Secreted portion of glycoprotein g of herpes simplex virus type 2 is a novel antigen for type-discriminating serology

The secreted portion of glycoprotein G (sgG-2) of herpes simplex virus type 2 (HSV-2) was evaluated as a novel antigen in an enzyme-linked immunosorbent assay (ELISA) format for detection of type-specific immunoglobulin G (IgG) antibodies in HSV-2-infected patients. The results were compared with those obtained by a commercially available assay, the HerpeSelect 2 ELISA (the FOCUS2 assay). Five different panels of sera were analyzed: panel A consisted of 109 serum samples from patients with a culture-proven HSV-1 infection that were Western blotting (WB) negative for HSV-2; panel B consisted of 106 serum samples from patients with a culture-proven recurrent HSV-2 infection that were WB positive for HSV-2; panel C consisted of 100 serum samples with no detectable IgG antibodies against HSV-1 and HSV-2; panel D consisted of 70 HSV-2 negative "tricky" serum samples containing antinuclear IgG antibodies or IgM antibodies against other viruses or bacteria; and panel E consisted of consecutive serum samples from 21 patients presenting with a first episode of HSV-2-induced lesions. When sera in panels A to C were analyzed, the sgG-2 ELISA and the FOCUS2 assay both showed sensitivities and specificities of >or=98%. In total, among the samples in panel D, 13 serum samples (19%) were false positive by the FOCUS2 assay and 1 serum sample (1.4%) was false positive by the sgG-2 ELISA. When the sera in panel E were analyzed, the sgG-2 ELISA detected seroconversion somewhat later than WB or the FOCUS2 assay did. We conclude that sgG-2 induces an HSV-2 type-specific antibody response and can be used for type-discriminating serology.     

Seroprevalence of herpes simplex virus type 1 and type 2 in selected German populations-relevance for the incidence of genital herpes

This study was carried out to determine the prevalence of antibodies to herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) in selected German populations, such as blood donors, hospital patients, and human immunodeficiency virus (HIV)-seropositive individuals. Serum samples collected between 1996 and 1998 were tested by enzyme immunoassays using monoclonal antibody-selected native gG1 and gG2 as antigens and an immunoblot using type-specific recombinant glycoproteins. Equivocal results were resolved by an "in-house" Western blot assay. The prevalence of HSV-1 antibodies increased steadily with age and reached high levels of >/=88% among subjects 40 years of age or older. In the sample of patients and blood donors, the HSV-2 seroprevalence was 12.8% (95% CI = 11.9-13.8%). About 81% of the HSV-2 seropositive subjects were coinfected with HSV-1. When adjusted for age, there was no difference in the HSV-2 seroprevalence between hospital patients and blood donors. The HSV-2 seroprevalence was significantly higher among women (15%) than among men (10.5%), yielding a female : male odds ratio of 1.5 for hospital patients and of 1.67 for blood donors. Among the HIV-infected population, 91.1% were seropositive for HSV-1 and 47.9% for HSV-2. HIV-infected women have a significantly higher risk of HSV-2 infection than men (odds ratio [OR] = 3.22; 95% confidence ratio [CI] 1.99-5.20). In conclusion, although the rate of infections with HSV-2 is relatively low in the German population, attention should be given to the further development in adolescents, especially in view of a possible decrease of HSV-1 seroprevalence in childhood.     

Seroprevalence of HSV-1 and HSV-2 in Barbados

Type-specific enzyme-linked immunosorbent assays, based upon recombinant glycoprotein G (gG), were used to detect antibodies to HSV-1 and HSV-2, in a small Caribbean island population. A blinded serosurvey was performed on samples from 184 blood donors, 122 pregnant women, and 120 HIV-positive patients. The seroprevalence of HSV-1 and HSV-2 was 81% and 34%, respectively, in blood donors, 84% and 40% in the antenatal population and 89% and 77% in the HIV-positive group. As expected the majority of adults were seropositive against HSV-1. However, the HSV-2 seroprevalence was significantly higher in HIV-infected adults than in the other groups. These findings support the need for prospective epidemiological studies in this population.     

