Identification and typing of herpes simplex virus by enzyme immunoassay with monoclonal antibodies

Clear detection and typing of herpes simplex virus types 1 and 2 by an indirect ELISA assay: comparison with three different combined methods--capture ELISA, restriction enzymes, and polymerase chain reaction

The severity and recurrences of Herpes Simplex Virus (HSV) infection depend on the type of the infectious agent (HSV-1 or HSV-2), which induces the necessity of a nonambiguous detecting typing. The commonly used capture ELISA technique has to be often supported by DNA analysis to confirm the detection and the typing of HSV viruses in exposed patients. In this report, we describe a rapid and cheap indirect ELISA method using anti-HSV monospecific polyclonal antibodies prepared in the laboratory. The typing of the studied samples was clear, did not need series of dilution, and allowed the immediate classification of viruses without further control examination. We tested 51 specimens, which were typed 25 HSV-1 and 26 HSV-2 strains. The comparison with capture ELISA, restriction enzyme and polymerase chain reaction analysis definitely allowed our method to be assessed as a useful tool for a routine diagnostic.

Rapid detection, culture-amplification and typing of herpes simplex viruses by enzyme immunoassay in clinical samples

BACKGROUND

The laboratory diagnosis of herpes simplex infection may require rapid (direct) tests, as well as cell cultures, for detection of the virus in clinical samples. The quantity of virus present in clinical samples is variable and this may depend on the period from onset of rash. In addition, not all patients may show obvious symptoms with this infection. The successful culture of herpes simplex virus requires prompt transportation after collection of the specimen as the virus is easily inactivated. Hence, rapid and culture tests would enable detection of non-viable and viable viruses.

STUDY DESIGN

We describe the rapid detection of HSV by EIA directly in various clinical samples using commercially available polyclonal sera. In addition specimens were inoculated in microwell cell cultures and 4 days post inoculation the culture fluids were tested for HSV and subtyped by a similar EIA (culture amplified EIA).

RESULTS

The direct EIA showed an endpoint detection of 100 TCID50/ml, sensitivity of 92% (all specimen types) and specificity of 100%. The direct EIA sensitivity was 97% in non-genital specimens and 88% in genital specimens. The culture amplified EIA showed a sensitivity of 95% compared to all confirmed HSV positive samples.

CONCLUSIONS

The results of the HSV rapid tests were available within 24 h from receipt of specimens. Specimens which were culture negative/direct EIA positive were confirmed by blocking antisera. Culture positive specimens which were direct EIA negative were confirmed by subtyping of the virus.

A sensitive enzyme-linked immunosorbent assay for the detection of herpes simplex virus antigens

A sandwich ELISA for the detection of herpes simplex virus (HSV) antigens was developed using sheep anti-HSV F(ab')2 fragments for capture and an indirect antibody system for detection. Current detection limits are 0.5 ng protein for HSV1 and 1.5 ng protein for HSV2. This compares to a single HSV1-infected Vero-cell in a background of 10(6) non-infected cells or 10 plaque forming units (PFU) of HSV1 in culture supernatants as determined in separate experiments. Limiting dilution experiments show that one PFU of HSV1 can be detected after overnight culture in both supernatant and cell extracts. The use of F(ab')2 for capture completely eliminated binding of Staphylococcus aureus. No cross-reactivity was observed with other human herpes viruses. When evaluated with 245 random 'left-overs' of genital swab specimens in transport medium the test showed a sensitivity and specificity of 77.2 and 97.8%, respectively, with respect to virus isolation in culture. In a preliminary study on 16 direct ELISA swab-specimens extracted in 0.5 ml ELISA sample buffer both sensitivity and specificity were 100% with respect to culture. In both clinical series there was a proportional relationship between the ELISA value and the estimated amount of infectious virus in the specimen.

Typing of herpes simplex virus by capture biotin-streptavidin enzyme-linked immunosorbent assay and comparison with restriction endonuclease analysis and immunofluorescence method using monoclonal antibodies

