Antibody response to type-common and type-unique epitopes of herpes simplex virus polypeptides

The Role of Exposomes in the Pathophysiology of Autoimmune Diseases II: Pathogens

In our continuing examination of the role of exposomes in autoimmune disease, we use this review to focus on pathogens. Infections are major contributors to the pathophysiology of autoimmune diseases through various mechanisms, foremost being molecular mimicry, when the structural similarity between the pathogen and a human tissue antigen leads to autoimmune reactivity and even autoimmune disease. The three best examples of this are oral pathogens, SARS-CoV-2, and the herpesviruses. Oral pathogens reach the gut, disturb the microbiota, increase gut permeability, cause local inflammation, and generate autoantigens, leading to systemic inflammation, multiple autoimmune reactivities, and systemic autoimmunity. The COVID-19 pandemic put the spotlight on SARS-CoV-2, which has been called “the autoimmune virus.” We explore in detail the evidence supporting this. We also describe how viruses, in particular herpesviruses, have a role in the induction of many different autoimmune diseases, detailing the various mechanisms involved. Lastly, we discuss the microbiome and the beneficial microbiota that populate it. We look at the role of the gut microbiome in autoimmune disorders, because of its role in regulating the immune system. Dysbiosis of the microbiota in the gut microbiome can lead to multiple autoimmune disorders. We conclude that understanding the precise roles and relationships shared by all these factors that comprise the exposome and identifying early events and root causes of these disorders can help us to develop more targeted therapeutic protocols for the management of this worldwide epidemic of autoimmunity.

The Extracellular Domain of Two-component System Sensor Kinase VanS from Streptomyces coelicolor Binds Vancomycin at a Newly Identified Binding Site

The glycopeptide antibiotic vancomycin has been widely used to treat infections of Gram-positive bacteria including Clostridium difficile and methicillin-resistant Staphylococcus aureus. However, since its introduction, high level vancomycin resistance has emerged. The genes responsible require the action of the two-component regulatory system VanSR to induce expression of resistance genes. The mechanism of detection of vancomycin by this two-component system has yet to be elucidated. Diverging evidence in the literature supports activation models in which the VanS protein binds either vancomycin, or Lipid II, to induce resistance. Here we investigated the interaction between vancomycin and VanS from Streptomyces coelicolor (VanSSC), a model Actinomycete. We demonstrate a direct interaction between vancomycin and purified VanSSC, and traced these interactions to the extracellular region of the protein, which we reveal adopts a predominantly α-helical conformation. The VanSSC-binding epitope within vancomycin was mapped to the N-terminus of the peptide chain, distinct from the binding site for Lipid II. In targeting a separate site on vancomycin, the effective VanS ligand concentration includes both free and lipid-bound molecules, facilitating VanS activation. This is the first molecular description of the VanS binding site within vancomycin, and could direct engineering of future therapeutics.

Optimized Expression, Purification of Herpes B Virus gD Protein in Escherichia coli, and Production of Its Monoclonal Antibodies

BACKGROUND

Herpes B virus (BV) is a zoonotic disease caused by double-stranded enveloped DNA virus with cercopithecidae as its natural host. The mortality rate of infected people could be up to 70% with fatal encephalitis and encephalomyelitis. Up to now, there are no effective treatments for BV infection. Among the various proteins encoded by monkey B virus, gD, a conserved structural protein, harbors important application value for serological diagnosis of frequent variations of the monkey B virus.

OBJECTIVES

This study aimed to expressed the gD protein of BV in Escherichia coli by a recombinant vector, and prepare specific monoclonal antibodies against gD of BV to pave the way for effective and quick diagnosis reagent research.

MATERIALS AND METHODS

The gD gene of BV was optimized by OptimWiz to improve codon usage bias and synthesis, and the recombinant plasmid, pET32a/gD, was constructed and expressed in E. coli Rosetta (DE3). The expressed fusion protein, His-gD, was purified and the BALB/c mice were immunized by this protein. Spleen cells from the immunized mice and SP2/0 myeloma cells were fused together, and the monoclonal cell strains were obtained by indirect enzyme-linked immunosorbent assay (ELISA) screening, followed by preparation of monoclonal antibody ascetic fluid.

