[Detection of regulatory protein p16/INK4A in the dysplastic cervical squamous cell epithelium is a diagnostic tool for carcinoma prevention]

Parallel sections from 423 randomly selected blocks representing biopsies of 178 women with the diagnosis of cervical dysplasia and/or erosion were stained for p16 polypeptide. The p16/INK4A (inhibitory kinase 4) protein is a cellular division regulator, expression of which increases in the presence of oncoprotein E7, encoded by human papillomavirus (HPV). Expression of p16 protein was seen in the nuclei and cytoplasm of dysplastic squamous epithelium cells as well as in carcinoma cells. In 16.6% of erosion cases, the p16 antigen was present in the basal and suprabasal layer of the surrounding squamous epithelium revealing features of CIN I/LSIL. In CIN I/LSIL as classified by HE staining, the p16 antigen was found in 65 out of 80 (81%) cases. The p16 protein was typically seen in dysplastic basal and suprabasal cells encompassing a confluent layer in the lowest third segment of stratified epithelium. In CIN II and CIN III grouped as HSIL, the positive rate of p16 antigen presence was 95% (in 45 cases out of 47) and/or 100% (in each of 27 cases), respectively. The typical sign of p16 antigen distribution in HSIL was its staining over two thirds and/or throughout the whole dysplastic epithelium. Extensive staining for p16 antigen was registered within nuclei as well as cytoplasm of neoplastic cells in all 6 cervical squamous cell carcinomas, which were examined in many sections when being used as positive controls. Based on our experience, we consider the p16 antigen staining a helpful tool indicating dysplastic cells and estimating their extent.

Multiorgan distribution of human influenza A virus strains observed in a mouse model

Multiorgan spread and pathogenesis of influenza infection with three human influenza A viruses was studied in mice. Mouse-adapted viruses A/Dunedin/4/73(H3N2), A/Mississippi/1/85(H3N2), and A/PR/8/34(H1N1) differed considerably in virulence (p.f.u./LD(50)): 79,000 p.f.u. for Dunedin, 5,000 p.f.u. for Mississippi, and 65 p.f.u. for PR/8, which qualified Dunedin as low virulent, Mississippi as intermediate, and PR/8 as highly virulent. All three viruses were detected in lungs, heart, and thymus by cultivation and RT-PCR. Moreover, vRNA of all viruses was found in liver and spleen, of Dunedin and PR/8 also in kidneys and that of Dunedin and Mississippi in blood. Only vRNA of Dunedin was demonstrated in brain. Lung damage accompanied by histopathological changes and thymus reduction were most extensive after infection with the highly virulent virus PR/8. We assume that the ability to spread to multiple organs may be a more common property of influenza viruses in mammalian hosts than previously believed.

Immune response and cytokine production following immunization with experimental herpes simplex virus 1 (HSV-1) vaccines

Balb/c mice were immunized with the recombinant fusion protein gD1/313 (FpgD1/313 representing the ectodomain of HSV-1 gD), with the non-pathogenic ANGpath gE-del virus, with the plasmid pcDNA3.1-gD expressing full-length gD1 and with the recombinant immediate early (IE) HSV-1 protein ICP27. Specific antibodies against these antigens (as detected by ELISA) reached high titers with the exception of the DNA vaccine. High-grade protection against challenge with the virulent strain SC16 was found following immunization with the pcDNA3.1-gD plasmid and with the gE-del virus. Medium grade, but satisfactory protection developed after immunization with the FpgD1/313 and minimum grade protection was seen upon immunization with the IE/ICP27 polypeptide. A considerable response of peripheral blood cells (PBL) and splenocytes in the lymphocyte transformation test (LTT) was found in mice immunized with FpgD1/313, with the pcDNA3.1-gD plasmid and with the live ANGpathgE-del virus. For lymphocyte stimulation in vitro, the FpgD1/313 antigen was less effective than the purified gD1/313 polypeptide (cleaved off from the fusion protein); both proteins elicited higher proliferation at the 5 microg per 0.1 mL dose than at the 1 microg per 0.1 mL dose. The secretion of Th type 1 (TNF, IFN-gamma and IL-2) and Th type 2 (IL-4 and IL-6) cytokines was tested in the medium fluid of purified PBL and splenocyte cultures; their absolute values were expressed in relative indexes. The PBL from FpgD1/313 immunized mice showed increased secretion of both T(H)1 (TNF) as well as T(H)2 (IL-4) cytokines (7-10-fold, respectively). Splenocytes from FpgD1/313 immunized mice showed a significant (23-fold) increase in IL-4 production.

