Pseudorabies virus glycoprotein L is necessary for virus infectivity but dispensable for virion localization of glycoprotein H.

Herpesviruses contain a number of envelope glycoproteins which play important roles in the interaction between virions and target cells. Although several glycoproteins are not present in all herpes simplex viruses, others, including glycoproteins H and L (gH and gL), are conserved throughout the Herpesviridae. To elucidate common properties and differences in herpes simplex virus glycoprotein function, corresponding virus mutants must be constructed and analyzed in different herpes simplex virus backgrounds. Analysis of gH- mutants of herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PrV) showed that in both viruses gH is essential for penetration and cell-to-cell spread and that its presence is required for virion localization of gL. Since gH homologs are found complexed with gL, it was of interest to assess the phenotype of gL- mutant viruses. By using this approach, HSV-1 gL has been shown to be required for entry and for virion localization of gH (C. Roop, L. Hutchinson, and D. Johnson, J. Virol. 67:2285-2297, 1993). To examine whether a similar phenotype is associated with lack of gL in another alphaherpes virus, PrV, we constructed two independent gL- PrV mutants by insertion and deletion-insertion mutagenesis. The salient findings are as follows: (i) PrV gL is required for penetration of virions and cell-to-cell spread; (ii) unlike HSV-1, PrV gH is incorporated into the virion in the absence of gL; (iii) virion localization of gH in the absence of gL is not sufficient for infectivity; (iv) in the absence of gL, N-glycans on PrV gH are processed to a greater extent than in the presence of gL, indicating masking of N-glycans by association with gL; and (v) an anti-gL polyclonal antiserum is able to neutralize virion infectivity but did not inhibit cell-to-cell spread. Thus, whereas PrV gL is essential for virus replication, as is HSV-1 gL, gL- PrV mutants exhibit properties strikingly different from those of HSV-1. In conclusion, our data show an important functional role for PrV gL in the viral entry process, which is not explained by a chaperone-type mechanism in gH maturation and processing.

Viral diagnosis of neurological infection by RT multiplex PCR: a search for entero- and herpes simplex viruses in a prospective study.

The diagnosis of a wide range of different neurological syndromes was established by a reverse transcription multiplex PCR assay. The presence of enterovirus and herpes simplex viruses was studied in cerebrospinal fluid samples collected prospectively from 200 patients hospitalized with neurological diseases suspected of viral infection. Positive PCR results for enterovirus and neurotropic herpes simplex virus (herpes simplex, HSV, and varicella zoster, VZV) were obtained among the immunocompetent patients (55/156, 35%) who presented aseptic meningitis or encephalitis. Among immunocompromised patients the yield of positive PCR results was 41% (18/44), predominantly lymphotropic herpes simplex viruses (15/44, 34%). Cytomegalovirus (CMV) DNA was detected in patients with several clinical syndromes, including encephalitis, chronic meningitis, retinitis, ventriculitis, polyradiculomyelitis, and myeloradiculitis. Epstein-Barr (EBV) and VZV-specific DNA sequences were detected in patients with either encephalitis, aseptic meningitis, and chronic meningitis. Dual infections of CMV and HSV or CMV and EBV were established in two AIDS patients with encephalitis and polyradiculomyelitis, respectively. The applications of this RT multiplex PCR assay are extensive and may prove to be particularly valuable for the rapid and sensitive diagnosis of neurological diseases in both immunocompetent and immunocompromised patients.

Detection of oyster herpes simplex virus DNA and proteins in asymptomatic Crassostrea gigas adults.

Since 1972, several herpes-like virus infections have been reported among different bivalve species around the world. Most of these reports involved larvae or juveniles presenting high mortalities. Two case reports of herpes-like viruses concerned adult oysters, Crassostrea virginica in USA and Ostrea angasi in Australia. Molecular techniques including PCR and in situ hybridization (ISH) have been recently developed to detect the oyster herpes simplex virus genome. In the present study, 30 Pacific oyster, Crassostrea gigas, adults have been analyzed using three different techniques: PCR, ISH and immunochemistry, in order to detect herpes simplex viruses in asymptomatic individuals. PCR and ISH allowed detection of oyster herpes simplex virus DNA in 93.3 and 86.6%, respectively, of analyzed oysters while polyclonal antibodies allowed detection of viral proteins in 76.6% of analyzed adult oysters. These results suggest that oyster herpes simplex virus infects adult oysters with high prevalence and that the virus may persist in its host after primary infection. The detection of viral DNA and viral proteins in the gonad of several individuals supports the hypothesis of a possible vertical transmission of the infection. Lastly, concordance among the three techniques used in this study is discussed.

Rapid diagnosis of ocular herpes simplex infections.

BACKGROUND--The Surecell herpes simplex (HSV) test kit is a test for detecting the presence of herpes simplex viral antigen by means of a monoclonal antibody based immunoassay. The test has proved to be highly sensitive and specific in diagnosing genital, oral, and dermatological herpes simplex infections. METHODS--In this study, samples from patients with ocular keratitis were evaluated by tissue cultures and the Surecell test. The eyes of New Zealand rabbits were then inoculated with HSV type 1 acute keratitis, acute Staphylococcus keratitis, and HSV type 1 postkeratitis (healed corneas). Tear film samples collected from each eye with a cotton swab were evaluated by routine culture (A-549 monolayers) and by the Surecell test with and without prior placement of the swab in Hank's medium. RESULTS--The Surecell system had a 70% sensitivity and a 100% specificity in the detection of HSV antigen in ocular infections, and was shown to be a quick, efficient, and accurate method of testing for HSV antigen in humans. CONCLUSION--These results from humans and rabbits indicate that the Surecell test, which requires no special equipment, can be a useful in office adjunct in the clinical diagnosis of ocular herpes simplex.