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

The Dilemma of HSV-1 Oncolytic Virus Delivery: The Method Choice and Hurdles

Oncolytic viruses (OVs) have emerged as effective gene therapy and immunotherapy drugs. As an important gene delivery platform, the integration of exogenous genes into OVs has become a novel path for the advancement of OV therapy, while the herpes simplex virus type 1 (HSV-1) is the most commonly used. However, the current mode of administration of HSV-1 oncolytic virus is mainly based on the tumor in situ injection, which limits the application of such OV drugs to a certain extent. Intravenous administration offers a solution to the systemic distribution of OV drugs but is ambiguous in terms of efficacy and safety. The main reason is the synergistic role of innate and adaptive immunity of the immune system in the response against the HSV-1 oncolytic virus, which is rapidly cleared by the body's immune system before it reaches the tumor, a process that is accompanied by side effects. This article reviews different administration methods of HSV-1 oncolytic virus in the process of tumor treatment, especially the research progress in intravenous administration. It also discusses immune constraints and solutions of intravenous administration with the intent to provide new insights into HSV-1 delivery for OV therapy.

Distinguishing Features Common to Dual Fatal Herpes Simplex Virus Infections That Occur in Both a Pregnant Woman and Her Newborn Infant

Deaths from herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) are rare. A major exception is perinatally acquired HSV-1 or HSV-2 infection where the neonatal death rate is substantial. Fatal HSV infection also occurs occasionally in pregnant women. The goal of this review is to enumerate the reports that describe dual deaths of both a pregnant woman and her newborn from a herpesvirus infection. A total of 15 reports were found in the medical literature, of which five described pregnant women with HSV encephalitis and 10 described women with disseminated HSV infection. When the virus was typed, most cases of dual mother/newborn deaths were caused by HSV-2. Of interest, in two situations caused by HSV-1, the pregnant woman probably acquired her primary HSV-1 infection from one of her children and not by sexual transmission. Complete genomic sequencing was performed on one set of HSV-1 isolates collected from mother (blood) and newborn (blood and skin). The mother's strain and the newborn's skin strain were 98.9% identical. When the newborn's two strains were compared, they were 97.4% identical. Only one mother was tested by the HerpeSelect IgG antibody kit. During the nine days of her undiagnosed disseminated infection preceding her death, her serology was negative. In summary, although dual mother/newborn deaths from HSV infection are rare, they continue to be reported as recently as 2017.

Percent of highly immunogenic amino acid residues forming B-cell epitopes is higher in homologous proteins encoded by GC-rich genes

We analyzed the dependence of the percent of highly immunogenic amino acid residues included in B-cell epitopes of homologous proteins on the GC-content (G+C) of genes coding for them in twenty-seven lineages of proteins (and subsequent genes), which belong to seven Varicello and five Simplex viruses. We found out that proteins encoded by genes of a high GC-content usually contain more targets for humoral immune response than their homologs encoded by GC-poor genes. This tendency is characteristic not only to the lineages of glycoproteins, which are the main targets for humoral immune response against Simplex and Varicello viruses, but also to the lineages of capsid proteins and even "housekeeping" enzymes. The percent of amino acids included in linear B-cell epitopes has been predicted for 324 proteins by BepiPred algorithm (www.cbs.dtu.dk/services/BepiPred), the percent of highly immunogenic amino acids included in discontinuous B-cell epitopes and the percent of exposed amino acid residues have been predicted by Epitopia algorithm (http://epitopia.tau.ac.il/). Immunological consequences of the directional mutational GC-pressure are mostly due to the decrease in the total usage of highly hydrophobic amino acids and due to the increase in proline and glycine levels of usage in proteins. The weaker the negative selection on amino acid substitutions caused by symmetric mutational pressure, the higher the slope of direct dependence of the percent of highly immunogenic amino acids included in B-cell epitopes on G+C.

