM V. Plaque assay of homogenized ocular tissue was used to determine the frequency of virus-positive eyes and the titer of virus in the eyes. beta-galactosidase staining of frozen sections was used to locate viru s in the eyes. Results, In nonimmunosuppressed mice, the frequency of virus isolation, as well as the titer of virus, were significantly hig her in eyes in which the BRB had been disrupted. Although the frequenc y of virus isolation was the same in both eyes of inmunosuppressed mic e, the titer of virus was significantly higher in the eye in which the BRB had been disrupted. The most striking result was that the locatio n of virus was different in the nondisrupted eyes of immunosuppressed mice than it was in the disrupted eyes of immunosuppressed mice. In th e former, virus was seen only in the outer ocular structures (conjunct iva, sclera, lacrimal gland), whereas in the latter, virus was observe d in the retina and anterior segment (iris, ciliary body) as well as t he outer ocular structures. Conclusions, The results of these studies suggest that ocular damage followed by increased spread of virus to an d within the eye during systemic infection with CMV may be one mechani sm by which development of CMV retinitis is facilitated in patients wi th acquired immune deficiency syndrome.