RESULTS

The optimized gD protein was highly expressed in E. coli and successfully purified. Five monoclonal antibodies (mAbs) against BV were obtained and named as 4E3, 3F8, 3E7, 1H3 and 4B6, and with ascetic fluid titers of 2 × 10(6), 2 × 10(5), 2 × 10(5), 2 × 10(3) and 2 × 10(2), respectively. The 1H3 and 4E3 belonged to the IgG2b subclass, while 3E7, 3F8 and 4B6 belonged to the IgG1 subclass.

CONCLUSIONS

The cell lines obtained in this work secreted potent, stable and specific anti-BV mAbs, which were suitable for the development of herpes B virus diagnosis reagents.

Herpes simplex virus 2 (HSV-2) infected cell proteins are among the most dominant antigens of a live-attenuated HSV-2 vaccine

Virion glycoproteins such as glycoprotein D (gD) are believed to be the dominant antigens of herpes simplex virus 2 (HSV-2). We have observed that mice immunized with a live HSV-2 ICP0^- mutant virus, HSV-2 0ΔNLS, are 10 to 100 times better protected against genital herpes than mice immunized with a HSV-2 gD subunit vaccine (PLoS ONE 6:e17748). In light of these results, we sought to determine which viral proteins were the dominant antibody-generators (antigens) of the live HSV-2 0ΔNLS vaccine. Western blot analyses indicated the live HSV-2 0ΔNLS vaccine elicited an IgG antibody response against 9 or more viral proteins. Many antibodies were directed against infected-cell proteins of >100 kDa in size, and only 10 ± 5% of antibodies were directed against gD. Immunoprecipitation (IP) of total HSV-2 antigen with 0ΔNLS antiserum pulled down 19 viral proteins. Mass spectrometry suggested 44% of immunoprecipitated viral peptides were derived from two HSV-2 infected cells proteins, RR-1 and ICP8, whereas only 14% of immunoprecipitated peptides were derived from HSV-2’s thirteen glycoproteins. Collectively, the results suggest the immune response to the live HSV-2 0ΔNLS vaccine includes antibodies specific for infected cell proteins, capsid proteins, tegument proteins, and glycoproteins. This increased breadth of antibody-generating proteins may contribute to the live HSV-2 vaccine’s capacity to elicit superior protection against genital herpes relative to a gD subunit vaccine.

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.

Herpes simplex virus type-2 specific glycoprotein G-2 immunomagnetically captured from HEp-2 infected tissue culture extracts

Monoclonal antibody H1206 anti-HSV-2 gG-2 bound to tosylactivated paramagnetic Dynabeads (Dynal) has been used to isolate HSV-2 type-specific gG-2 from solubilized HEp-2 HSV-2 infected cell extracts. The immunomagnetically captured type-specific glycoprotein reacted strongly with monoclonal antibody H1206 and demonstrated a single band with apparent molecular weight of 100000 (100 kDa) and a doublet band with an apparent molecular weight of 60000-64000 (60-64 kDa). We observed the same exact banding pattern when monoclonal H1206 was immunoblotted with Helix pomatia lectin purified HSV-2 gG-2. The immunomagnetically purified gG-2 was unreactive to monoclonal antibody H1379 anti-HSV-1 gG-1 and four human HSV antibody negative sera. In addition, 20 human HSV antibody positive sera obtained from the Centers for Disease Control (CDC), Atlanta, GA, were used for the evaluation of our methodology. Immunoblotting of the human HSV antibody positive samples were in agreement with the CDC HSV serological designation. Sera characterized by reactivity to the immunomagnetically purified gG-2 in conjunction with Western blot has the potential to be used as a confirmatory serological test or to determine the accuracy of clinical serological immunoassays used to determine HSV-2 seropositivity.