Impact of valency of a glycoprotein B-specific monoclonal antibody on neutralization of herpes simplex virus

Herpes simplex virus (HSV) glycoprotein B (gB) is an integral part of the multicomponent fusion system required for virus entry and cell-cell fusion. Here we investigated the mechanism of viral neutralization by the monoclonal antibody (MAb) 2c, which specifically recognizes the gB of HSV type 1 (HSV-1) and HSV-2. Binding of MAb 2c to a type-common discontinuous epitope of gB resulted in highly efficient neutralization of HSV at the postbinding/prefusion stage and completely abrogated the viral cell-to-cell spread in vitro. Mapping of the antigenic site recognized by MAb 2c to the recently solved crystal structure of the HSV-1 gB ectodomain revealed that its discontinuous epitope is only partially accessible within the observed multidomain trimer conformation of gB, likely representing its postfusion conformation. To investigate how MAb 2c may interact with gB during membrane fusion, we characterized the properties of monovalent (Fab and scFv) and bivalent [IgG and F(ab')(2)] derivatives of MAb 2c. Our data show that the neutralization capacity of MAb 2c is dependent on cross-linkage of gB trimers. As a result, only bivalent derivatives of MAb 2c exhibited high neutralizing activity in vitro. Notably, bivalent MAb 2c not only was capable of preventing mucocutaneous disease in severely immunodeficient NOD/SCID mice upon vaginal HSV-1 challenge but also protected animals even with neuronal HSV infection. We also report for the first time that an anti-gB specific monoclonal antibody prevents HSV-1-induced encephalitis entirely independently from complement activation, antibody-dependent cellular cytotoxicity, and cellular immunity. This indicates the potential for further development of MAb 2c as an anti-HSV drug.

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.

Multiple viral/self immunological cross-reactivity in liver kidney microsomal antibody positive hepatitis C virus infected patients is associated with the possession of HLA B51

Liver Kidney Microsomal autoantibody type 1(LKM1) directed to cytochrome P4502D6 (CYP2D6) characterises autoimmune hepatitis type-2 (AIH-2), but is also found in a proportion of chronic hepatitis C virus (HCV) infected patients, CYP2D6252-271 being a major B- cell autoepitope. Molecular mimicry and immunological cross-reactivity between CYP2D6252-271, HCV polyprotein and the infected cell protein 4 (ICP4) of herpes simplex virus type 1 (HSV-1) have been suggested as triggers for the induction of LKM1, but reactivity and cross-reactivity to the relevant sequences have not been investigated experimentally. CYP2D6252-271 and its viral homologues were constructed and tested by ELISA in the sera of 46 chronically infected HCV patients, 23 of whom were LKM1 positive. Reactivity to the E1 HCV and ICP4 HSV1 mimics was frequently found in HCV infected patients irrespectively of their LKM1 status; viral/self cross-reactivity (as indicated by inhibition studies), however, was present in the only 2 of the 23 LKM1 seropositive HCV patients, who possessed the HLA allotype B51. Our results indicate that in HCV infected patients virus/self cross-reactivity is dependent on a specific immunogenetic background, a finding awaiting confirmation by studies in larger series of patients.

Immunogenicity of a DNA vaccine against herpes B virus in mice and rhesus macaques

Herpes B virus (Cercopithecine herpesvirus 1) is endemic in captive macaque populations and poses a serious threat to humans who work with macaques or their tissues. A vaccine that could prevent or limit B virus infection in macaques would lessen occupational risk. To that end, a DNA vaccine plasmid expressing the B virus glycoprotein B (gB) was constructed and tested for immunogenicity in mice and macaques. Intramuscular (IM) or intradermal (ID) immunization in mice elicited antibodies to gB that were relatively stable over time and predominately of the IgG2a isotype. Five juvenile macaques were immunized by either IM+ID (n=2) or IM (n=3) routes, with two booster immunizations at 10 and 30 weeks. All five animals developed antibodies to B virus gB, with detectable neutralizing activity in the IM+ID immunized animals. These results demonstrated that DNA immunization can be used to generate an immune response against a B virus glycoprotein in uninfected macaques.

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.

Detection of human serum antibodies against type-specifically reactive peptides from the N-terminus of glycoprotein B of herpes simplex virus type 1 and type 2 by surface plasmon resonance

A single-step surface plasmon resonance protocol for the detection of antibodies against herpes simplex virus type 1 and type 2 (HSV-1, HSV-2) in human sera was established using the BIAcore system. Two peptides from corresponding segments of the N-terminus of HSV-1 and HSV-2 glycoprotein B (gB), i.e. peptide gB-1 (60-73) (GAAPTGDPKPKKNK) and peptide gB-2 (55-68) (SPATTKARKRKTKK), were identified as immunogenic. Employing both peptides as diagnostic antigens in the surface plasmon resonance assay, a sensitivity for the detection of HSV-1 and HSV-2 type-specific antibodies of 83 and 86%, respectively, was achieved as compared with immunoblotting as a reference method. Peptide gB-1 (60-73) allowed the discrimination between HSV-1 and HSV-2 type-specific antibodies with a specificity of 67%, whereas peptide gB-2 (55-68) reacted in a strictly HSV-2 type-specific manner. It is concluded that peptides from the N-terminus of gB-1 and gB-2 are recognized predominantly by human sera in an HSV-specific manner. Peptide gB-2 (55-68) can be employed successfully for the determination of type-specific antibodies against HSV-2.

