Enzyme-linked immunosorbent assay spin amplification technique for herpes simplex virus antigen detection

Comparison of α-glucosyl hesperidin of citrus fruits and epigallocatechin gallate of green tea on the Loss of Rotavirus Infectivity in Cell Culture

A number of secondary plant metabolites (e.g., flavonoids) possess antiviral/antimicrobial activity. Most flavonoids, however, are difficult to study, as they are immiscible in water-based systems. The relatively new semisynthetic α-glucosyl hesperitin (GH), and the natural plant product epigallocatechin gallate (EGCG) are unique among most flavonoids, as these flavonoids are highly soluble. The antiviral activity of these plant metabolites were investigated using the rotavirus as a model enteric virus system. Direct loss of virus structural integrity in cell-free suspension and titration of amplified RTV in host cell cultures was measured by a quantitative enzyme-linked immunosorbent assay (qEIA). After 30 min. 100 × 10(3) μg/ml GH reduced RTV antigen levels by ca. 90%. The same compound reduced infectivity (replication in cell culture) by a similar order of magnitude 3 to 4 days post inoculation. After 3 days in culture, EGCG concentrations of 80, 160, and 320 μg/ml reduced RTV infectivity titer levels to ca. 50, 20, and 15% of the control, respectively. Loss of RTV infectivity titers occurred following viral treatment by parallel testing of both GH and EGCG, with the latter, markedly more effective. Cytotoxicity testing showed no adverse effects by the phenolic concentrations used in this study. The unique chemical structure of each flavonoid rather than each phenolic's inherent solubility may be ascribed to those marked differences between each molecule's antiviral (anti-RTV) effects. The solubility of EGCG and GH obviated our need to use potentially confounding or obfuscating carrier molecules (e.g., methanol, ethanol, DMSO) denoting our use of a pure system environ. Our work further denotes the need to address the unique chemical nature of secondary plant metabolites before any broad generalizations in flavonoid (antiviral) activity may be proposed.

Spin-amplified culture followed by enzyme immunoassay for detection of herpes simplex virus in patient specimens: a comparative study

In a comparative study it was found that a combination technique of spin-amplified culture and detection of herpes simplex virus (HSV) antigen in 48-h incubated cell culture lysate by a HSV antigen detection enzyme immunoassay kit (Dupont Herpchek) detected the largest number (227) of confirmed HSV positives when compared to standard cell culture (191) and direct Herpchek (146) on the same 415 clinical specimens.

The effect of rolling and orbital motion on herpesvirus replication in tube cultures and shell vials

BACKGROUND

Isolation of viruses from clinical specimens remains a viable diagnostic manoeuvre but positive isolation rates may be low and time to observe cytopathic effects (CPE) may be longer than preferred for optimal management. Both shell vial (SV) centrifugation and rolling of conventional tube cultures (TC) have been used to enhance the isolation process.

OBJECTIVES

To determine the effect of rolling and orbital motion on the replication of herpes simplex virus (HSV) and cytomegalovirus (CMV) TC and SV.

STUDY DESIGN

TC were inoculated with HSV or CMV at varying dilutions and subjected to rolling or incubated stationary. Samples were selected to determine the impact of motion on viral yield, time to CPE according to initial multiplicity of infection (MOI) and stage of the infection process. Similar studies were performed with SV centrifuged with virus followed by stationary incubation or not centrifuged but incubated on an orbital shaker.

RESULTS

Rolling HSV-infected TC 383 rotations per minute (RPM) (30.2 x g) for 4 days enhanced viral yields by 53-fold over TC without motion. The optimal RPM response for HSV replication occurred at 96 RPM (1.9 x g) where an 89-fold increase in viral yield was detected, P < 0.01. One-step growth studies at 0,2 and 96 RPM demonstrated enhancement of HSV replication at 2 and 96 RPM. TC infected with HSV at low MOI and rolled at 96 RPM had more CPE-positive cultures after 1-3 days than controls. Late in the infection process, no differences in CPE-positive were detected between rolled and non-rolled TC. Studies with CMV and rolling at 96 RPM resulted in more positive TC and greater CPE. SV that were not centrifuged but incubated for 16 h on an orbital shaker had significantly more HSV foci than those handled by a conventional SV method.

CONCLUSION

Our studies indicate that orbital motion and motion yielding a force near [Formula: see text] enhances the isolation and growth of HSV and CMV in TC and SV.