Prevalence of herpes simplex virus type 2 antibody in Cameroon

BACKGROUND

Genital herpes is one of the most common sexually transmitted diseases. As a leading cause of genital ulceration, herpes genitalis plays a role in facilitating the transmission of HIV. Although HIV infection is most prevalent in Cameroon, information is lacking about prevalence of herpes simplex virus (HSV) type 2 infection in this country.

GOAL

The goal was to determine the prevalence of HSV-2-specific antibody in blood specimens from individuals in Cameroon.

STUDY DESIGN

Blood specimens were randomly collected from 410 clinic attendees (215 males, 195 females) in Douala, the most populous city in Cameroon. One hundred fifteen of the individuals (28.0%) were HIV-infected. Samples were tested by a type-common HSV IgG enzyme immunoassay not discriminating between HSV-1 and HSV-2 antibodies and by two glycoprotein G-2-based enzyme immunoassays for detection of HSV-2-specific antibody.

RESULTS

All but three blood samples were positive for type-common HSV IgG antibodies. Sixty-seven specimens (16.3%) were concordantly negative for HSV-2 antibody by both assays, and 287 (70.0%) specimens were concordantly positive. Fifty-six specimens (13.7%) yielded discrepant results between the two assays.

CONCLUSION

On the basis of specimens with concordantly positive results, the overall HSV-2 seroprevalence was 70.0%. HSV-2 seroprevalence was significantly higher among HIV-infected individuals than among HIV-negative ones. Because of the serious morbidity and mortality caused by HSV-2, effective programs are needed to halt the spread of HSV-2 infection in Cameroon.

Immune response to the herpes simplex type 1 regulatory proteins ICP8 and VP16 in infected persons

The specific immune responses directed against the viral single stranded (ss) DNA binding protein ICP8 and the transactivator of immediate early (IE) gene expression VP16 (alpha-trans inducing factor, Vmw65) in HSV type 1 seropositive humans were examined. The results described in this paper indicate that neither ICP8 nor VP16 were able to induce a recall response in lymphocytes of healthy HSV seropositive individuals without recurrent infection, although CD4+ T cells purified from these individuals responded to both viral proteins in vitro when monocyte derived dendritic cells were used as antigen presenting cells. A recall response, however, could be induced to both viral proteins in T cells of patients with recurrent HSV infections when blood monocytes were used. Moreover, ICP8- and VP16-specific antibodies could be detected in the serum of patients with recurrent HSV infections whereas, in contrast, these antibodies were virtually absent in healthy HSV seropositive individuals without recurrences. These data represent the first systematic study of the immunological properties of ICP8 in humans, indicating a significant difference in the response to the essential viral regulators ICP8 and VP16 in HSV-1 seropositive healthy individuals as opposed to patients with recurrent HSV-1 infections.

Evaluation of three glycoprotein G2-based enzyme immunoassays for detection of antibodies to herpes simplex virus type 2 in human sera

Three new glycoprotein G-based enzyme immunoassays (ETI-HSVK-G 2, Sorin Diagnostics Biomedica [assay A]; HSV Type 2 Specific IgG ELISA, Gull Laboratories, Inc. [assay B]; Cobas Core HSV-2 IgG EIA, Roche [assay C]) for the detection of herpes simplex virus (HSV) type 2 (HSV-2)-specific antibodies were evaluated. By testing sera from 25 individuals with culture-proven HSV-2 infection, the assays showed a sensitivity of 96%. The specificities, evaluated with sera from 70 HSV antibody-negative children, 75 HSV antibody-positive children, and 69 HSV antibody-negative adults, were 100% for assay A, 96.2% for assay B, and 97.8% for assay C, respectively. Discrepant results by any of the three assays, i.e., reactivity of a specimen in only one or two assays, occurred with similar frequencies for HSV-seronegative individuals as well as HSV-seropositive children and adults. For sera with discrepant results, the positive reactivity was mostly low. Thus, for determination of the prevalence of HSV-2 antibodies, only concordantly positive results were considered. On the basis of the results obtained with sera from 41 adults with culture-proven HSV-1 infection and from 173 HSV-antibody-positive pregnant women, the HSV-2 seroprevalence was 9. 8%. The results show that the new glycoprotein G2-based enzyme immunoassays are useful tools for the detection of type-specific HSV-2 antibodies. However, if only one assay is performed, careful interpretation of the results is indicated, especially if the exhibited reactivity is low, and for determination of the definitive HSV-2 serostatus, confirmatory assays may still be necessary.