Efficacy of recombinant herpes simplex virus 1 glycoprotein D candidate vaccines in mice

To compare the immunogenity of the herpes simplex virus 1 (HSV-1/HHV-1) recombinant glycoprotein D (gD1), as a potential protective vaccine, Balb/c mice were immunized with either gD1/313 (the ectodomain of the gD1 fusion protein consisting of 313 amino acid residues), or the plasmid pcDNA3.1-gD (coding for a full length gD1 protein, FLgD1). A live attenuated HSV-1 (deleted in the gE gene), and a HSV-1 (strain HSZP)-infected cell extract served as positive controls, and three non-structural recombinant HSV-1 fusion proteins (ICP27, UL9/OBP and thymidine kinase--TK) were used as presumed non-protective (negative) controls. Protection tests showed that the LD50 value of the challenging infectious virus increased 90-fold in mice immunized with ICP27, but remained unchanged in other control mice immunized with TK and OBP polypeptides. A significant protection (the LD50 value of challenging virus increased 800-fold) was noted following immunization with gD1/313, while immunization with the gE-del virus and/or the gD1 DNA vaccine resulted in a more than 4,000-fold increase of the challenging virus dose killing 50% of the animals. Using ELISA, elevated antibody titers were detected following immunizations with gD1/313, gE-del virus, and/or HSV-1-infected-cell extract. In addition, all of the three non-structural proteins elicited a good humoral response (with titres ranging from 1:16,000 to 1:128,000). The lowest IgG response (1:8,000) was noted after immunization with the gD1 DNA vaccine. Peripheral blood leukocytes (PBLs) as well as splenocytes from mice immunized with gD1/313, gE-del virus, and gD1-plasmid responded in lymphocyte transformation test (LTT) to the presence of purified gD1/313 antigen. For PBLs, the most significant stimulation of thymidine incorporation was registered at a gD1/313 concentration of 5 microg/100 microl, while the splenocytes from DNA vaccine-immunized mice responded already at a concentration of 1 microg/100 microl.

Developments in herpes simplex virus vaccines: old problems and new challenges

Vaccination has remained the best method for preventing virus spread. The herpes simplex virus (HSV) candidate vaccines tested till now were mostly purified subunit vaccines and/or recombinant envelope glycoproteins (such as gB and gD). In many experiments performed in mice, guinea pigs and rabbits, clear-cut protection against acute virus challenge was demonstrated along with the reduction of the extent of latency, when established in the immunized host. The immunotherapeutic effect of herpes vaccines seems less convincing. However, introduction of new adjuvants, which shift the cytokine production of helper T-cells toward stimulation of cytotoxic T-cells (TH1 type cytokine response), reveals a promising development. Mathematical analysis proved that overall prophylactic vaccination of seronegative women, even when eliciting 40-60 % antibody response only, would reduce the frequency of genital herpes within the vaccinated population. Even when partially effective, immunotherapeutic vaccination might represent a suitable alternative of chronic chemotherapy in recurrent labial and genital herpes.

Current developments in viral DNA vaccines: shall they solve the unsolved?

This review describes the mechanisms of immune response following DNA vaccination. The efficacy of DNA vaccines in animal models is highlighted, especially in viral diseases against which no widely accepted vaccination is currently available. Emphasis is given to possible therapeutic vaccination in chronic infections due to persisting virus genomes, such as recurrent herpes (HSV-1 and HSV-2), pre-AIDS (HIV-1) and/or chronic hepatitis B (HBV). In these, the problem of introducing foreign viral DNA may not be of crucial importance, since the immunised subject is already a viral DNA (or provirus) carrier. The DNA-based immunisation strategies may overcome several problems of classical viral vaccines. Novel DNA vaccines could induce immunity against multiple viral epitopes including the conservative type common ones, which do not undergo antigenic drifts. Within the immunised host, they mimic the effect of live attenuated viral vaccines when continuously expressing the polypeptide in question. For this reason they directly stimulate the antigen-presenting cells, especially dendritic cells. The antigen encoded by plasmid elicits T helper cell activity (Th1 and Th2 type responses), primes the cytotoxic T cell memory and may induce a satisfactory humoral response. The efficacy of DNA vaccines can be improved by adding plasmids encoding immunomodulatory cytokines and/or their co-receptors.

