THE FLUORESCENT ANTIBODY TECHNIQUE IN DIAGNOSIS OF HERPES SIMPLEX KERATITIS

Studies on HSV specific IgA antibodies in lacrimal fluid from patients with herpes keratitis by solid phase radioimmunoassay

A highly sensitive solid phase radioimmunoassay (RIA) was adapted for determination of herpes simplex virus (HSV) specific IgA antibodies in lacrimal fluids. The RIA procedure was applied to examine HSV IgA antibodies in serial samples of lacrimal fluid and in sera from 14 patients with herpes keratitis. HSV-specific IgA antibodies were detected in the lacrimal fluid of the affected eye in 12 of the 14 patients. HSV IgA antibodies were also detected in the lacrimal fluid of the unaffected eye of 7 of these patients in titers lower than those found in the corresponding affected eye. Evidence for local HSV antibody production in lacrimal fluid in herpes keratitis was supported by examination for antibodies to the unrelated measles antigen. Detection of lacrimal fluid HSV IgA antibodies might be a useful adjunct in rapid diagnosis of herpes keratitis. The advantage of characterizing the local immune response as well as viral expression in the affected vs. the unaffected eye in the same individual as a model for understanding the factors leading to subclinical vs. clinical manifestations of recurrent ocular herpes virus infections will be discussed.

Isolation of herpes simplex virus from the cornea in chronic stromal keratitis

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Enzyme immunofiltration technique for rapid diagnosis of herpes simplex virus eye infections in a rabbit model

A rapid enzyme immunofiltration assay for herpes simplex virus (HSV) has been developed which is sensitive enough to detect viral antigens in eye swabs from rabbits with primary herpes keratitis. This assay employs a specially designed filter manifold to immobilize whole cells and cell debris dissociated from the swabs. Viral antigens trapped on the filters are then detected in an indirect immunoassay utilizing staphylococcal protein A conjugated with horseradish peroxidase. The assay required only 2.5 h to perform and could be read visually. Reconstruction experiments indicated that antigen from as few as 49 HSV-infected cells could be detected. Calcium alginate swabs were shown to recover more viral antigen than dacron swabs. The enzyme immunofiltration assay detected HSV antigens on 95% of the eye swabs from which infectious virus was recovered. In addition, HSV antigen was also detected in several swabs from infected eyes which did not yield infectious virus, presumably because the virus was neutralized by native antibody present in the lacrimal fluid. This enzyme immunofiltration assay technique lends itself to the elution of native antibody bound to the viral antigens, and this may be especially applicable in the diagnosis of recurrent HSV keratitis, where antiviral antibody in the lacrimal fluid may interfere with virus isolation and fluorescent-antibody or other virus detection assays.

Herpes simplex keratitis

This article reviews the current concepts for the diagnosis and treatment of Herpes simplex keratitis and its complications, discussing characteristics of the virus, the prevalence of the disease, chemical and clinical differentiation between Types I and II Herpesvirus hominis, and the many clinical presentations of Type I disease. The antiviral agents commonly in use are reviewed, covering the historical development of the drugs, indications for their use and the associated toxic and untoward reactions. An outline for the medical treatment of the different forms of Herpes simplex keratitis is given, as well as the indications for surgical intervention in the treatment of the disease. The surgical complications and results following keratoplasty are discussed.

[Diagnosis of herpetic keratitis by immunofluorescence (author's transl)]

Between December 1973 and October 1974 scrapings of the corneal epithelium of 52 patients were examined by immunofluorescence. 41 of these corneal scrapings were suitable for examination. In 31 of 38 cases with the clinical diagnosis of a herpes simplex keratitis virus-specific antigen was found by means of immunofluorescence. The procedure takes only a few hours, and shows with 81,5% correct diagnoses a high reliability; scrapings of patients without herpetic affection never revealed a positive result. In 3 of 4 cases of deep herpetic keratitis, in which the herpetic etiology could only be supposed clinically, the diagnosis was proved by immunofluorescence.

Immunoperoxidase localization of herpes zoster virus and simian virus 40 in cell culture

The immunoperoxidase technique was used in an electron microscopy study to localize the virions of herpes zoster virus and simian virus 40 in cell cultures. Intranuclear and intracytoplasmic virions of herpes zoster virus were easily and specifically identified due to intense staining by the finely granular, black reaction product. With simian virus 40, intranuclear virions were not stained, whereas intracytoplasmic particles appeared densely black. There was essentially no background staining. Advantages of this technique over the ferritin-labeled antibody method include simpler preparative procedures for reagents, greater penetrability of the antibody conjugate, and internal amplification which substantially improves the ability to localize sites of antigen-antibody reaction. We believe that the immunoperoxidase method can be successfully applied to a wide variety of problems involving viral antigens.

Rapid identification and typing of herpes simplex virus types 1 and 2 by a direct immunofluorescence technique

An immunofluorescence (FA) technique has been developed which can identify herpes simplex virus (HSV) in clinical specimens and also type the virus directly as type 1 or type 2. This test, first applied to cervicovaginal specimens obtained from 80 mice genitally inoculated with HSV, indicated a sensitivity approaching 80% in comparison to standard viral isolation methods. A similar sensitivity was found when the test was applied to 185 clinical specimens with adequate cells for staining, which were obtained from a variety of sites of patients with suspect herpetic infection. In only 1 of 6 specimens positive by both FA and culture methods was the HSV type wrongly identified by the FA technique. There were also six specimens which were negative by culture methods but positive by the FA test, indicating a specificity of 91%. It is likely that these are not instances of false-positive tests but of other factors which may have resulted in negative viral isolations by culture methods. As more specific reagents become available, it is anticipated that the FA technique will have wider usage in diagnostic laboratories for the identification and typing of HSV types 1 and 2.

Method for the preparation of a herpesvirus hominis fluorescent conjugate for direct immunofluorescence

A detailed method for the preparation, standardization and interpretation of a direct immunofluorescentherpesvirus hominis conjugate is presented.

Rapid diagnosis of herpesvirus hominis infections in superficial lesions by immunofluorescent antibody technics

Scrapings from lesions of the skin and mucous membranes of 14 patients suspected of suffering from suspected Herpesvirus hominis infections were examined by both fluorescent antibody and routine isolation techniques. There was complete correlation between results by both methods in all 14 cases, 12 being positive. No positive fluorescence was obtained from scrapings of seven control patients with a variety of skin diseases. Thirteen patients with corneal lesions were similarly investigated. Of the 10 scrapings which showed positive fluorescence, nine were confirmed by virus isolation. It is suggested that as more antiviral agents become available the application of a fluorescent antibody technique for testing virus sensitivity in tissue culture could become a practical method.