Physical and chemical methods for enhancing rapid detection of viruses and other agents

Viral replication events can be enhanced by physical, chemical, or heat treatment of cells. The centrifugation of cells can stimulate them to proliferate, reduce their generation times, and activate gene expression. Human endothelial cells can be activated to release cyclo-oxygenase metabolites after rocking for 5 min, and mechanical stress can stimulate endothelial cells to proliferate. Centrifugation of virus-infected cultures can increase cytopathic effects (CPE), enhance the number of infected cells, increase viral yields, and reduce viral detection times and may increase viral isolation rates. The rolling of virus-infected cells also has an effect similar to that of centrifugation. The continuous rolling of virus-infected cultures at < or = 2.0 rpm can enhance enterovirus, rhinovirus, reovirus, rotavirus, paramyxovirus, herpesvirus, and vaccinia virus CPE or yields or both. For some viruses, the continuous rolling of infected cell cultures at 96 rpm (1.9 x g) is superior to rolling at 2.0 rpm for viral replication or CPE production. In addition to centrifugation and rolling, the treatment of cells with chemicals or heat can also enhance viral yields or CPE. For example, the treatment of virus-infected cells with dimethyl sulfoxide can enhance viral transformation, increase plaque numbers and plaque size, increase the number of cells producing antigens, and increase viral yields. The infectivity of fowl plague virus is increased by 80-fold when 4% dimethyl sulfoxide is added to culture medium immediately after infection. The heat shocking of virus-infected cells also has been shown to have a stimulatory effect on the replication events of cytomegalovirus, Epstein-Barr virus, and human immunodeficiency virus. The effects of motion, chemicals, or heat treatments on viral replication are not well understood. These treatments apparently activate cells to make them more permissive to viral infection and viral replication. Perhaps heat shock proteins or stress proteins are a common factor for this enhancement phenomenon. The utility of these treatments alone or in combination with other methods for enhancing viral isolation and replication in a diagnostic setting needs further investigation.

Diagnostic virology--then and now

In the past five years, technologic advances in the shell vial assay and expanding availability of rapid membrane EIA tests have allowed over 90% of the viruses detected in our laboratory to be reported within 24 h postinoculation. PCR technology promises to add a new practical dimension to diagnostic virology especially for the detection of viruses in CSF, tissues, and blood. Extension of these diagnostic capabilities from investigative protocols to general laboratories for routine use will be our biggest challenge and be based on considerations of cost, licensing, and availability of this technology in "kit" formats.

Detection of herpes simplex virus by the Kodak SureCell Herpes Test

The Kodak SureCell Herpes Test Kit (SC-HSV) was evaluated in a high-risk sexually transmitted disease clinic population. A total of 97 lesion specimens (from 94 patients) were tested for the presence of herpes simplex virus by SC-HSV and by spin-amplified tissue culture confirmed by an enzyme immunoassay. The overall sensitivity of SC-HSV compared with that of spin-amplified tissue culture-enzyme immunoassay was 81.1%; the specificity was 100%. For vesicular lesions only, SC-HSV sensitivity was 100%; for nonvesicular lesions, sensitivity was 75.6%, SC-HSV was rapid (less than 15 min) and very easy to perform.

Continuous high-speed rolling versus centrifugation for detection of herpes simplex virus

Specimens submitted for diagnosis of herpes simplex virus infections were inoculated into shell vials and conventional culture tubes. Inoculated culture tubes were incubated with rolling at 96 rpm. Immunoperoxidase (IP) staining and cytopathic effects (CPE) were used to detect positive cultures. At 24 h, 42 (53%) of the rolled cultures were positive for CPE, while only 16 (21%) of the shell vials were CPE positive (P less than 0.01). No difference in sensitivity was seen between rolled and shell vial cultures that were inoculated with high-titered viral preparations and IP stained at 16 h. However, when low-titered preparations were used, 39 of 41 (95%) were IP positive by the high-speed roller method at 64 h postinoculation, while only 24 of 41 (58%) were IP positive with shell vials (P less than 0.01). These results indicate that high-speed roller method at 64 h postinoculation, while only 24 of 41 (58%) were IP positive with shell vials (P less than 0.01). These results indicate that high-speed rolling is better than the shell vial technique for the detection of herpes simplex virus by IP staining.

Amplification techniques for detection of herpes simplex virus in neonatal and maternal genital specimens obtained at delivery

Viral culture amplification methods, including centrifugation, use of a cell pretreatment medium containing dimethyl sulfoxide and dexamethasone (DEX medium), and three commercial enzyme immunoassays (EIAs), were evaluated for use with low-titer, asymptomatic neonatal and obstetric samples obtained at delivery. The 4.5-h Ortho EIA was 59.7% sensitive at 16 h compared with 86.4% at 36 h in a spin-amplified format (SAT-EIA). After 36 h with DEX medium, the SAT-EIA was 97.3% sensitive using the 2.5-h modified Ortho EIA and 69.9% sensitive using the Fairleigh Dickinson EIA. Herpes simplex virus (HSV) cytopathic effect was reported in tube culture 1 to 2 days earlier in 8.1 to 35.9% of cells with DEX medium. Overall, the SAT-EIA using the modified Ortho EIA and cells with DEX medium detected 147 of 153 (96.1%) HSV isolates from samples obtained predelivery and 93.1% of 29 HSV positives from samples obtained at labor and delivery, with specificities of 100 and 99.9%, respectively, at 36 h.