Molecular mechanisms of virus spread and virion components as tools of virulence. A review

Despite of differences in replication strategy among virus families, some basic principles have remained similar. Analogous mechanisms govern virus entry into cells and the use of enzymes which direct the replication of the virus genome. The function of many cell surface receptors (such as glycosoaminoglycans, glycoproteins, proteins) which interact with viral capsid proteins or envelope glycoproteins has recently been elucidated. The list of cellular receptors (Table I) is still far from being final. The capsid components, similarly as the envelope glycoproteins, may form specific pocket like sites, which interact with the cell surface receptors. Neutralizing antibodies usually react with antigenic domains adjacent to the receptor binding site(s) and hamper the close contact inevitable for virion attachment. In the case of more complex viruses, such as herpes simplex virus, different viral glycoproteins interact with several cellular receptors. At progressed phase of adsorption the virions are engulfed into endocytic vesicles and the virion fusion domain(s) become(s) activated. The outer capsid components of reoviruses which participate in adsorption and fusion may get activated already in the lumen of digestive tract, i.e. before their engulfment by resorptive epithelium cells. Activation of the hydrophobic fusion domain(s) is a further important step allowing to pass through the lipid bilayer when penetrating the cell membrane in order to reach the cytosol. Activation of the virion fusion domain is accomplished by a conformation change, which occurs at acid pH (influenza virus hemagglutinin, sigma 1 protein of the reovirus particle) and/or after protease treatment. The herpes simplex virus fusion factors (gD and gH) undergo conformation changes by a pH-independent mechanism triggered due to interaction with the cell surface receptor(s) and mediated by mutual interactions with the viral envelope glycoproteins. The virion capsid or envelope components participating in the entry and membrane fusion are not the only tools of virulence. The correct function of virus coded proteins, which participate in replication of the viral genome, and/or in the supply of necessary nucleotides, may be very essential. In the case of enteroviruses, which RNA interacts with ribosomes directly, the correct configuration of the non-coding viral RNA sequence is crucial for initiation of translation occurring in the absence of the classical "cap" structure.

Leukemia-like syndrome in Balb/c mice infected with the lymphotropic gamma herpesvirus MHV-Sumava: an analogy to EBV infection

Based on our previous observation that primary infection with the murine gamma herpesvirus (MHV) isolate Sumava (MHV-SU) undergoes a lymphoproliferative phase resembling to Epstein-Barr virus (EBV) induced infectious mononucleosis (IM), we evaluated white blood cell (WBC) counts at late stages following MHV-SU infection. In consequence of intranasal inoculation with MHV-SU a leukemia-like syndrome in Balb/c mice developed. The syndrome in question was accompanied with significant splenomegaly; in the peripheral blood leukocytosis (from 8 x 10(4) to 5 x 10(5) leukocytes/microl) and a high percentage of atypical lymphocytes (60-80%) was found. Presented results are bringing further evidence for lymphoproliferative effect of MHV and point at analogic course of MHV-SU and EBV infections.

Expression of herpes simplex virus 1 glycoprotein D in prokaryotic and eukaryotic cells

Recombinant plasmids encoding either the full-length glycoprotein D (FLgD) or truncated gDs were constructed. The recombinant plasmids were expressed in Escherichia coli and BHK-21 cells. The strongest expression was obtained with the recombinant plasmid encoding a truncated gD which corresponded to the gD ectodomain. The cells transformed with this plasmid showed good exponential growth ensuring satisfactory yields of the expressed polypeptide in the form of the fusion protein. The fusion protein was biotinylated and efficiently purified. The shortest truncated gD, which contained the main continuous antigenic locus VII binding neutralization antibody and additional continuous antibody binding epitopes, still reacted with specific antibody as proven by immunoblot analysis. In addition, a shuttle vector for expression of FLgD in mammalian cells was constructed. This vector-transfected BHK-21 cells expressed gD for 40 days during 9 consecutive passages. The expression of gD began on day 2 and culminated at day 9 post transfection (p.t.).

Detection of immediate early protein ICP27/IE63 and thymidine kinase in the course of reactivation of latent herpes simplex virus 1 infection

We followed the kinetics of reactivation of latent Herpes simplex virus 1 (HSV-1) infection established in rabbits by corneal route. The corresponding trigeminal ganglia (TG) were cultured and the culture medium was examined at daily intervals for release of infectious virus. Sections from the cultured TG fragments were stained with antisera against non-structural proteins such as the immediate early (IE) protein ICP27 and the early (E) proteins thymidine kinase (TK), the large subunit of ribonucleotide reductase (RR1), the ori-binding protein OBP and with a human serum obtained from volunteers immunized with an experimental subunit HSV-1 envelope (env) vaccine containing late structural proteins gB1, gC1, gD1 and gG1 (env antiserum). By indirect immunofluorescence (IF) test, ICP27 was detected in a few neurons from day 1 post explantation (p.e.), while TK was observed in neurons from day 2 p.e. Fluorescence with the human env antiserum was seen at day 3 p.e. The RR1 and OBP antisera stained productively infected Vero cells from 3 and 4 hrs post inoculation (p.i.), respectively. However, these sera showed no IF in cultured ganglion fragments at any interval examined. Our results showed the same cascade of HSV-1 IE and E protein expression during productive infection and reactivation in vitro.