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.

Herpes Simplex Infections in the Critical Care Setting

Infections caused by herpes simplex virus (HSV) types 1 and 2 are widely prevalent and usually asymptomatic. In the immunocompromised or severely ill patient, however, HSV can cause a variety of mucosal and systemic syndromes. Organ systems most susceptible include the gastrointestinal tract, lungs, and the central nervous system. Systemic disseminated disease may also occur. With the exception of herpes encephalitis, clinical diagnosis of serious HSV infections is difficult, because it occurs in hosts who are susceptible to a wide range of infectious and metabolic problems. We review the presenting syndromes of HSV infection in the critically ill patient, and outline current concepts for diagnosis and treatment.

Locations of herpes simplex virus type 2 glycoprotein B epitopes recognized by human serum immunoglobulin G antibodies

Herpes simplex virus type 2 (HSV-2) glycoprotein B (gB-2) gene segments were expressed as recombinant proteins in Escherichia coli. gB-2 recombinant proteins were reacted with human serum immunoglobulin G (IgG) antibodies in Western immunoblot assays. Initially, samples were tested for the presence of HSV-1-specific antibodies and HSV-2-specific antibodies by using HSV-infected cell lysates as antigen targets in Western blot assays. Serum samples that contained HSV-2-specific IgG (n = 58), HSV-1-specific IgG (n = 33), or no detectable HSV antibodies (n = 31) were tested for reactivities with the gB-2 recombinant proteins. In 58 of 58 samples that contained HSV-2-specific IgG, antibodies were present that reacted strongly with a gB-2 amino-proximal segment between amino acids (aa) 18 and 75. Three of 33 serum samples that contained HSV-1- and not HSV-2-specific IgG (as defined by the HSV lysate Western blot assay) reacted with this segment. Both HSV-2 antibodies and HSV-1 antibodies reacted strongly with a carboxy-terminal gB-2 segment between aa 819 and 904; a second minor cross-reactive region was mapped to a gB-2 segment between aa 564 and 626. The gB-2 segment from aa 18 to 75 may constitute a useful reagent for the virus type-specific serodiagnosis of HSV-2 infections. Further studies will be required to determine the relative sensitivities and specificities of the assay for gB-2 aa 18 to 75, HSV gG assays, and HSV lysate Western blot assays for detecting virus type-specific antibody responses in acute and chronic HSV-2 infections.

Demonstration of either endogenous recurrence or exogenous reinfection by restriction endonuclease cleavage analysis of herpes simplex virus from patients with recrudescent genital herpes

By using restriction endonuclease (RE) cleavage analysis, either endogenous recurrence or exogenous reinfection of herpes simplex virus (HSV) was clarified in 45 male and 20 female subjects with recrudescent genital herpes. All of the plural (two to ten) isolates from 63 (205 isolates) out of 65 subjects (97%) were HSV-2. Two isolates from only one of 65 subjects (1.5%) were HSV-1, and they showed the same RE profile. In addition, an HSV-1 and five HSV-2 isolates were obtained from the remaining one female patient (1.5%), indicating that an exogenous HSV-1 strain has been reinfected during HSV-2 recrudescences. HSV-2 isolates were furthermore classified into genotypes of HSV-2 using 16 different RE markers with five REs. Two hundred and ten HSV-2 isolates from 64 subjects were classified into 27 distinct genotypes, in which some predominant genotypes and seven new genotypes were found. Plural HSV-2 isolates obtained from 63 out of 64 subjects, including one subject from whom an HSV-1 and five HSV-2 strains were isolated, were classified into the same genotypes, indicating that they may be regarded as recrudescent genital herpes by the reactivation of the same endogenous strain. However, the RE profiles of two HSV-2 strains from the remaining one subject were different. Thus, it was finally found that only two out of 65 subjects (3%) were reinfected with exogenous strains. These results lead to the conclusion that almost all recrudescent genital herpes are due to the reactivation of an initially infected HSV-2 strain, and are occasionally due to reinfection with distinct HSV strains of either the same or a different type.