A sensitive enzyme-linked immunosorbent capture assay using biotin and streptavidin (capture B/SA ELISA) was developed using type-specific monoclonal antibodies for typing of herpes simplex virus. Rabbit anti-herpes simplex virus immunoglobulin G was used as the capturing antibody, and biotin-linked type-1-specific mouse monoclonal antibody or rabbit type-1- or type-2-specific polyclonal antibody served as the detecting antibody. The captured antigen was detected by an ELISA with alkaline phosphatase-conjugated streptavidin, which reacted with biotin molecules on the detector antibody. The capture B/SA ELISA was compared with other methods for efficiency and reliability in typing. Results obtained by restriction endonuclease digestion of the radiolabeled viral genome were used to determine the type (1 or 2) of clinical isolates. These results were then used as a reference for determining the accuracy of the capture B/SA ELISA, as well as that of the immunofluorescence method, both of which are easily adaptable for use in the clinical laboratory. The three methods were in perfect agreement. It was determined that both the capture B/SA ELISA and the immunofluorescence method using monoclonal antibodies provided typing results with 100% specificity and 100% sensitivity and thus were accurate and reliable. However, the ELISA was the method of choice because of its simplicity, rapidity, and use of nonradioisotopic reagents.

Indirect immunofluorescent antibody diagnosis of herpes simplex with upper tarsal and corneal scrapings

Indirect immunofluorescent techniques were used to diagnose active herpes simplex virus ocular infections in 84 patient observations (41 with ocular lesions suspicious clinically for herpes simplex and 43 with lesions suspicious clinically for other ocular inflammatory conditions). We found indirect immunofluorescent antibody techniques to have a high sensitivity (97%) and specificity (73%) when compared to herpes simplex virus cultures. Similarly, we found the sensitivity (98%) and specificity (77%) of indirect immunofluorescent antibody techniques to be high when compared to the clinical diagnosis of herpes simplex viral infection. Significantly, there were no false negative tests by indirect immunofluorescent techniques. Both corneal and upper tarsal scrapings by indirect immunofluorescence were used and the upper tarsal scrapings were an excellent source of cells exhibiting herpes simplex virus antigens. All cases in which corneal scrapings were positive by indirect immunofluorescence for herpes simplex ere also positive by upper tarsal scrapings, although the converse was not true.

Laboratory diagnosis of herpes simplex virus infections. Principles guiding the development of rapid diagnostic tests

While the incidence of many bacterial sexually transmitted diseases appears to be decreasing, the complications and frequency of viral sexually transmitted diseases in developed countries has increased over 10-fold in the last decade. Since 1975 genital herpes simplex virus infections have increased at a rate of 12% in the United Kingdom. Significant advances in our understanding of the epidemiology, natural history, and therapy of symptomatic genital herpes has occurred in the last 5 yr. In order to properly utilize this information, however, more widespread availability of laboratory diagnostic testing for herpes simplex virus is needed. The availability of tissue culture isolation facilities for herpes simplex virus has expanded to many community hospitals. More importantly, rapid assays to detect herpes simplex virus using monoclonal and polyclonal antibodies in enzyme-linked immunosorbent assay and immunofluorescent assays and/or detection of herpes simplex virus deoxyribonucleic acid by hybridization methods have also been developed. Recent studies indicate that these assays approach the sensitivity of viral isolation when samples from mucocutaneous lesions are taken. These rapid assays have also allowed clinicians to more rapidly diagnose serious herpes simplex virus infection such as neonatal herpes and to institute antiviral therapy earlier in the course of disease. Although the specificity of these assays in high prevalence populations appears excellent, few studies have evaluated these assays in populations where the prevalence of herpes simplex virus is low. Rapid assays for herpes simplex virus also appear to have decreased sensitivity (less than 60%) in detecting asymptomatic excretion of herpes simplex virus from the lower genital tract.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme immunoassays for the detection of microbial antigens and prospects for improved assays

The rapid diagnosis of viral infections is an important tool in the management of patients with infectious diseases. Solid-phase enzyme immunoassays have proved to be useful tools for the direct detection of the antigens of some viruses directly in clinical specimens. Such assays have been particularly useful in the diagnosis of viral infections in the gastrointestinal and respiratory tracts. However, standard solid-phase enzyme immunoassays often do not display sufficient sensitivity for the diagnosis of all cases of viral infections. Techniques which might be utilized to increase the sensitivity of solid-phase immunoassays include the use of monoclonal antibodies to maximize the efficiency of the antigen-antibody interactions and the use of high-turnover enzymes to increase the amount of signal generated by the ensuing enzyme-substrate reactions. In addition, techniques making use of nucleic acid hybridization have a great deal of potential for the accurate detection of viral nucleic acids in human body fluids. The successful application of these techniques to the diagnosis of viral infections could lead to a marked improvement in the care of patients with suspected infectious diseases as well as to a decrease in the transmission of viral infections to high-risk individuals.