Enzyme immunoassay for measurement of antibodies to herpes simplex virus infection: comparison with complement fixation, immunofluorescent-antibody, and neutralization techniques

Herpes Simplex Virus and Human Cancer. III. Search for Relationship of Herpes Simplex Antibodies and Cervical Dysplasia and Labial Neoplasia

We employed the enzyme-linked immunosorbent assay (ELISA), indirect hemagglutination (IHA), and complement fixation (CF) methods to measure antibody titer to herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in patients affected by labial tumors or cervical dysplasias. No relationship of antibody titer to HSV-1 and labial tumors was detected by any of the three methods. Association between antibody titer to HSV-2 and cervical dysplasias was revealed by IHA (p < 0.05) and ELISA (p < 0.001); CF tests were negative. Moreover, we assayed for HSV-specific antigens in cell cultures derived from labial tumors and cervical dysplasias. In cultures from labial tumors, it was not possible to detect HSV-specific antigens. Of the 25 cultures derived from cervical dysplasias, HSV antigens were found in only 3 cultures.

Epidemiology of herpes simplex virus in children by detection of specific antibodies in saliva

OBJECTIVES

To facilitate the study of the prevalence of herpes simplex virus (HSV) infection and its determinants in children, we developed a noninvasive saliva test.

METHODS

A capture enzyme-linked immunosorbent assay (ELISA) for the detection of IgG to HSV in saliva was developed, validated against a commercial serum ELISA in 110 children and 187 adults and used in a cross-sectional population-based study including 2,048 children ages 1 to 17 years, recruited in day-care centers and schools of Geneva, Switzerland. Demographic and socioeconomic determinants of HSV prevalence were studied.

RESULTS

The sensitivity and specificity of the saliva assay were 94.1 and 95.5%, respectively, compared with the commercial serum ELISA. Participation in the cross-sectional study was 86.6%. The overall prevalence of anti-HSV IgG was 23.91%. It increased with age up to 7 years, reaching a plateau at 35% without evidence for day-care or school transmission. The main determinants of prevalence were region of national origin and parents' professional category.

CONCLUSIONS

This new saliva-based assay proved its feasibility in the first population-based study of HSV prevalence in children that uses saliva, confirmed its validity by identifying determinants of prevalence consistent with previous reports and yielded new information, such as the lack of influence of day-care attendance, in the population studied.

A novel method to assay herpes simplex virus neutralizing antibodies using BHKICP6LacZ-5 (ELVIS) cells

A novel method for determining neutralizing serum antibody titers to herpes simplex virus type 2 (HSV-2) was developed based on reduction of infectivity in BHKICP6LacZ-5 (ELVIS) cells; baby hamster kidney (BHK) cells that have been genetically engineered to contain the Escherichia coli LacZ gene under the control of an inducible herpes simplex virus type 1 (HSV-1) promoter. The test has a semiautomated, colorimetric readout resulting in rapid, objective readings of infectivity reduction. Extent of neutralization is calculated against a calibration curve of virus infectivity generated in each run. HSV-2 neutralizing activity can be detected with serum dilutions in excess of 1:5120.

Rapid diagnosis of ocular herpes simplex infections

BACKGROUND

The Surecell herpes (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 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.

Evaluation of 3 nonradioactive DNA detection systems for identification of herpes simplex DNA amplified from cerebrospinal fluid

The efficiencies of 4 different hybridization assays, using probes labeled with 32P, digoxigenin (DIG) and biotin, were compared for the detection of herpes simplex virus (HSV) DNA amplified from cerebrospinal fluid during herpes simplex encephalitis (HSE). The biotinylated probe was shown to provide a clearly lower sensitivity than the radioactive hybridization system, regardless of whether the biotin-labeled probe was detected by a colorimetric or by a photobiotin assay. In contrast, the DIG system, which includes a luminescent detection step was shown to be equivalent to the 32P system, at least at lower template concentrations. Although generally higher background signals were observed with the DIG assay the analysis of 73 CSF samples yielded identical results with the 32P and the DIG test systems in all cases, identifying concordantly an HSE in 6 patients. Since the time necessary for the performance of both assays is similar the DIG system seems to be a powerful alternative to the radioactive detection of amplified HSV DNA.