Whole cell lysate enzyme immunoassays vs. recombinant glycoprotein G2-based immunoassays for HSV-2 seroprevalence studies.

Seroepidemiology studies of herpes simplex virus type 2 (HSV-2) infections have been difficult to carry out because antibodies to HSV type 1 (HSV-1) show an extensive cross-reactivity with HSV-2 antigens. Many kits available currently are not entirely type specific for serodiagnosis of HSV-2 infections and therefore do not allow reliable discrimination of past exposure to these closely related alphaherpes viruses. Attempts to develop type-specific antigens have focused on the envelope glycoproteins, particularly glycoprotein G (gG). A cross-sectional study was carried out to examine the seroprevalence of antibodies to HSV-2 among healthy university students, using different methods: a whole cell lysate enzyme-linked immunosorbent assay (ELISA), two different ELISAs, and a newly developed immunoblot assay, the last three based on recombinant gG2. HSV-2 prevalence was 24 times higher with the whole cell lysate ELISA (31%; 95% confidence interval [CI]: 27-35%) than the ELISAs and the immunoblot assay based on recombinant gG2 (1.3%; 95% CI: 0.1-2.5%), thus showing the inaccuracy of commercial tests based on whole-antigen preparations for epidemiological studies. Laboratories should be cautious and ensure that commercial tests for HSV typing are based on type-specific glycoproteins.     

Detection of herpes simplex virus type-specific antibodies by an enzyme-linked immunosorbent assay based on glycoprotein G

In order to develop a simple and quantitative method to detect herpes simplex virus (HSV) type-specific antibodies, the usefulness of an enzyme-linked immunosorbent assay (ELISA) using HSV glycoprotein G (gG) captured on a plate by monoclonal antibodies as antigen was studied. The gG1- and gG2-specific IgG antibody activities were measured by the ELISA for 54 sera which had been collected from culture-proven genital herpes patients and pre-characterized by an immunodot assay using purified gG antigens. Thirty control sera without antibodies against the HSV whole antigens were also included. In comparison with the immunodot assay as standard, the sensitivities of the ELISA were 88.9% (32/36) for HSV-1 antibody and 89.2% (33/37) for HSV-2 antibody and the specificities were both 100%. Sera taken within a few months after primary infection tended to give false negative results. The HSV type-specific ELISA based on easy-to-prepare gG antigens might be useful to help improve the serological assessment of HSV infections. J. Med. Virol. 53:319–323, 1997. © 1997 Wiley-Liss, Inc.     

Seroprevalence and determinants of herpes simplex type 2 infection in an STD clinic in Milan,Italy

A number of studies have shown that the seroprevalence of herpes simplex virus type 2 (HSV-2) is higher among persons attending clinics for sexually transmitted diseases (STD) than among the general population. The HSV-2 seroprevalence among STD patients, however, varies greatly among studies, possibly reflecting differences in the baseline prevalence of the infection among different general populations or in the distribution of risk factors. A cross-sectional study was carried out to determine the seroprevalence of and the risk factors for HSV-2 infection among 776 HIV-negative persons attending an STD clinic in Milan, Italy. All samples were tested with a commercial HSV type-2 specific gG ELISA test. The HSV-2 seroprevalence was 29.5% (95% CI: 26.3-32.7%). The seroprevalence increased with age, yet it did not differ by gender. Among persons with a current STD, the seroprevalence was 44.3%. At the multivariate analysis, older age was independently associated with HSV-2 infection. A self-reported history of genital herpes was predictive of HSV-2 infection. The agreement between history of genital herpes and HSV-2 seroprevalence was poor, however, stressing that in clinical practice, caution should be used in interpreting the presence or absence of a history of genital herpes as an indicator of the presence or absence of HSV-2 infection. Our data show that HSV-2 seroprevalence among persons attending an STD clinic in Italy is high; thus serological screening for HSV-2 might be advisable for STD patients.     

