Evaluation of five monoclonal antibody-based kits or reagents for the identification and culture confirmation of herpes simplex virus

The clinical spectrum and therapeutic challenge of eczema herpeticum

We present 5 cases of eczema herpeticum in patients with severe recalcitrant atopic dermatitis to illustrate the range of possible clinical findings and supporting laboratory data that can obscure the diagnosis and complicate treatment. Major issues include: the need for aggressive laboratory evaluation (molecular diagnostics, viral cultures, skin biopsy, serology); the possibility of recurrent or chronic infection; the value of empiric antiviral therapy; the possibility of infection with thymidine-kinase resistant strains; and the importance of achieving control over the dermatitis with nonmyelosuppressive immunomodulating agents such as intravenous immunoglobulin or interferon gamma for dermatitis that requires systemic treatment.

Detection of cutaneous herpes simplex virus infections by immunofluorescence vs. PCR

BACKGROUND

Detection of cutaneous infections with herpes simplex virus (HSV) has proven difficult, as serum antibody tests sometimes are not sensitive and specific enough for that purpose.

OBJECTIVE

This study was conducted to compare the sensitivity for detection of HSV of an immunofluorescence method (Syva Microtrak) and an internally controlled PCR.

METHODS

Cutaneous swabs from skin lesions were analysed by immunofluorescence separately for HSV types 1 and 2 and by competitive PCR. Detection of PCR products was done by ELISA, if positive additionally by agarose gel electrophoresis.

RESULTS

Of 79 samples 34 were PCR-positive by ELISA (34 = 100%), of which 23 (68%) were also positive on the agarose gel. Eleven samples (32%) were positive by immunofluorescence. No sample was positive by immunofluorescence and negative by PCR.

CONCLUSIONS

These results demonstrate that immunofluorescence using Syva Microtrak is not suitable for exclusion of herpes simplex virus infection as sensitivity was only 32%. However, as immunofluorescence is cheaper and faster than PCR, first screening can be done with immunofluorescence, and negative samples can be investigated by PCR to finally prove or exclude the presence of HSV DNA.

Typing of clinical herpes simplex virus type 1 and type 2 isolates with monoclonal antibodies

The purpose of this study was to evaluate the performance of a herpes simplex virus (HSV) type 1-specific anti-glycoprotein C-1 monoclonal antibody (MAb) and a type 2-specific anti-glycoprotein G-2 MAb for typing of 2,400 clinical HSV-1 isolates and 2,400 clinical HSV-2 isolates, respectively, using an enzyme immunoassay. The anti-HSV-1 MAb showed sensitivity and specificity of 100%, and the anti-HSV-2 MAb showed a sensitivity of 99.46% and 100% specificity, indicating that these MAbs are suitable for typing of clinical HSV isolates.

Cytospin-enhanced direct immunofluorescence assay versus cell culture for detection of herpes simplex virus in clinical specimens

The reliability of a cytospin-enhanced direct immunofluorescence assay (DFA), using Syva Micro Trak monoclonal antibodies, for detection of herpes simplex virus (HSV) was evaluated by comparing results with those of conventional cell culture. Of 250 clinical specimens, 64 were positive for HSV by cell culture, and 22 were positive by cytospin-enhanced DFA, two of which were negative by culture. The sensitivity, specificity, and positive and negative predictive values for cytospin-enhanced DFA were 31.25, 98.9, 90.9, and 80.7%, respectively. Cytospin-enhanced DFA is not an acceptable alternative to cell culture for detection of HSV.

Detection and typing of herpes simplex viruses by using recombinant immunoglobulin fragments produced in bacteria