Evaluation of the polymerase chain reaction for diagnosis of herpes simplex virus encephalitis

Cerebrospinal fluid samples from 257 patients with suspected herpes simplex virus encephalitis were prospectively analyzed by herpes simplex virus polymerase chain reaction. The polymerase chain reaction indicated herpes simplex virus encephalitis in 9 serologically proven cases and in 14 additional patients. Increased polymerase chain reaction signals were observed together with more severe neurological symptoms (P < 0.01) and within the first days of acyclovir treatment (P < 0.05).

Indirect ELISA for the detection of HSV-2 specific IgG and IgM antibodies with glycoprotein G (gG-2)

The glycoprotein G (gG-2) purified from HSV-2 infected cells has been reported to be useful for determination of HSV-2 type-specific antibodies using conventional ELISA formats. This study further confirmed the specificity of gG-2 and demonstrated the feasibility of a specific IgM assay. The gG-2 ELISA was developed to detect HSV-2 specific IgG and IgM antibodies in human sera with high levels of sensitivity and specificity. Of 45 patients with culture-proven recurrent HSV-2 genital infection 44 were reactive for gG-2 IgG. Of 30 sera from patients with culture-proven recent initial HSV-2 genital infection 29 were positive for gG-2 IgM. Three patients with primary HSV-2 genital infection showed gG-2 IgM in the convalescent but not in the acute sera. The IgG- and IgM-gG-2 ELISA showed high specificity. None of 40 sera from children were reactive by either assay. Only one of 94 sera from patients with antibody to herpesviruses other than HSV reacted in the IgG assay but none reacted in the IgM assay. There was no cross-reaction with sera from patients with proven HSV-1 infection with the gG-2 antigen. The results suggest that the IgG assay can be used for demonstration of past HSV-2 infection and the IgM assay for the diagnosis of HSV-2 in neonatal herpes and primary genital herpes, when cultures or rapid diagnostic techniques are unavailable.

Establishment of PCR for the early diagnosis of herpes simplex encephalitis

The early detection of herpes simplex encephalitis (HSE) represents a major problem in viral diagnostics. We have now established a test system based on PCR for the specific amplification of HSV-DNA in cerebrospinal fluid (CSF) samples followed by oligonucleotide hybridization. The test proved to be very sensitive. Five molecules of HSV 1 DNA still yielded positive signals after hybridization. The assay was applied to CSF samples from 6 patients with confirmed HSE. All except one CSF sample obtained from the 2nd to the 8th day after onset of neurological symptoms yielded positive results. The primers used also exhibit a certain degree of crossreactivity with HSV 2, as revealed by testing of a CSF sample from an HSV 2-infected child. No positive signals were obtained with human DNA and with DNA from CMV- and VZV-infected fibroblasts. Also 42 CSF samples of patients suffering from other diseases of the CNS yielded negative results. The present results indicate that the detection of HSV DNA in CSF by PCR represents a valuable tool for the early diagnosis of HSE.

Development of an enzyme-linked immunosorbent assay for equine infectious anemia virus detection using recombinant Pr55gag

To provide more sensitive and convenient methods for the detection of equine infectious anemia virus (EIAV), we developed an enzyme-linked immunosorbent assay (ELISA) employing the EIAV gag precursor (Pr55gag) produced by using recombinant DNA techniques. The antigenic reactivity of the recombinant EIAV Pr55gag was found to be equivalent to that of the virion p24gag and elicited high-titered antiserum in rabbits. When a large number of horse sera were analyzed for the presence of antibodies to EIAV by this ELISA, a radioimmunoassay for EIAV p15gag, or the standard agar gel immunodiffusion test, there was 98.7% concordance among the assays. By using the ELISA it was possible to specifically detect antibodies earlier after experimental infection of horses with EIAV than with the other two tests. A competition ELISA developed in order to detect EIAV gag antigens was found to be approximately 15 times more sensitive than the radioimmunoassay for EIAV p15gag. Antigens of other animal lentiviruses as well as those of the prototype oncovirus failed to compete in this assay.