Production of herpes B virus recombinant glycoproteins and evaluation of their diagnostic potential

B virus (cercopithecine herpesvirus 1) is the only deadly alphaherpesvirus that is zoonotically transmissible from macaques to humans. The detection of humoral immune responses is the method of choice for the rapid identification of B virus-infected animals. We evaluated the diagnostic potential of recombinant B virus glycoproteins for the detection of immunoglobulin G (IgG) antibodies in monkey and human sera. Glycoproteins B, C, and E and secreted (sgG) and membrane-associated (mgG) segments of glycoprotein G (gG) were expressed in the baculovirus expression system, while gD was expressed in CHO cells. We developed recombinant protein-based IgG enzyme-linked immunosorbent assays (ELISAs) and compared their diagnostic efficacies by using B virus antibody-negative (n = 40) and -positive (n = 75) macaque sera identified by a whole antigen-based ELISA and Western blotting. The diagnostic sensitivities of the gB-, gC-, gD-, and mgG-ELISAs were 100, 97.3, 88.0, and 80.0%, respectively. The specificities of the gB-, gC-, and gD-ELISAs and of the mgG-ELISA were 100 and 97.5%, respectively. In contrast, the sensitivities and specificities of sgG- and gE-ELISAs were low, suggesting that sgG and gE are less effective diagnostic antigens. Sera from nonmacaque monkeys cross-reacted with gB, gC, and gD, and only baboon sera reacted weakly with mgG. Human herpes simplex virus type 1 (HSV-1)- and HSV-2-positive sera pools reacted with gB and gD, whereas sera from B virus-infected individuals reacted with all four antigens. These data indicate that gB, gC, gD, and mgG have a high diagnostic potential for B virus serodiagnosis in macaques, whereas mgG may be a valuable antigen for discrimination between antibodies induced by B virus and those induced by other, closely related alphaherpesviruses, including HSV-1 and -2.     

Detection of HSV-2 in genital ulcers from STD patients in Dar es Salaam, Tanzania.

BACKGROUND: Genital ulcer disease (GUD) is common in many developing countries. Several reports indicate that there is an association with HIV infection. Analysis by polymerase chain reaction (PCR) has demonstrated that the ulcers are frequently caused by herpes simplex type 2 (HSV-2), although HSV-1 is becoming increasingly important in many parts of the world. Comparable studies have not been performed in Tanzania. OBJECTIVES: To determine the prevalence of HSV-2 and HSV-1 in genital ulcers in Dar es Salaam, Tanzania and determine their possible association with HIV infection. Study design: Samples were collected from 70 consecutive patients with GUD attending a clinic for sexually transmitted diseases. Specimens from ulcers were analysed by PCR for the presence of HSV-2 and HSV-1, and sera were examined for antibodies against HSV-2 and HIV. RESULTS AND DISCUSSION: HSV-2 DNA was detected in 64% of the specimens from ulcers while HSV-1 DNA was not found in any of them. Antibodies to HSV-2 and HIV were detected in 79.7 and 42% of the patients' sera, respectively. Although there was a significant positive association between HIV and HSV-2 seropositivity, HSV-2 DNA in genital ulcers was not more prevalent among HIV seropositive than among HIV seronegative individuals. CONCLUSION: The prevalence of HSV-2 antibodies among Tanzanian patients with genital ulcers is very high, and HSV-2 is detected in most of the ulcers. There is an association between infections with HIV and HSV-2, but the relationship is not clear.     