Bell's palsy associated with herpes simplex gingivostomatitis. A case report

Bell's palsy is a sudden, isolated, peripheral facial paralysis caused by various known and sometimes unknown factors. The case of an 18-year-old man who developed Bell's palsy after onset of primary herpetic gingivostomatitis is presented. Although Bell's palsy has already been associated with herpes simplex virus type 1, the described case is the first in the literature in which enzyme-linked immunosorbent assays for immunoglobulin G to herpes simplex virus type 1 and herpes simplex virus type 1 culture were both positive. The recent literature regarding the possible relationship between herpes simplex virus type 1 and Bell's palsy is reviewed and discussed.

Mapping of linear antigenic determinants on glycoprotein C of herpes simplex virus type 1 and type 2 recognized by human serum immunoglobulin G antibodies

Using membrane-based dekapeptides, the reactivity of human serum antibodies with linear antigenic determinants of herpes simplex virus (HSV) type 1 and type 2 glycoprotein C (gC-1, gC-2) was studied by pep scan and immunodot assay. The entire coding sequences of gC-1 and gC-2 were screened for the presence of linear epitopes by pep scan. Peptides recognized in an HSV-1 type-specific manner were mainly identified within the N-terminal third and at the C-terminus of gC-1, whereas most type-common antibodies were directed against colinear peptides within the central parts of gC-1 and gC-2. The type-specific reaction of human sera with gC-2 peptides in pep scan was poor. Eight peptides identified as immunoreactive by pep scan were further tested in immunodot assay for their reactivity with a human serum panel. None of the eight HSV-negative sera gave positive results by immunodot assay. Positive reactions with gC peptides were found to be strongly age-dependent, i.e., the rate of positive reactions was significantly higher in HSV-positive adults than in HSV-positive children. Antibody reactivity with two type-common gC peptides was demonstrated in 17 out of 28 HSV-positive sera. A putative type-specific gC-2 peptide employed in immunodot assay was inconsistently recognized by human sera. Twenty HSV-positive sera reacted with at least 1 of 5 type-specific gC-1 peptides. Nine sera showing no reactivity with glycoprotein G of HSV-1 (gG-1) by immunobloting recognized type-specific gC-1 peptides in immunodot assay. Thus, gC-1 peptides might allow the detection of HSV-1-specific antibodies in individuals showing no reactivity with commonly employed HSV-1-specific diagnostic antigenes, i.e., purified or recombinant gG-1.

Recrudescent herpes simplex infection mimicking primary herpetic gingivostomatitis

We report six cases of recrudescent intraoral herpes simplex infection clinically indistinguishable from primary herpetic gingivostomatitis. All infections occurred in healthy children or young adults. Serological analysis demonstrated herpes simplex virus (HSV)-specific IgG at initial presentation, indicating that the infection was not a primary infection. Convalescent sera exhibited HSV-specific IgM and a rising HSV-specific IgG titre. These findings demonstrate that the initial clinical diagnosis of primary herpetic gingivostomatitis was erroneous and that what was actually being observed was widespread recrudescent intraoral herpes simplex infection.

Recombinant human Fab to glycoprotein D neutralizes infectivity and prevents cell-to-cell transmission of herpes simplex viruses 1 and 2 in vitro

Herpes simplex viruses 1 and 2 (HSV-1 and -2) are associated with a number of conditions of varying severity, which are only partially responsive to current therapies. Human antibodies to the viruses offer a potential alternative. We describe here the generation of panels of human monoclonal Fab fragments to HSV-1 and -2 by panning a phage display combinatorial antibody library against whole lysates from the two viruses. Each lysate selected a largely distinct set of Fabs, although all of the Fabs were cross-reactive with both viruses. In a plaque-reduction assay, one Fab neutralized HSV-1 at 0.25 microgram/ml (50% reduction) and HSV-2 at 0.05 microgram/ml. This Fab also inhibited plaque formation when applied to virus-infected monolayers, completely abolishing HSV-2 plaque development at 25 micrograms/ml 72 hr postinfection, indicating the ability of the Fab to prevent cell-to-cell spread of virus. The Fab was shown to recognize viral glycoprotein D and to neutralize virus primarily by a postattachment mechanism. Recombinant Fabs may be useful for topical administration, although whole antibody will probably be required for systemic use.