Comparison of a rapid latex agglutination assay and a fluorescent-antibody technique for the detection of herpes simplex antibody

A total of 202 serum specimens was tested for the presence of herpes simplex virus antibody using a premarket latex agglutination kit (Wampole) and an indirect fluorescent antibody (IFA) technique (electronucleonics). Discrepant results between the two assays were resolved using an Enzyme-linked immunosorbent assay (ELISA) procedure. The overall sensitivity of the latex was 99.2% with a specificity of 98.5%. The latex agglutination test evaluated is a viable alternative to indirect immunofluorescence for the detection of herpes simplex virus antibody in serum samples.

Rapid detection of herpes simplex virus (HSV) antigen in human ocular infections

The new HERPCHEK (Dupont, No. Billerica, MA) enzyme immunosorbent assay (EIA) was used in a double-blind clinical study for rapid and specific detection of ocular herpes simplex virus (HSV) infection. This 4-hour assay can be used to demonstrate conclusively the presence of HSV antigen without culture and thereby rapidly differentiate between HSV and other clinically similar ocular infectious diseases. Ocular samples were collected from 180 individuals including 30 patients with acute HSV, 90 with latent HSV (ie, currently asymptomatic but with a positive history), 11 with acute or latent varicella zoster virus, 30 with nonherpetic infections (due to adenovirus, Acanthamoeba or bacteria), and 19 normal controls. A clinical diagnosis was made by one of us (DPL) and duplicate tear-film samples obtained by swabbing the conjunctival cul-de-sac and cornea. Coded samples were tested by routine viral culture on Vero cell monolayers and also were run independently in the HERPCHEK test. During active HSV infection, the HERPCHEK correlated 100% with clinical diagnosis, and virus culture correlated 90% with clinical diagnosis. In all latent HSV ocular infections, other nonherpetic ocular infections and normal samples, both the HERPCHEK and culture assays were negative.

Development of an enzyme-linked immunosorbent assay for caprine arthritis-encephalitis virus

Because relatively few caprine arthritis-encephalitis virus (CAEV)-infected animals exhibit clinical signs of illness, efforts to control and eradicate this virus will depend heavily on a sensitive diagnostic test that can be easily carried out. The currently utilized tests are of limited usefulness because of relatively low sensitivity or because of incomplete cross-reactivity of goat sera with heterologous test antigens. An enzyme-linked immunosorbent assay (ELISA) with purified CAEV antigen and biotin-avidin amplification steps was therefore developed and compared with a radioimmunoassay (RIA) against CAEV p28. Of over 500 sera tested, there was 99% concordance between the two tests. On the other hand, 23 of 24 sera obtained from animals with clinical signs of disease that were negative by agar gel immunodiffusion test (with ovine progressive pneumonia virus antigen) were positive by ELISA and RIA. These results suggest that an ELISA with CAEV antigen is superior to the agar gel immunodiffusion test and is easier and faster than an RIA, and therefore may be the method of choice for diagnosing CAEV infection.

Vestibular neuronitis--serum and CSF virus antibody titer

The cerebrospinal fluid (CSF) findings of patients with vestibular neuronitis were virologically evaluated and discussed in contrast to those of herpes zoster. CSF samples obtained from seven patients with vestibular neuronitis, aged 28 to 55 years, were examined. The results were as follows: The CSF protein level in the vestibular neuronitis showed the peculiar change; i.e. its level was normal at the onset period of vertigo, but it rose to abnormal levels mostly in the period of two weeks, while the cell count remained normal throughout all phases of our study. Herpes simplex virus (HSV) type 1 IgG antibody titers measured by indirect immunofluorescent antibody technique (IF) in paired sera rose in one of the seven cases of vestibular neuronitis, but the antibody titers of the same virus in the CSF were not detected. HSV type 1 IgG antibody titers measured by IF in the CSF were detected in two of seven cases of vestibular neuronitis, but not significant. The ratio of EB virus (EBV) capsid antigen IgG antibody titers in CSF to that in serum ranged from 1:160 to 1:80 in vestibular neuronitis. There was no direct available evidence that vestibular neuronitis caused a break in blood-CSF barrier, an increase in IgG synthesis in the central nervous system or active infection with HSV, varicella zoster virus (VZV), or EBV. In this paper, we summarized the recent information on studies of the CSF and a latent herpes virus infection in order to give perspective to the pathogenesis of vestibular neuronitis.