Seroprevalence of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in former East and West Germany, 1997–1998

The aim of this study was to investigate the seroprevalence of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in representative samples of the total former East German (FEG) and total former West German (FWG) populations. Type-specific testing with the HSV-1 (gG1) and HSV-2 (gG2) indirect ELISA was performed on an age- and sex-stratified random subsample of 3,792 sera collected during the 1997–1998 German National Health Survey. Weighted seroprevalence estimates were calculated for the total FEG and FWG populations. The overall age-standardised seroprevalence of HSV-1 was 82.6% in Germany, 85.5% (95%CI, 83.4–87.3%) in FEG and 81.8% (95%CI, 79.9–83.6%) in FWG. The overall seroprevalence of HSV-2 was 13.3% (95%CI, 11.8–14.9) in Germany, 16.5% (95%CI, 14.1–18.9) in FEG and 12.6% (95%CI, 10.7–14.5%) in FWG. The difference between FEG and FWG was largely due to the significantly higher age-adjusted seroprevalence of HSV-1 and HSV-2 in women (but not men) in FEG as compared to FWG. The HSV seroprevalence estimates in this study are consistent with results of previous less representative seroprevalence studies in Germany. Differences in HSV-2 seroprevalence between FEG and FWG suggest differences in sexual behaviour that warrant further investigation.     

Prevalence of, and risk factors for Kaposi's sarcoma-associated herpesvirus infection among blood donors in Brazil: a multi-center serosurvey

Kaposi's sarcoma-associated herpesvirus (KSHV) is endemic in the Amazon and rare in southern regions of Brazil. However, geographical distribution and epidemiological correlates of infection in this large country are still poorly defined. To estimate the seroprevalence of, and risk factors for, KSHV infection in Brazil, a multi-center study was conducted among 3,493 first-time voluntary unpaid blood donors from Salvador, Sao Paulo and Manaus. Antibodies against KSHV were detected using a whole-virus ELISA validated prior to the serosurvey. Antibodies against the latency-associated nuclear antigen (LANA) were detected by immuno-fluorescence assay (IFA) among ELISA-positive sera and a random sample of ELISA-negative sera. Overall, seroprevalence of KSHV by whole-virus ELISA was 21.7% (95% confidence interval (CI): 20-23.4%) in men and 31.7% (95% CI: 29-34.3%) in women (P<0.0001). KSHV antibodies were detected by IFA-LANA in 3% (95% CI: 2-4.3%) of 867 ELISA-positive samples and in none of 365 randomly selected ELISA-negative samples. In multivariate analysis, KSHV seroprevalence by whole-virus ELISA was independently associated with female sex (odds ratio [OR]=1.6, 95% CI: 1.4-1.9); residence in the Amazon (OR=1.4, 95% CI: 1.2-1.8; compared to Salvador); Caucasian ethnicity (OR=1.3, 95% CI: 1.1-1.6) and herpes simplex virus type 2 (HSV-2) infection (OR=1.3, 95% CI: 1.1-1.6). KSHV seroprevalence did not significantly increase with age, nor was it associated with self-reported sexual behavior. KSHV seroprevalence is high among Brazilian blood donors, particularly from the Amazon region. This study supports the co-existence of sexual and non-sexual routes of KSHV transmission in this population.     

Intratypic variation of herpes simplex virus type 2 isolates detected by monoclonal antibodies against viral glycoproteins

Monoclonal antibodies (MAbs) to herpes simplex virus (HSV) glycoproteins gD, gG, gB, and gE were used to analyze antigenic variations of 128 genital HSV-2 isolates by an indirect enzyme-linked immunosorbent assay (ELISA). Isolates were considered significantly different from the standard HSV-2 strain 186 when their optical density (OD) in ELISA was less than half that of strain 186. This criterion gave 30 patterns of reactivity among the genital HSV-2 isolates. The MAbs to gB, gG, and 2 of the gD antibodies reacted with more than 90% of the isolates, suggesting that these MAbs recognized highly conserved epitopes. However, the gE MAb reacted with only 47% of the isolates, and one of the gD antibodies with only 39%. Thus, HSV-2 can readily tolerate modifications in some parts of the gD and gE molecules while remaining infectious.     