Immunoglobulin M antibody response to measles virus following primary and secondary vaccination and natural virus infection

The use of IgM antibody detection for the classification of the primary and secondary measles antibody response in persons following primary and secondary vaccination and natural measles virus infection was examined. Of 32 nonimmune children receiving primary measles vaccination, 31 (97%) developed IgM antibodies, consistent with a primary antibody response. Of 21 previously vaccinated children with low levels of preexisting IgG antibodies who responded to revaccination, none developed detectable IgM antibodies, whereas 33 of 35 (94%) with no detectable preexisting IgG antibodies developed an IgM response. Of a sample of 57 measles cases with a prior history of vaccination, 55 (96%) had detectable IgM antibodies. Of these, 30 (55%) were classified as having a primary antibody response and 25 (45%) a secondary antibody response based on differences in their ratios of IgM to IgG antibodies. Differences in the severity of clinical symptoms between these 2 groups were consistent with this classification scheme. These findings suggest that 1) an IgM response follows primary measles vaccination in the immunologically naive, 2) an IgM response is absent on revaccination of those previously immunized, and 3) an IgM response may follow clinical measles virus infection independent of prior immunization status.

Recrudescence of herpes simplex virus type 1 in latently infected rats after trauma to oral tissues

Tooth extraction in rats was used to trigger a latent HSV-1 infection. HSV-1 was inoculated unilaterally in the rat palates. Eight weeks later two molars were removed bilaterally. The trigeminal ganglia were co-cultivated and HSV-1 was isolated from 63% of the ganglia on the infected sides but from only 11% on control sides. The immune response pattern was analysed by immunoblotting of rat serum, and strong reactivity to HSV-1 specific cell polypeptides and glycoproteins (ICP6, gC, pgC, gD) was seen after reactivation. The extraction sockets were histopathologically evaluated and showed healing on the infected side in 26% compared to 63% in contralateral control sockets. The effect of acyclovir (ACV) treatment was elucidated and was found to influence the subsequent development of antibodies and to promote healing of the sockets. Vesiculation in intra- and subepithelial tissue was present on the infected side in 58% but in only 12% of ACV-treated animals. The present study in rats has shown that a latent HSV-1 infection can be established and reactivated by tooth extraction. Reactivation resulted in delayed healing of sockets on the latently infected side but not on the contralateral control side. HSV-1 reactivation was demonstrated serologically by immunoblotting. Healing was significantly promoted by administration of ACV, which also supports the contention that HSV-1 interferes with the healing process.

Antibody to a mutagenic peptide of herpes simplex virus in young adult patients with cancer of the head and neck

Cancer of the head and neck has been associated with herpes simplex virus type-1 by serologic studies that have used virus particles or complex mixtures of viral proteins as antigens. Recently a peptide was found to be encoded by the transforming region of the virus that is mutagenic and is postulated to be involved in cell transformation. Sera from young adult patients with head and neck cancer and from control subjects were examined for the presence of antibody to this peptide with the use of an enzyme-linked immunosorbent assay. Antibody to the peptide was detected in many sera and showed a significant correlation with antibody to the virus in sera from control subjects. Antipeptide antibodies were largely of the IgM isotype, and patients had significantly higher levels of antibody than control subjects. This study is consistent with an association between HSV-1 and head and neck cancer and suggests that this viral peptide should be investigated further for its role in carcinogenesis.

Reactivated herpes simplex virus infection as a possible cause of dry socket after tooth extraction

This study was designed to evaluate a possible association between reactivated herpes simplex virus type 1 (HSV-1) infection after lower third molar extraction and development of dry socket (DS). The HSV-1 antibody response was analyzed before and after tooth removal by enzyme-linked immunosorbent assay and immunoblotting in 208 patients. History of previous possible oral herpes reactivation was evaluated by a questionnaire that was based on self-rated frequency of oral cold sores. Tobacco users were identified. The anatomic proximity of the root apex to the mandibular nerve canal was classified radiographically before extraction. Fifteen patients (7%) developed DS after tooth extraction. Eleven of the 15 DS patients (73%) were HSV seropositive as compared with 7 of 15 (47%) in the matched control group. Seven of the 11 seropositive DS patients have shown HSV-1 reactivation by an increase of specific polypeptides, predominantly gB, gC, gD and ICP 4 and 6, in the immunoblot test. No change in HSV-1 reactivity was observed in control sera. DS patients reported a high frequency of oral cold sores (64%) compared with the controls (33%). Tobacco use was not found to influence the frequency of cold sores or the development of DS. A close radiographic proximity between the mandibular canal and root apex was more common (P < .05) in DS patients. The results indicate that extraction of a mandibular third molar could be a possible cause of reactivation and recurrence of an HSV-1 infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Replication-defective mutants of herpes simplex virus (HSV) induce cellular immunity and protect against lethal HSV infection

