Role of lymphocyte and antibody in the pathogenesis of immune-mediated herpetic uveitis

An improved technique for the diagnosis of viral retinitis from samples of aqueous humor and vitreous

We applied the technique of DNA amplification with the polymerase chain reaction to nine aqueous humor and five vitreous samples from HIV-1-infected patients with clinically diagnosed cytomegalovirus retinitis. For the amplification, recently published primers specific for herpes simplex virus (HSV), varicella zoster virus (VZV) and cytomegalovirus (CMV-1) were used. Additionally, a newly developed primer pair specific for the main immediately early gene of CMV (CMV-2) was selected and compared with the published one. All primers were tested on noninfected and HSV-, VZV- and CMV-infected human fibroblast cell culture supernatant, thereby excluding cross-reactivity of the chosen primers. In none of 13 aqueous humor and six vitreous samples of healthy controls was any viral DNA amplified. Using the CMV-1 primers, we detected CMV DNA in five of nine aqueous humor and three of five vitreous samples amplifying a DNA fragment 435 base pairs in length. With the CMV-2 primers, we detected a CMV DNA fragment with a length of 110 base pairs in eight of nine aqueous humor and in four of five vitreous samples. Additionally, CMV DNA was found in three of nine urine and two of nine saliva specimens. Both CMV and HSV DNA were amplified in one aqueous sample. Varicella DNA was not detected in any of the specimens. Thus, the polymerase chain reaction is more sensitive than other comparable diagnostic tests and may provide an alternative to conventional virus isolation and in situ hybridization techniques for the laboratory diagnosis of viral ocular disease.

Differential sensitivity of cultured retinal neurons and photoreceptors to herpes simplex infection

Infection of the retina with herpes simplex virus type 1 (HSV-1) causes devastating lesions usually leading to blindness. However, the interactions between individual retinal cell types and this virus have not been well characterized, probably because of limitations posed by the complexity of the intact retina. We have now approached this problem through the use of separate, purified populations of isolated chick embryo retinal neurons and photoreceptor cells, of glial cells, and of pigmented epithelial cells. This manuscript deals with the initial part of these studies, aimed at determining the susceptibility of different retinal types to HSV-1 infection. The different cultures were exposed to HSV-1 for 3-48 hr, and cell infection was evaluated by immunocytochemical detection of viral antigens or by autoradiographic study of viral DNA replication. Practically 100% of the retinal glial cells and pigmented epithelial cells appeared susceptible to HSV-1 infection. On the other hand, as many as 70% of the neurons present in glia-free, pigment epithelium-free cultures, also appeared infected after a 24-hr exposure to the virus. Neuronal susceptibility to HSV-1 was already present in early (2-day) cultures, was time- and concentration-dependent, and led to neuronal degeneration after 24-48 hr. Neuronal infection was also corroborated by the detection of viral particles by transmission electron microscopy. Photoreceptor cells were consistently and selectively resistant to HSV-1 infection at all the concentrations and time points investigated. Both immunocytochemical and autoradiographic studies showed similar results. Photoreceptor resistance to HSV-1 appears to be selective, since they could be readily infected with RNA viruses such as vesicular stomatitis virus and influenza virus. These cell culture preparations offer an attractive system for the investigation of cellular mechanisms involved in the differential susceptibility of retinal cells to viral infection. Moreover, they could also help in the screening of treatments potentially capable of preventing and (or) curing HSV-induced retinal infection.

Clinical findings after zosteriform spread of herpes simplex virus to the eye of the mouse

When herpes simplex virus (HSV) is inoculated onto the snout of the inbred strain NIH mouse, clinical disease of the eye ensues only after a delay, due to spread of virus to the eye occurring via neural pathways. This report is concerned with the detailed description of eye disease. Physical signs observed include mydriasis, iritis and keratitis. The incidence of combinations of physical signs has been analysed by the computer and presented as pie-charts to show the complexity and evolution of the eye disease.