Discrimination of antibody to herpes B virus from antibody to herpes simplex virus types 1 and 2 in human and macaque sera

The antigenic cross-reactive characteristics of herpes B virus and herpes simplex virus (HSV) type 1 (HSV-1) and HSV-2 are responsible for false-positive diagnoses by serological assays in humans and macaques. In the present study, we developed a fluorometric indirect enzyme-linked immunosorbent assay (ELISA) with recombinant herpes B virus glycoprotein D (gD) and HSV-1 and HSV-2 gG (gG-1 and gG-2, respectively) to discriminate between the three primate herpesvirus infections. The secreted form of gD, gDdTM, was used to detect antibody to herpes B virus gD. Sera positive for herpes B virus, HSV-1, and HSV-2 showed specific reactions to gD, gG-1, and gG-2, respectively. Sera collected from humans and rhesus macaques were investigated for the presence of antibodies to the recombinant proteins of the three herpesviruses. The results suggested that the approach is able to discriminate between herpes B virus and HSV infections. The ELISA was also found to be able to detect infections with multiple primate herpesviruses and may have the potential to identify a subsequent infection in individuals that have already been infected with another herpesvirus. In addition, we found evidence of a greater cross-reactivity of herpes B virus with HSV-1 than with HSV-2. It is suggested that the ELISA with the recombinant antigens is useful not only for the serodiagnosis of primate herpesvirus infections but also for elucidation of the seroprevalence of herpesviruses in humans and primates.     

Peptide based enzyme-linked immunoassays for detection of anti-HSV-2 IgG in human sera

Glycoprotein G of HSV-2 (gG2) and a peptide, corresponding to a previously recognised immunodominant epitope spanning residues 561-578 of the protein, were compared directly for type-specific serodiagnosis of HSV-2. The protein was affinity purified and obtained in a commercially available EIA kit while the peptide, previously designated as peptide 55, was made as a multiple antigenic peptide. A panel of 100 characterised serum samples (60 HSV-2 positive, 20 HSV-1 positive and 20 HSV negative) was screened using the two antigens. The intact protein and peptide 55 showed the same sensitivity for antibodies in the serum of HSV-2 infected individuals, reacting with 96.7% (58/60) of the samples. The peptide did not react with any of the HSV-1 positive or HSV negative sera. In contrast, gG2 gave a number of false positive results, reacting with 20% (4/20) of the HSV-1 positive sera and 10% (2/20) of the HSV negative sera. The superior performance of peptide 55, together with the very much lower costs of its production, compared with gG2 suggest that the peptide will become the antigen of choice in enzyme immunoassays for type-specific serodiagnosis of HSV-2.     

Enzyme-linked immunosorbent assay for determination of antibodies against herpes simplex virus types 1 and 2 in human sera.

A rapid and reproducible enzyme-linked immunosorbent assay (ELISA) is described for determining antibodies in human sera against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). The sera were absorbed for 30 min with heterologous virus-infected-cell extracts to remove cross-reacting antibodies and then were applied to ELISA plates containing the target antigens, immunoaffinity-purified HSV-1 glycoproteins gC and gD and HSV-2 glycoproteins gD and gF. The absorbance index, defined as the ratio of A414 generated by a serum sample absorbed with a heterologous virus-infected-cell extract versus the A414 of a serum sample absorbed with an uninfected-cell extract, was used to determine the presence or absence of antibodies to HSV-1 and HSV-2. Results of the ELISA for detecting antibodies against HSV-2, when compared with results obtained for the same sera by the microneutralization test, showed an index of overall agreement of 91%. Results of the ELISA for detecting antibodies against HSV-1, when compared with microneutralization test results for sera negative for HSV-2 antibodies but positive for HSV antibodies by ELISA, showed an index of agreement of 99%.     

Performance of Two Commercial Glycoprotein G-Based Enzyme Immunoassays for Detecting Antibodies to Herpes Simplex Viruses 1 and 2 in Children and Young Adolescents

In 61 patients 1 to 14 years of age, the Gull/Meridian enzyme-linked immunosorbent assay (ELISA) had a sensitivity of 100% for herpes simplex virus type 1 (HSV-1) and specificities of 74% for HSV-1 and 48% for HSV-2. In 128 similarly aged patients, the HerpeSelect ELISA (Focus Technologies) showed sensitivities of 80% for HSV-1 and 88% for HSV-2, and specificities of 97% for HSV-1 and 100% for HSV-2.     