Live viruses and live virus vaccines induce cellular immunity more readily than do inactivated viruses or purified proteins, but the mechanism by which this process occurs is unknown. A trivial explanation would relate to the ability of live viruses to spread and infect more cells than can inactivated virus. We have used live but replication-defective mutants to investigate this question. Our studies indicate that the immune responses of mice to live virus differ greatly from the responses to inactivated virus even when the virus does not complete a replicative cycle. Further, these studies indicate that herpes simplex virus-specific T-cell responses can be generated by infection with replication-defective mutant viruses. These data indicate that the magnitude of the cellular immunity to herpes simplex virus may be proportional to the number or quantity of different viral gene products expressed by an immunizing virus.

The diagnostic significance of the polymerase chain reaction and isoelectric focusing in herpes simplex virus encephalitis

In this study, serum and CSF samples of 55 neurological patients have been examined to confirm the diagnosis of herpes simplex virus encephalitis (HSVE). Different methods were applied, including serological titer evaluations, determination of intrathecally-produced HSV-specific antibodies by isoelectric focusing with affinity immunoblotting (IEF), as well as HSV-specific ELISA and HSV-specific polymerase chain reaction (PCR). The results of IEF and PCR have been compared and contrasted to develop general directions for virological diagnosis of HSVE. Of 14 patients suffering from clinically diagnosed HSVE, HSVE was confirmed in 12 cases by the demonstration of PCR or IEF positivity. A HSV-specific CNS infection could be excluded in 2 of these 14 patients. In 17 patients suffering from non-HSVE, PCR and IEF results were negative. Twenty-four patients, suffering from other neurological diseases, serving as a control group, were PCR- and HSV-IEF-negative. The study indicated that there are two possibilities for unequivocal demonstration of HSV-specific CNS involvement: first, performance of PCR especially in the acute phase of disease and in suspicious relapses, and second, performance of HSV-specific IEF for determination of intrathecally synthesized HSV-specific antibodies. It is suggested that these two methods should be introduced in routine diagnosis of viral encephalitis.

HSV-1 gB and VZV gp-II crossreactive antibodies in human sera

The specificity and prevalence of human IgG antibodies crossreactive between HSV-1 (ANG) and VZV (Ellen) was examined in immunoblots. Using antibody fractions purified on HSV- and VZV-coated affinity chromatography columns and by preadsorption of sera with HSV and/or VZV lysates a crossreactivity between HSV-1 gB and VZV gp-II was demonstrated. Crossreaction of human IgG antibodies among other structural and nonstructural viral proteins, however, was not detected. The frequency of human IgG antibodies crossreactive between HSV-1 gB and VZV gp-II was highest in HSV-seropositive patients experiencing an acute primary VZV infection (4 out of 5 sera tested). In contrast, no crossreactive antibodies were found in sera of HSV-seronegative patients with acute primary VZV infection (0/6) or in sera from individuals with acute recurrent HSV or VZV infection (0/12). Analysis of sera from individuals with previous HSV and/or VZV infection showed the presence of antibodies crossreactive between HSV-1 gB and VZV gp-II in 3 out of 30 sera tested.

Reactivity of human sera with overlapping synthetic peptides of herpes simplex virus type 1 glycoprotein D

Thirty eight human sera, seropositive for herpes simplex virus (HSV) and 56 human sera, seronegative for HSV by immunofluorescence and by ELISA, were investigated for reactivity with a series of overlapping synthetic peptides of HSV type 1 glycoprotein D (gD-1). Thirty four out of the 38 human sera positive for HSV reacted with peptides located between residues 300 and 369; the HSV-negative sera reacted with six of the gD-1 peptides, but with none of the peptides within residues 300 to 369.