Thirty-seven bacterial clones producing human recombinant monoclonal antibody Fab fragments (rFabs) reactive to herpes simplex virus (HSV) antigens were selected from a human combinatorial antibody library constructed in a phage-display vector by a panning procedure against an HSV lysate. Thirty-four of the HSV-specific rFabs were able to specifically recognize HSV-infected cells in indirect immunofluorescence (IF) assays; of these, 25 recognized cells infected by either HSV type 1 (HSV-1) or HSV-2, while 9 recognized only HSV-1-infected cells. One HSV type-common rFab (rFab H37) and one HSV-1-specific rFab (rFab H85) were further evaluated as reagents for viral detection and typing by IF staining in 134 HSV-positive (72 HSV-1 and 62 HSV-2) viral cultures from clinical specimens. The results obtained with these two rFabs were fully consistent with those obtained with a commercial preparation of fluorescein-labeled anti-HSV type-specific murine monoclonal antibodies. The detection sensitivity with the type-common rFab in indirect IF assays was higher overall than that provided by the type-specific murine monoclonal antibodies. Preparations of rFabs suitable for IF staining can be easily and inexpensively obtained in a clinical microbiology laboratory from Escherichia coli cultures. Similar HSV-specific rFabs, therefore, could be advantageous for in vitro diagnostic purposes.

Direct immunofluorescence vs. culture for detecting HSV in oral ulcers: a comparison

Diagnostic tests may be necessary to determine the cause of oral ulcers. Direct immunofluorescence staining of oral smears supplies results much more quickly than viral culture, the "gold standard" for diagnosing HSV lesions. This study compares the sensitivity and specificity of direct immunofluorescence staining vs. viral culture and evaluates the usefulness of the two techniques for the general dental practitioner.

Presumptive identification of common adenovirus serotypes by the development of differential cytopathic effects in the human lung carcinoma (A549) cell culture

The neutralization test is commonly used in clinical virology laboratories for the identification by serotype of adenovirus isolates. In an effort to conserve reagents and reduce the amount of time in the performance of this assay, we evaluated the significance of differential cytopathic effects for the presumptive identification of lower-numbered adenovirus serotypes that are commonly encountered in the clinical setting. Utilizing the human lung carcinoma (A549) cell culture as our indicator system, two viral induced monolayer degenerations (i.e., cytopathic effects or CPEs) were recognized. Among our wild and the laboratory adapted (i.e., ATCC) adenovirus isolates tested in this study, serotypes 1, 2, 4, 5, 6, 8, 11, 19, 21, 27, and 31 were expectedly characterized by the typically enlarged, rounded, and refractile cells, which eventually aggregated into irregular 'grape-like' clusters. Adenovirus types 3 and 7, however, were characterized by the development of distinct intranuclear inclusions, a flattening and then a web or net-like monolayer degeneration. Differences in the intensity of intranuclear granulation were related by electron microscopy to differences in the quantity of viral crystalline aggregates within the host cell nucleus. A presumptive identification of the commonly encountered adenovirus serotypes 3 and 7 prior to the performance of the neutralization test would result in a conservation of type-specific antiserum, a decreased use of cell cultures and medium, and lastly, reduced medical technologist workload.

Laboratory techniques in the diagnosis of herpes simplex infection

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Comparative evaluation of four commercially available monoclonal antibodies for culture confirmation of herpes simplex virus infection

Four fluorescein isothiocyanate-labelled monoclonal antibody typing reagents were compared for intensity of fluorescence and sensitivity in confirming herpes simplex virus (HSV) in cell culture. A total of 125 (50 HSV type 1 [HSV-1] and 75 HSV-2) specimens positive for HSV were concurrently stained with type-specific monoclonal antibodies from Bartels (Bartels Immunodiagnostic Supplies, Inc., Bellevue, Wash.), Kallestad (Pathfinder; Kallestad Diagnostics, Chaska, Minn.), Diagnostic Products Corp. (DPC) (PathoDx; DPC, Los Angeles, Calif.), and Syva (Microtrak; Syva Co., Palo Alto, Calif.). Fifty cultured specimens not displaying HSV-associated cytopathic effect were also stained. Each of the four reagents confirmed the 50 negative cultures and 125 positive cultures. One HSV-1-positive culture was missed by the Kallestad antibody. Ten HSV-1 isolates displayed dull fluorescence when stained with the Syva HSV-2 reagent. The other three reagents stained only the HSV-1 well with these 10 specimens. The Syva and Bartels stains were brighter, in general, than the Kallestad and DPC stains. However, the Kallestad and DPC stains were brilliant enough to allow interpretation without hesitation. The differences in intensity and background staining emphasize the need for laboratories to routinely perform quality checks on their reagents and to test new products which become commercially available.