Performance of two commercial glycoprotein G-based enzyme immunoassays for detecting antibodies to herpes simplex viruses 1 and 2 in children and young adolescents

In 61 patients 1 to 14 years of age, the Gull/Meridian enzyme-linked immunosorbent assay (ELISA) had a sensitivity of 100% for herpes simplex virus type 1 (HSV-1) and specificities of 74% for HSV-1 and 48% for HSV-2. In 128 similarly aged patients, the HerpeSelect ELISA (Focus Technologies) showed sensitivities of 80% for HSV-1 and 88% for HSV-2, and specificities of 97% for HSV-1 and 100% for HSV-2.     

Identification of an immunodominant sequential epitope in glycoprotein G of herpes simplex virus type 2 that is useful for serotype-specific diagnosis

A series of 67 oligopeptides that spanned the open reading frame of herpes simplex virus type 2 (HSV-2) glycoprotein G (gG2) were synthesized and tested for reactivity with 173 serum specimens collected from 117 individuals. The oligopeptides were made as multiple antigenic peptides consisting of four copies of a unique sequence attached to a branched lysine core and separated from the core by four glycine residues. The sera included HSV antibody-negative samples as well as sera from individuals from whom HSV had been isolated. Isolated viruses were typed by indirect fluorescence using a panel of type-specific monoclonal antibodies. One peptide, corresponding to residues 561 to 578 of gG2, did not react with any sera lacking HSV-specific antibodies or with sera from HSV-1-infected individuals, but did react with sera from HSV-2-infected individuals. For sera taken seven or more days after initialclinical lesions, the detection rate of the peptide was 92% (47/51), comparable with the 98% (50/51) of truncated glycoprotein D, a sensitive type-common reagent. We conclude that this peptide, of structure (PEEFEGAGDGEPPEDDDSG₄)K₃A, is an immunodominant type-specific epitope for human antibodies and should be useful for type-specific serodiagnosis of HSV-2. Surprisingly, the epitope lies within one of the most conserved regions of gG1 and gG2. The test can distinguish an initial HSV-2 infection in the presence of a preexisting HSV-1 infection. J. Med. Virol. 56:79–84, 1998. © 1998 Wiley-Liss, Inc.     

Conservation of type-specific B-cell epitopes of glycoprotein G in clinical herpes simplex virus type 2 isolates

Glycoprotein G (gG-2) of herpes simplex virus type 2 (HSV-2) is cleaved to a secreted amino-terminal portion and to a cell-associated, heavily O-glycosylated carboxy-terminal portion that constitutes the mature gG-2 (mgG-2). The mgG-2 protein is commonly used as a type-specific antigen in the serodiagnosis of HSV-2 infection. As the amino acid sequence variability of mgG-2 in clinical isolates may affect the performance of such assays, the gG-2 gene was sequenced from 15 clinical HSV-2 isolates. Few mutations were identified, and these were mostly localized outside the epitope regions described earlier. Five isolates were identical to different laboratory strains, indicating that the gG-2 gene is highly conserved over time. In the search for HSV-2 isolates harboring mutations within the immunodominant region of mgG-2, a pool of 2,400 clinical HSV-2 isolates was tested for reactivity with two anti-mgG-2 monoclonal antibodies (MAbs). Ten MAb escape HSV-2 mutants, which all harbored structurally restricted single- or dual-point mutations within the respective epitopes explaining the loss of binding, were identified. Sera from corresponding patients were reactive to mgG-2, as well as to a peptide representing the immunodominant region, suggesting that the point mutations detected did not diminish seroreactivity to mgG-2. The conservation of the gG-2 gene reported here further supports the use of mgG-2 as a type-specific antigen in the diagnosis of HSV-2 infections.     

Seroprevalence of herpes simplex virus types 1 and 2 in HIV-infected and uninfected homosexual men in a primary care setting.