Fine specificities of antibodies in sera and cerebrospinal fluid in herpes virus infections of the central nervous system as detected by the antigen variable immunoblot technique

Applying the immunoblot technique a sensitive and specific method was developed for the detection of intrathecally synthesized antibodies against individual specific proteins that are antigens of various infectious agents causing encephalitis. Paired serum and cerebrospinal fluid (CSF) samples from five patients with herpes virus infections of the central nervous system (CNS) (three herpes simplex virus encephalitis, one varicella zoster virus encephalitis, one zoster ganglionitis) were investigated for the presence of locally produced IgG against the electrophoretically separated antigens of herpes simplex virus (HSV), varicella zoster virus (VZV) and human cytomegalovirus (HCMV), as well as for IgM antibodies in one case of HSV encephalitis. In two cases (HSV encephalitis and VZV encephalitis) four and one antibody, respectively, were found that were synthesized intrathecally only. In the other cases the patterns of sera and CSF antibodies were similar, the CSF antibodies showing an all-over stronger reaction, at identical IgG concentrations. In contrast to the conception of a 'limited heterogeneity' of intrathecal antibody synthesis in encephalitis, we thus found an 'expanded heterogeneity' of the intrathecally synthesized antibodies in comparison to the corresponding serum antibodies.

Identification of herpes simplex virus type 1 glycoproteins interacting with the cell surface

To investigate the interaction of herpes simplex virus type 1 (HSV-1) with the cell surface, we studied the formation of complexes by HSV-1 virion proteins with biotinylated cell membrane components. HSV-1 virion proteins reactive with surface components of HEp-2 and other cells were identified as gC, gB, and gD. Results from competition experiments suggested that binding of gC, gB, and gD occurred in a noncooperative way. The observed complex formation could be specifically blocked by monospecific rabbit antisera against gB and gD. The interaction of gD with the cell surface was also inhibited by monoclonal antibody IV3.4., whereas other gD-specific monoclonal antibodies, despite their high neutralizing activity, were not able to inhibit this interaction. Taken together, these data provide direct evidence that at least three of the seven known HSV-1 glycoproteins are able to form complexes with cellular surface structures.

Antigenic cross-reaction between a varicella-zoster virus nucleocapsid protein encoded by gene 40 and a herpes simplex virus nucleocapsid protein

Human sera from varicella-zoster virus (VZV) and herpes simplex virus type 1 (HSV-1) seropositive individuals contain antibody to a 155-kilodalton (155 kDa) viral protein. In this study, we show that monoclonal antibodies (mAb10.1 and mAb1A1.4) prepared against VZV and HSV-1 proteins, respectively, reacted with nuclear antigens and recognized a 155 kDa protein in the infected cells. Immunoprecipitation of whole virions and viral nucleocapsids with these mAbs showed that the 155 kDa protein is located in VZV and HSV-1 nucleocapsids. In addition, immunofluorescence and cross-reaction experiments revealed the antigenic cross-reactivity between the VZV and HSV-1 155 kDa nucleocapsid proteins. To map the coding region of the VZV 155 kDa protein, a truncated DNA fragment from the predicted open reading frame 40 was cloned into an in vitro transcription vector (pGEM). The RNA transcribed from the inserted DNA was translated in vitro and immunoprecipitated with mAb10.1. The reactivity of the in vitro translation products with mAb10.1 indicated that the 155 kDa nucleocapsid protein is encoded by VZV gene 40. These findings demonstrated that the VZV 155 kDa nucleocapsid protein encoded by gene 40 induces humoral response which cross-reacts with both VZV and HSV.

Antibodies to recombinant HIV-1 vif, tat, and nef proteins in human sera

The prevalence of antibodies against HIV-1 regulatory proteins in sera of HIV-infected patients from different stages of disease was investigated. HIV-1 vif, tat, and nef genes were cloned in procaryotic vectors and were expressed as MS-2 fusion proteins (vif and nef) or as a non-fusion protein (tat). These recombinant proteins were employed in immunoblot experiments. The specificity of the recognition was confirmed by competition experiments and with control sera from HIV-negative patients. Analysis of 136 serum samples revealed a high percentage of antibodies against nef, irrespective of the stage of disease. Antibodies against tat were found less frequently and increased from 16% to 40% with disease progression. Vif antibodies were detected only in a low percentage in early stages of disease, but their prevalence increased to 36% and 72% with progression of disease to AIDS-related complex and AIDS. Our data suggest that the detection of antibodies against nef may represent an additional and useful marker for the diagnosis of HIV infection, whereas the detection of vif antibodies may indicate disease progression.