Use of enzyme-labeled antigen for the detection of immunoglobulin M and A antibody to herpes simplex virus in serum and cerebrospinal fluid

A direct enzyme-linked immunosorbent assay (ELISA that used peroxidase-labeled antigen) was developed for detection of IgM and IgA antibody to herpes simplex virus (HSV). The assay uses immuno-affinity-purified antihuman IgM or IgA antibody-coated wells of microtiter plates to separate IgM or IgA from other classes of antibody in serum or cerebrospinal fluid (CSF). The presence of specific IgM or IgA is detected by subsequent, consecutive incubation with peroxidase-labeled antigen and substrate. HSV antigen was purified by sucrose gradient centrifugation and coupled with peroxidase by the periodate method. By examining sucrose-gradient-fractionated sera the assays were shown to be specific for IgM and IgA classes of antibody. None of the sera from patients with Epstein-Barr virus (n = 20), cytomegalovirus (n = 20), or varicella-zoster virus (n = 8) infection or with both rheumatoid factor and IgG antibody to HSV (n = 13) reacted positively. Only one out of 78 sera from healthy persons was positive for IgA antibody to HSV, and none for IgM antibody. All 33 patients with HSV infection developed HSV-IgA, 22 developed HSV-IgM. Of the 11 patients with primary infection, all had IgM antibody in their first sera and six had IgA antibody. The corresponding figures for the 22 patients with recurrent infection were five and nine. Furthermore, HSV-IgA antibody was found in serum and CSF of all five patients with HSV encephalitis in the second week after onset of symptoms, indicating the usefulness of the assay as a noninvasive technique for diagnosing HSV encephalitis.

A single dilution enzyme-linked immunosorbent assay for the quantitative detection of antibodies to bovine herpesvirus type 1

Three serological assays were compared for detection of antibodies to bovine herpes-virus type 1. These were virus neutralization (VN), enhanced complement fixation (CF) and enzyme-linked immunosorbent assay (ELISA). The ELISA was developed using an infected cell lysate antigen and purified virus and was optimized in relation to antigen and antisera dilutions. The CF assay was enhanced by the addition of bovine complement. These 3 assays were compared for detection of: specific virus antibody titers; sero-conversions; early antibody response in experimentally-infected cattle. Both ELISA end-point titers and single dilution values were found to be more sensitive than the CF or VN assays for specific antibody level quantitation. With a single dilution ELISA test procedure a correlation was obtained between ELISA values and VN titers. Using the single dilution ELISA test the assay also detected antibodies in experimentally-infected cattle before either the VN or CF assays, and agreed with the VN test in 35/38 seroconversions found by 4-fold or more VN changes between acute and convalescent paired sera from naturally-infected animals. The single dilution ELISA was a rapid and sensitive test for routine antibody detection in bovine sera.

Determination of herpes simplex virus type-specific antibodies by enzyme-linked immunosorbent assay

We determined type-specific antibodies to herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) by an indirect enzyme-linked immunosorbent assay, using as antigens HSV-1 glycoprotein gC-1 and a HSV-2-specific polypeptide purified on affinity columns of monoclonal antibodies. All sera were initially screened for HSV antibodies by the enzyme-linked immunosorbent assay with a pool of Triton X-100-extracted antigens of HSV-1- and HSV-2-infected HEp-2 cells. The titer of HSV antibodies was predicted from a linear regression curve based on the absorbance of the initial 1:50 serum dilution. The sensitivity and specificity of the screening assay and of the assay for type-specific antibodies were established.

An ELISA technique to detect IgG antibody to the early herpes simplex virus type 2 (HSV-2) antigen AG-4 in HSV-2 patients

An ELISA system, based on urease activity was used for the detection and titration of IgG to the immediate early AG-4 antigen in sera from HSV-2 patients. It detected low levels of IgG to the AG-4 antigen in 32% of patients' sera known to contain complement fixing antibody to the antigen. Furthermore, the sensitivity of the ELISA system was 2- to 10-fold higher than the complement-fixation system depending on when the sera was taken from the HSV-2 patients. The system also allowed the easy detection and quantitation of AG-4 antigen production when various HSV-1 X HSV-2 intertypic recombinant viruses were used to infect BHK-21 cells.