BACKGROUND: Genital herpes is usually caused by herpes simplex virus type 2 (HSV-2), with infections often being unrecognised by patients and/or clinicians. HSV-2 infections may be a risk factor for the transmission of human immunodeficiency virus (HIV) infection. Reliable tests for type-specific HSV antibodies are now readily available. OBJECTIVES: To determine the seroprevalence of HSV-1 and -2 in HIV-seronegative gay men in a primary care setting in Melbourne, Australia, and to compare it with the rate in HIV-infected gay men. To assess the utility in a clinical setting of a type-specific HSV enzyme linked immunosorbent assay (ELISA) as compared with western blot. STUDY DESIGN: We recruited a total of 300 HIV-seronegative homosexual men attending for HIV antibody testing, and HIV-infected men attending for CD4 lymphocyte count and viral load estimation. The subjects completed a questionnaire, and sera were sent for total IgG HSV testing and testing by Gull type-specific HSV ELISA assay. Selected serum samples were retested by western blotting and the results analysed. RESULTS: In total, 168 HIV-antibody negative men and 132 HIV-antibody positive men were recruited. Of all subjects, 73.3% had HSV-1 antibodies. This proportion did not differ between HIV-seronegative and seropositive men (P=0.48). About twenty percent of HIV-seronegative men and 61% of HIV-seropositive men had antibodies to HSV-2 (P<0.0001); 75.6% of HIV-seronegative men with antibodies to HSV-2 gave no history of genital herpes, as did 66.7% of HIV-seropositive men. Overall, in using the type-specific ELISA (Gull) assay, false negative, false positive or equivocal results were obtained in 33/300 (11%) of samples tested compared with western blot. CONCLUSIONS: High rates of HSV-2 infection were found in homosexual males, with the rate for HIV-seropositive men being over twice that for HIV uninfected men. Most subjects were not aware of their infection with HSV-2. HIV-infected individuals were also older and had higher numbers of sexual partners, but we were unable to unambiguously establish that these variables contributed to the difference in HSV-2 seroprevalence rates. The Gull type-specific assay for HSV antibodies has significant problems with sensitivity and specificity at a discrepancy rate of 11%. Caution is advised in using this type-specific commercial assay for clinical purposes.     

Evaluation of confirmatory strategies for detection of type-specific antibodies against herpes simplex virus type 2

In this study, the optimal combination of three commercial glycoprotein G-2 (gG-2)-based herpes simplex virus type 2 (HSV-2) type-specific enzyme-linked immunosorbent assays (Euroimmun anti-HSV-2 immunoglobulin G [IgG] ELISA [Eu2], Gull HSV-2-specific IgG ELISA [Gu2], and Radim HSV-2 IgG ELISA [Ra2]) and one gG-2-based HSV-2-specific immunoblot (Euroimmun anti-HSV-1/HSV-2 gG Western blot [EuW]) was determined with regard to diagnostic performance and cost efficiency. Two hundred fifty serum samples were included in this study, 194 of which were from female prostitutes. When a formal primary "gold standard" was defined based on majority agreement of the commercial tests, with EuW being decisive in stand-off situations, the sensitivity and specificity of the assays in the samples from prostitutes were as follows: Eu2, 100 and 89.22%; Gu2, 94.44 and 96.08%; Ra2, 61.18 and 95.10%; and EuW, 98.90 and 100%. The most cost-effective confirmatory strategy in the samples from prostitutes was screening with Eu2, retesting positive and equivocal samples with Gu2, and resolving the remaining discordant results with EuW (estimated additional costs per sample, 79.02%; sensitivity, 100%; positive predictive value, 96.81%). Applying a self-developed gG-2-independent assay to the discordant and concordant negative samples in the samples from prostitutes suggested that the primary gold standard may have missed six HSV-2-positive samples. In conclusion, confirmatory strategies based on commercial gG-2-dependent seroassays result in an increase in the specificity of HSV-2-specific serology. However, further improvement of the sensitivity of current HSV-2-specific serology may require the additional exploitation of the gG-2-independent type-specific antibody response.