Orofacial herpes simplex virus infections: current concepts in the epidemiology, pathogenesis, and treatment, and disorders in which the virus may be implicated

Herpes simplex virus (HSV) is the causal agent of herpetic stomatitis, recurrent herpes labialis, and the recurrent intraoral infections seen particularly in the immunocompromised patient. HSV has also been implicated in some erythema multiforme, cranial neuropathies, Behçet's syndrome, and oral squamous carcinoma. Recent advances in understanding of HSV, epidemiology, pathogenesis, and treatment are reviewed because there have been numerous advances over the past 5 years.

Relatedness of glycoproteins expressed on the surface of simian herpes-virus virions and infected cells to specific HSV glycoproteins

The antigenic relatedness of the surface glycoprotein antigens of six herpesviruses indigenous to human and nonhuman primates was examined. Binding of anti-viral sera to viral antigens expressed on the surface of infected cells demonstrated that the surface antigens of herpes simplex virus type 1 (HSV 1), HSV 2, simian agent 8 (SA8), and Herpesvirus simiae (B virus) exhibit extensive cross-reactivity. Surface antigens of two viruses isolated from South American primates, H. saimiri 1 (HVS 1) and H. ateles 1 (HVA 1), were comparatively more virus-specific in their antigenic reactivity. Endpoint neutralization tests performed in the presence and absence of complement confirmed these results. Immunoprecipitation of viral proteins was used to identify those representing cross-reactive surface antigens. A glycoprotein of approximately 110,000-125,000 Daltons (110-125 k) was immunoprecipitated from cells infected with each of the six primate herpesvirus by antisera to each of the viruses. Using monospecific antisera, these glycoproteins were shown to be antigenically related to the gB glycoproteins of HSV. Although these glycoproteins were antigenically conserved among all six viruses, antibodies to the gB glycoproteins did not cross-neutralize heterologous viruses. A glycoprotein of approximately 60-70 k was precipitated from HSV 1, HSV 2, SA8, and B virus infected cells by antisera to each of these four viruses. These SA8 and B virus glycoproteins were shown to be antigenically related to the gD glycoproteins of HSV 1 and HSV 2 and to be involved in cross-neutralization among these viruses. Antisera to HVS 1 and HVA 1 did not recognize these gD glycoproteins nor was a glycoprotein of similar molecular weight precipitable from HVS 1 or HVA 1 infected cells by antisera to the other four viruses. Southern blot hybridizations using probes for HSV glycoprotein genes confirmed the conservation of the gB glycoproteins among all the simian viruses and of the gD gene in SA8 and B virus. A glycoprotein of approximately 75-80 k was, however, precipitated from HVS 1 and HVA 1 infected cells by antisera to either of these two viruses. In addition, at least one glycoprotein which appeared to be predominantly virus-specific in its reactivity was identified for five of the viruses.

Replication of herpes simplex virus type 1 in differentiated human promyelocytic HL-60 cells

The capability of herpes simplex virus type 1 (HSV-1), strain Angelotti (ANG), to replicate in human promyelocytic HL-60 cells treated with 1,2-tetradecanoyl-phorbol-13-acetate (TPA) and dimethyl sulfoxide (DMSO) was examined. Virus titrations and infectious center assays revealed that HSV-1 ANG replicated in nontreated HL-60 cells and in HL-60 cells treated with TPA. An abortive infection was observed in DMSO-stimulated HL-60 cells. Viral DNA synthesis was detected in nontreated and TPA-treated cells, but not in DMSO-treated cells. Analysis of HSV-1 transcripts revealed that albeit the differences in pretreatment, HL-60 cells synthesized viral immediate-early (ICP4) and early (tk and pol) RNAs, whereas a late viral transcript (gC) was almost exclusively detected in nontreated and TPA-treated HL-60 cells. In line with these observations were the results obtained from studies on viral protein synthesis. The immediate-early protein ICP4 was found in all three cell types. Early (pol), delayed-early (gB), as well as late proteins (VP 5, gC) were identified in nontreated and TPA-treated cells, but only in reduced amounts in DMSO-treated cells. These data suggest a translational block of HSV replication in DMSO-treated HL-60 cells at the level of early gene expression.

Neutralizing activity of antibodies against the major herpes simplex virus type 1 glycoproteins

The specificity and neutralizing activity of antibodies against the major herpes simplex virus type 1 (HSV-1) glycoproteins were tested in serum samples of patients with a history of HSV-1 infection. By preabsorption of sera to preparations of native and denatured HSV-1 proteins, followed by immunoblotting and microneutralization, it was shown that the majority of neutralizing antibodies are directed against denaturation-sensitive epitopes. Furthermore, preabsorption of sera to proteins of viral ts and deletion mutants revealed that antibodies specific for gB, gC, and gE had a low neutralizing activity. These results suggest a major role of anti-gD in neutralization of viral infectivity. In addition, it was shown that antibodies directed against the gB monomer were distinct from antibodies against the gB homodimers. The latter, however, did not reveal any measurable neutralizing activity.