Detection of immunoglobulin M antibodies to glycoprotein G-2 by western blot (immunoblot) for diagnosis of initial herpes simplex virus type 2 genital infections

Western blots (immunoblots) for the detection of immunoglobulin M (IgM) antibodies specific for herpes simplex virus type 1 (HSV-1) and HSV-2 in patients' sera were developed. The locations of the type-specific glycoprotein G (gpG-2) of HSV-2 (92- and 140-kDa forms) and glycoprotein C of HSV-1 (gpC-1), which carries mostly type-specific antigenic epitopes, were checked with specific monoclonal antibodies. Western blot assays for IgM antibody to gpC-1 or gpG-2 were performed after depletion of IgG by precipitation with anti-human IgG. In patients with primary HSV-2 genital infections, seroconversion of IgM and IgG antibodies to both the 92- and 140-kDa forms of gpG-2 was observed, although both antibodies appeared in convalescent-phase serum after the first week. IgM and IgG antibodies to low-molecular-size polypeptides (40 to 65 kDa) were the first antibodies observed in patients with primary infection, but these antibodies were cross-reactive with HSV-1 and HSV-2. However, in patients with recurrent HSV-2 infections, IgG antibodies to both forms of gpG-2 and the low-molecular-size polypeptides were found no matter how early after onset the patient was bled, and IgM to gpG-2 did not appear. In patients with nonprimary initial genital HSV-2 infections, IgG antibody to HSV-1 was demonstrated in the first serum specimen, and HSV-2-specific IgM was found in 39% of the serum specimens. Hence, the Western blot assay can be used to test for IgM antibody to gpG-2, allowing for the retrospective diagnosis of inital HSV-2 infections and its use as a supplementary test to the gpG-2 IgG enzyme-linked immunosorbent assays developed elsewhere. In contrast, IgM antibody to gpG-2 is not usually detected in patients with recurrent HSV-2 infections.

Herpes simplex virus type 2 infection in pregnancy: asymptomatic viral excretion at delivery and seroepidemiologic survey of two socioeconomically distinct populations in São Paulo, Brazil

The objective of the present study was to estimate the prevalence of herpes simplex virus type 2 (HSV 2) antibodies in child bearing women of 2 Brazilian populations with different socioeconomic status and to determine the risk of neonatal HSV exposure by means of maternal cultures at the onset of labor. The study was conducted at 2 hospitals: A, serving very low income patients and B, serving middle socioeconomic class. 173 participants from group A and 127 from B answered a questionnaire which showed that the patients had similar ages (27.7 and 26.8 years, respectively) but differed with regard to socioeconomic status, age at first intercourse (18.6 vs 20.6 years), number of sex partners (1.5 vs 1.2) and previous sexually transmitted diseases (15% vs. 1.5%). History of genital herpes was given by 11% of group A participants and by a similar number, 7%, of patients from group B. In addition, 200 serum samples from population A and 455 from B were tested by ELISA for anti HSV antibodies and 92% and 86%, respectively, were found to be positive. Sixty seropositive samples from group A and 90 from B were further analyzed by Western blot, which showed the presence of type 2 specific antibodies in 46% and 36%, respectively, suggesting an overall HSV 2 prevalence of 42% in group A and 31% in B. Cervical specimens were obtained for culture from 299 asymptomatic patients of population A and 313 of B. HSV was isolated from one specimen in each group, indicating a 0.3% incidence of asymptomatic viral excretion in both populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Highly sensitive enhanced chemiluminescence immunodetection method for herpes simplex virus type 2 Western immunoblot

Three Western blot (immunoblot) methods for detecting antibodies to herpes simplex virus type 2 were compared: (i) nitrocellulose blots with 4-chloro-1-naphthol immunostaining (4CN-WB); (ii) polyvinylidene difluoride (PVDF) blots with 3,3',5,5'-tetramethylbenzidene immunostaining (TMB-WB); and (iii) PVDF blots with enhanced chemiluminescence (ECL-WB). TMB-WB was 10-fold more sensitive than 4CN-WB, while ECL-WB was as much as 500-fold more sensitive.