Rapid detection of herpes simplex virus with fluorescein-labeled Helix pomatia lectin

The use of fluorescein-conjugated Helix pomatia lectin was shown to be as effective as fluorescein-conjugated monoclonal antibody reagents for the detection and differentiation of herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) in MRC-5 cell culture. Cells infected with HSV-1 generally displayed a pattern of nongranular or diffuse fluorescence, while cells infected with HSV-2 were identified by the production of fluorescent grains and flecks. This unique nonimmunological reagent, when used in combination with low-speed centrifugation, provides a remarkably specific, sensitive, rapid, and cost-effective means to detect HSV-infected MRC-5 or BHK-21 cells as early as 20 h postinoculation. In contrast to the immunofluorescence method, the serotypes of HSV can be differentiated with only one fluorescein-H. pomatia reagent in MRC-5 cell cultures.

Rapid and accurate viral diagnosis

In recent years, there has been increased recognition of the importance of viral infections. In addition, new antiviral agents have become available. These factors have led to a marked increase in utilization of viral diagnostic services. In this review, both conventional and rapid methods for viral diagnosis are presented, with emphasis on recent advances. The antiviral agents currently available and the major drugs under investigation are also briefly discussed. It is hoped that this review will serve as a useful adjunct for the management of patients with virus infections.

Modified spin-amplified adsorption procedure with conventional tissue culture tubes for rapid detection and increased recovery of herpes simplex virus from clinical specimens

Conventional culture tubes were used in a modification of the spin-amplified adsorption procedure for recovery of herpes simplex virus (HSV) from clinical specimens. The sensitivity of isolation of HSV from 864 specimens adsorbed by the spin-amplified method was 100% (127 of 127), compared with 88.2% (112 of 127) for stationary-phase-adsorbed specimens. Cytopathic effect developed more rapidly in 32.1% (36 of 112) of isolates adsorbed by spin amplification than in those adsorbed by stationary means. In a separate quantitative study, cultures of HSV type 1 adsorbed by spin amplification yielded higher antigen levels and greater cytopathic effect than stationary-phase-adsorbed cultures. Cells grown in conventional tissue culture tubes may be used in a spin-amplified adsorption for rapid detection and increased sensitivity of HSV isolation.

New diagnostic tests for herpes simplex and varicella zoster infections

Laboratory tests for herpetic infections can be divided into (1) morphologic, (2) immunomorphologic, (3) serologic, and (4) virologic. Tzanck smears are easy to do, inexpensive, and compare favorably with cultures and immunofluorescence tests for specificity and sensitivity, but they require considerable experience to interpret accurately and they cannot differentiate between herpes type 1, herpes type 2, and varicella zoster infections. Biopsies are useful when clues to a diagnosis are being sought. Peroxidase-antiperoxidase and avidin-biotin tests present technical difficulties but interpretational difficulties are low and the results are available in a few hours. They can distinguish between herpes type 1, herpes type 2, and varicella zoster virus, as can immunofluorescence using monoclonal antibodies. Serologic tests are used primarily to distinguish between primary and recurrent herpes simplex infections. Virus isolation in tissue cultures is the gold standard for identifying herpes simplex virus but it is not 100% specific or 100% sensitive. Restriction endonuclease analysis identifies types and strains of virus by their deoxyribonucleic acid composition and it is very useful in epidemiologic studies. Ability to find virus by whatever method is influenced by the stage of the lesion. As lesions age, less infectivity and antigen result in less sensitivity of the tests.

Evaluation of a rapid latex slide agglutination test for herpes simplex virus as a specimen screen and culture identification method

A total of 449 clinical specimens and 199 culture fluids were tested using the Virogen Herpes Slide Test (Wampole Laboratories, Div. Carter-Wallace, Inc., Cranbury, N.J.), a rapid latex agglutination procedure. The results were compared with those obtained with isolation of herpes simplex virus in cell culture followed by identification using immunoperoxidase or fluorescent reagents. The sensitivity, specificity, and positive and negative predictive values of the direct test were 49.7, 93.4, 96.0, and 37.1%, respectively. The sensitivity and specificity of the latex agglutination test for culture confirmation were 75.9 and 100%, respectively.