Chronic herpes simplex virus and varicella zoster virus infection

After defining such terms as persistent and chronic infection, latency, recurrence, recrudescence, and exogenous reinfection they are applied to infections with HSV and VZV. Possible factors determining pathogenicity are discussed, and an overview is given of the wide range of illnesses and case reports ascribed to HSV and VZV infections. Various types of infection afford different diagnostic procedures. Besides virus isolation supplemented by viral antigen identification IgG antibody tests (increase in titer) may be useful. IgG subtype and IgA antibody determinations appear to be of limited value. Despite the rather large number of available tests, there are still considerable shortcomings in their ultimate significance as to the patient's disease. Thus, some new experimental approaches are mentioned.

Low incidence and high titers of antibodies to hepatitis B virus X-protein in sera of Chinese patients with hepatocellular carcinoma

Sera of patients from China with hepatocellular carcinoma (HCC) were tested for the presence of HBc/HBe- and HBx antibodies by immunoblotting using recombinant MS2 or beta gal fusion proteins as substrate. Antibodies against HBx were detected in four out of 68 HBsAg positive and in one out of three HBsAg negative sera, antibodies against HBc/HBe in 52 and two serum samples, respectively. Competition experiments in which sera were preincubated with individual viral proteins synthesized in E. coli were carried out to demonstrate the specificity of signals obtained in immunoblot analyses. In the five anti-HBx positive sera, the antibody titer against X fusion protein was higher than against core fusion protein and in one of these sera anti-x activity could be demonstrated even at a serum dilution of 1:50,000. These data indicate that X antibodies occur rarely in Chinese patients and are not serodiagnostic for HCC. The high titer of X antibodies in some patients shows that the X protein can be highly immunogenic in vivo. Induction of antibody formation may be triggered by X protein expressed from integrated viral DNA.

Frequent detection of antibodies to hepatitis B virus x-protein in acute, chronic and resolved infections

Recombinant MS2- or beta gal fusion proteins containing parts of hepatitis B virus (HBV) HBx-, HBc-, and HBs-amino acid sequences were expressed in Escherichia coli and were used to screen 96 and 60 serum samples of HBV infected and uninfected patients, respectively, for the corresponding antibodies by immunoblotting. Antibodies against HBx were detected in 20 out of 65 sera of patients with previous resolved HBV-infection, in 3 out of 7 patients with persistent infection, and in 9 out of 24 sera of patients with acute HBV infection. The specificity of the immune reaction was confirmed by competition experiments with MS2- and beta gal-HBx fusion proteins, and by the lack of HBx antibodies in the sera of uninfected patients. Hbs and HBc antibodies were detected less frequently by immunoblotting with recombinant fusion proteins than by a commercial immunoassay. Our results indicate that HBx antibodies are induced early and frequently during HBV infection suggesting that the HBx protein is an early antigenic protein expressed in vivo.

Homology of the HSV-2 "a-sequence" to cellular sequences

Bgl-II fragments of the genome of Herpes simplex virus type 2 (HSV-2) HG-52 were cloned into the vector p-Neo and were used to screen the complete HSV-2 genome for regions cross-hybridizing with the genome of HEL cells. Most extensive cross-hybridizing activity was observed with a 530 bp SstII subfragment of the viral BamHI G DNA-fragment (contained in Bgl II F), which spans the joint and the viral a-sequence. From a lambda-L47 library, a cellular 15 kb HindIII DNA fragment was subcloned in pBR 322 which contained a 1920 bp SstII subfragment having strong cross-hybridizing activity with the 530 bp Sst II fragment of HSV-2 BamHI G. Within this 1920 bp Sst II fragment the cross-hybridizing activity was confined to a 230 bp Bgl I/Hpa II subfragment. This 230 bp fragment (including the flanking sequences) was analyzed in comparison to the viral a-sequence. Sequence data revealed a (G + C) content of 66% in the cellular and 81% in the viral DNA fragment, which is mainly determined by an extremely (G + C) rich 16-fold direct repeat (DR2) at the 5'-end. The homology between both DNA-fragments varies between 56% and 79% within the L-S inversion region. Both sequences, furthermore, show homology to the human c-myc protooncogene.