Genital herpes simplex virus infections

There has been a dramatic increase in patient visits to physicians for evaluation and treatment of genital herpes infections. This has resulted in part from an increase in genital herpes infections, particularly severe, first-episode genital herpes infections in adults without prior HSV-1 infection. Virus culture remains the most sensitive and specific method for diagnosis, and use of viral cultures is encouraged. Type-specific antibody tests have been employed in studies documenting the role of asymptomatic shedding of HSV in transmission of genital infections, the role of genital HSV in transmission of HIV, the predominance of asymptomatic and unrecognized infections in those infected with HSV-2, and the presence of past asymptomatic or unrecognized acquisition of HSV-2 in 25% of persons presenting with first-episode genital herpes. Unfortunately, commercially available serologic tests do not reliably differentiate between antibody to HSV-1 and HSV-2. Recent studies suggest that the annual risk of transmission from a sexual partner with genital herpes is about 10% in heterosexual couples. Currently, promotion of "safe sex" is the only available approach for prevention of transmission. However, ongoing research is focused on the development of an effective vaccine. Acyclovir should be used routinely in persons with first-episode genital herpes, but careful evaluation is needed in persons with recurrent genital herpes to determine whether episodic or suppressive treatment is indicated. Acyclovir should also be used routinely for episodic or suppressive treatment of HSV infections in persons with AIDS. Additional antiviral agents are needed for more effective suppressive therapy and for treatment of ACV-resistant HSV infections in the immunocompromised host.

Identification of herpes simplex viruses by automated profile analysis of viral proteins

In this report we describe a computerized virus identification system based upon the fact that viral proteins, separated by one-dimensional (ID) SDS-PAGE have unique banding patterns (protein profiles). Fifty-eight clinical strains of herpes simplex virus (HSV) were correctly identified by comparing their protein profiles with reference profiles of HSV, other viruses and uninfected cell cultures stored in a computer data base.

Golgi-like, transneuronal retrograde labelling with CNS injections of herpes simplex virus type 1

The use of HSV1 as a retrograde transneuronal marker for the CNS was assessed in several neuroanatomical systems of the rat brain including the olfactory, visual and somatosensory systems. In all systems, retrograde transneuronal transport was observed; with appropriate survival times transport was evident in third and fourth order neurons in established neuronal circuits. A striking observation was the high frequency of neurons labelled in a Golgi-like manner. The visualization of even the finest dendritic processes provides information about the architecture of neurons several synapses removed from the site of injection. The Golgi-like labelling is so complete that it is possible to identify and process distal parts of dendrites for EM analysis. Thus, it should be feasible to identify synaptic inputs to the dendrites of neurons two or more synapses removed from the site of injection. There was spotty evidence for anterograde transport but the vast majority of the labelling could be accounted for by retrograde transport. With increased survival time, some regions, especially those located one synapse removed from the injection site, became necrotic and the virus spread to glia cells in addition to neurons in those regions. However, in regions more than one synapse removed from the injection there was negligible labelling of glial cells. Taken together, these results suggest that transneuronal retrograde labelling with HSV1 is a useful tool in the analysis of neural circuits.