Evaluation of a computer-assisted, kinetics-based enzyme-linked immunosorbent assay for detection of coronavirus antibodies in cats

A computer-assisted, kinetics-based enzyme-linked immunosorbent assay was adapted for the detection of coronavirus antibodies in feline serum. An alkaline antigen diluent (carbonate-bicarbonate buffer, pH 9.6) used in initial experiments produced diffuse, nonspecific color reactions in both viral and control antigen cuvettes which were correlated, paradoxically, with coronavirus antibody levels in test sera. These interfering reactions were minimized by use of lower-pH antigen diluents such as water and phosphate-buffered saline. Background kinetics-based enzyme-linked immunosorbent assay reactivity directed against a noncoronaviral component of antigen tissue culture fluids could then detected in numerous sera, particularly in samples with lower titers. Much of this reactivity was shown to be associated with bovine gamma globulins in cell culture fluid. It was not serum lot or species specific, since a variety of bovine serum lots as well as individual lots of serum from other mammalian and avian species reacted. Reactivity was markedly reduced when cells for antigen preparation were grown in gamma globulin-free bovine serum. Generation of corrected slope values from the kinetics-based enzyme-linked immunosorbent assay made it possible to correct for residual background reactivity in individual test sera and thus eliminate a potentially major source of false-positive reactions. Collectively, these studies indicated that the control of nonspecific reactivity in feline coronavirus serology is absolutely essential to obtain useful estimates of specific antibody responses.

Enzyme-linked immunosorbent assay (ELISA) for detection of herpes simplex virus-specific IgM antibodies

Herpes simplex virus (HSV)-specific IgM in human serum could be detected by a microplate enzyme-linked immunosorbent assay, using extracts of HSV-infected cells as antigen. Peroxidase-conjugated anti-human IgM was used to detect human IgM bound to viral antigen. Pretreatment of sera with protein A-bearing staphylococcus or with aggregated human IgG was necessary to eliminate false-positive results caused by the presence of rheumatoid factor. Specificity controls included sera of patients with other herpes group virus infections.

Freeze-dried erythrocytes for an indirect hemagglutination test for detection of cytomegalovirus antibodies

An indirect hemagglutination test with lyophilized, fixed, tanned, and cytomegalovirus (CMV)-sensitized sheep erythrocytes for the detection of CMV antibodies is reported. To avoid nonspecific hemagglutination, cells were fixed with glutaraldehyde or Formalin directly in whole blood. The lyophilized, CMV-sensitized erythrocytes obtained by this technique were stable up to 9 months at 37 degrees C and retained the same reactivity at fresh, CMV-sensitized cells. Indirect hemagglutination performed with lyophilized, sensitized cells was highly efficient in detecting CMV-antibodies as compared with complement fixation and enzyme immunoassay.

Prevalence of herpes simplex virus disease in a professional population

By virtue of occupation, dentists are frequently exposed to the herpes simplex virus. The risk of infection by the virus was evaluated by assessing disease experience as shown by history compared with the results of complement fixing or antibody titration tests, or both.

Correlation of herpes simplex virus antibody titers and specific lymphocyte stimulation in adult blood donors

Antibody titers to herpes simplex virus type 1 in sera from healthy adult donors were assayed by complement fixation, microneutralization, and an enzyme immunoassay (ELISA). This last test proved to be the most sensitive method for antibody detection. It was estimated that ELISA antibody titers were up to 40-fold higher than neutralizing antibody titers and up to 100-fold higher than complement fixation antibody titers. Due to the higher sensitivity of ELISA, only 3 of 36 blood donors tested in this assay were shown to be seronegative, whereas 6 additional persons of the same group were termed seronegative by the microneutralization assay. Furthermore, four of the latter also did not respond in the complement fixation test. In vitro stimulation of peripheral lymphocytes by using a partially purified herpes simplex virus type 1 particle antigen was achieved for all seropositive blood donors. Only those three donors who were ELISA negative reacted negatively in this stimulation assay. From these results it may be concluded that ELISA is an appropriate method not only for rapid and sensitive antibody determination but also for selecting herpes simplex virus-negative patients.