Use of densitometric analysis for interpreting HSV serologies based on Western blot

Western blot assays have been described for detecting antibodies to herpes simplex virus (HSV). A predominance of antibody binding to either the HSV-1 or the HSV-2-containing blot has been reported to indicate infection with HSV-1 or HSV-2, respectively. By densitometry, differential binding of total antibody on HSV-1 versus HSV-2 strips can be expressed as a ratio. To determine the clinical correlation of these ratios, sera from 81 patients with culture-proven oral or genital herpes were tested by Western blot (WB) and densitometry. Binding ratios accurately identified patients with primary HSV-2 infections. However, ratios on sera with HSV-1 antibody or dual antibody status showed considerable overlap. Densitometry was shown to amplify and clarify the band corresponding to the HSV-2 specific glycoprotein gG-2 and was useful, in this respect, for detecting HSV-2 antibody in the presence of HSV-1 antibody. Sera from 52 patients with asymptomatic HSV-1, HSV-2 or dual infection were also tested by WB. Typing results were confirmed by cross-adsorption of sera ("adsorption blot assay"). Ratios of HSV-2 to HSV-1 binding were higher in asymptomatic versus symptomatic patients with dual antibody (P less than 0.01). Ratios for those with HSV-1 or HSV-2 antibody types were not affected by disease expression.

Analysis of the IgM and IgG antibody response against herpes simplex virus type 1 (HSV-1) structural and nonstructural proteins

In the present study the reactivity of IgG and IgM antibodies against HSV-1 structural and nonstructural proteins was analyzed by Western blot analysis (WBA) and radioimmunoprecipitation followed by polyacrylamide gel electrophoresis (RIPA-PAGE). It was demonstrated that IgM and IgG antibodies were directed against viral immediate-early, early, and late proteins. Following acute primary HSV infection, the early IgM antibody response in general was found to be directed against nonglycosylated structural proteins, viral early and immediate-early polypeptides. IgM antibodies against viral glycoproteins were found inconsistently. IgG antibodies against viral glycoproteins and other structural proteins with an apparent molecular weight of 56 kD, 45 kD, and 39 kD could be detected early in infection. Viral early and immediate-early proteins were poorly recognized by IgG antibodies in acute primary infections. In recurrent HSV infections, IgM antibodies revealed a less complex reaction with viral polypeptides. Thus, such IgM antibodies reacted predominantly with viral nonglycosylated structural proteins. In contrast, IgG antibodies from patients with recurrent infections strongly recognized viral structural, early, and immediate-early proteins. In seropositive individuals without obvious symptoms of acute infection, the most prominent antibody response was directed against gB and gD.

Type specificity of complement-fixing antibody against herpes simplex virus type 2 AG-4 early antigen in patients with asymptomatic infection

We evaluated the type specificity of complement-fixing (CF) antibody against the AG-4 early antigen of herpes simplex virus (HSV) type 2 (HSV-2) by comparing a commercial AG-4 CF kit (Simplex-2; Gene Link Australia, Inc., Princeton, N.J.) with quantal microneutralization (MN) and absorption-Western blotting in testing sera from patients with and without a history of genital herpes. Sera characterized as HSV type 1 (HSV-1) or HSV-2 positive or negative by MN were selected and tested by CF, and those with discordant results were further analyzed for specific antibodies by absorption with HSV-1 or HSV-2 antigen and Western blotting with heterologous HSV proteins. A total of 34 of 42 (81%) sera HSV-2 positive by MN, 19 of 43 (44%) sera HSV-1 positive by MN, and 0 of 19 sera negative by MN were positive by CF. Absorption-Western blotting showed that 12 of 18 (67%) sera HSV-1 positive by MN but positive by CF had no HSV-2-specific antibody and that all 7 sera HSV-2 positive by MN but negative by CF had HSV-2-specific antibody. When MN and absorption-Western blotting data were combined to analyze patients with no history of genital herpes, 7 of 19 (37%) with no HSV-2-specific antibody were positive by CF, and 7 of 27 (26%) with HSV-2-specific antibody were negative by CF. The positive and negative predictive values for the CF test were 78 and 75%, respectively, in this group. The presence of antibody to the HSV AG-4 antigen does not discriminate sufficiently between HSV-1- and HSV-2-infected patients to be of value in predicting HSV-2 infection in the absence of symptomatic disease.