Gamma herpesviruses: pathogenesis of infection and cell signaling

Altered cell signaling is the molecular basis for cell proliferation occurring in association with several gamma herpesvirus infections. Three gamma herpesviruses, namely EBV/HHV-4, KSHV/HHV-8 and the MHV-68 (and/or MHV-72) and their unusual cell-pirated gene products are discussed in this respect. The EBV, KSHV as well as the MHV DNA may persist lifelong in an episomal form in the host carrier cells (mainly in lymphocytes but also in macrophages, in non-hornifying squamous epithelium and/or in blood vessel endothelial cells). Under conditions of extremely limited transcription, the EBV-infected cells express EBNA1 (EB nuclear antigen 1), the KSHV infected cells express LANA1 (latent nuclear antigen 1), while the MHV DNA carrier cells express the latency-associated protein M2. With the full set of latency-associated proteins expressed, EBV carrier cells synthesize additional EBNAs and at least one LMP (latent membrane protein 1). The latent KSHV carrier cells, in addition to LANA1, may express a viral cyclin, a viral Fas-DD-like ICE inhibitor protein (vFLIP) and a virus-specific transformation protein called kaposin (K12). In MHV latency with a wide expression of latency-associated proteins, the carrier cells express a LANA analogue (ORF73), the M3 protein, the K3/IE (immediate early) proteins and M11/bcl-2 homologue proteins. During the period of limited gene expression, the latency-associated proteins serve mainly for the maintenance of the latent episomal DNA (a typical example is EBNA1). In contrast, during latency with a broader spectrum gene expression, the virus-encoded products activate transcription of otherwise silenced cellular genes, which leads to the synthesis of enzymes capable of promoting not only viral but also cellular DNA replication. Thus, the latency-associated proteins block apoptosis and drive host cells towards division and immortalization. Proliferation of hemopoetic cells, which had become gamma herpesvirus DNA carriers, can be initiated and strongly enhanced in the presence of inflammatory cytokines and by virus-encoded analogues of interleukins, chemokines and IFN regulator proteins. At early stages of tumor formation, many proliferating hemopoetic and/or endothelium cells, which had became transcriptionally active under the influence of chemokines and cytokines, may not yet be infected. In contrast, at later stages of oncogenesis, the virus-encoded proteins, inducing false signaling and activating the proliferation pathways, bring the previously infected cells into full transformation burst.

The UL9 ori-binding protein of herpes simplex virus 1: its expression and localization in vero cells

The ori-binding protein (OBP), an early protein which is encoded by the herpes simples virus 1 (HSV-1) UL9 gene and initiates the replication of viral DNA, was expressed in Escherichia coli, purified on an avidin resin and used for preparation of a mouse antiserum to OBP (OBP antiserum). Expression and localization of OBP in HSV-1-infected Vero cells was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and indirect immunofluorescence test. RT-PCR revealed the presence of abundant UL9 transcripts from 3 to 12 hrs post infection (p.i). Traces of UL9 mRNA were detected already at 1.5 hr p.i. The OBP antiserum detected clumps of irregularly shaped structures in the nuclei of infected Vero cells first at 4 hrs p.i. These nuclear structures peaked at 5-6 hrs p.i. and later on (at 8-12 hrs p.i.) they changed into fine granules filling the whole nucleus.

A simple procedure for expression and purification of selected non-structural (alpha and beta) herpes simplex virus 1 (HSV-1) proteins

The expression and isolation of herpes simplex virus 1 (HSV-1) immediate early (alpha) IE63 (ICP27) and of the early (beta) thymidine kinase (Tk) polypeptides in Escherichia coli JM 109 cells transformed with the PinPoint Xa-1 (Promega) plasmid construct carrying either the HSV-1 UL54 or UL23 genes are described. The resulting biotinylated fusion protein(s) could be easily induced and were purified in appropriate amounts by means of a monomeric avidin-conjugated resin (SoftLink Soft Release Avidin Resin, Promega) provided that: (1) the exponential growth of the selected transformed cells was monitored carefully; (2) the post-induction harvest interval was properly chosen; and (3) the period for adsorption to the avidin resin suitably adjusted. The isolated protein(s), although partially digested in the case of the IE63 polypeptide, were suitable antigen(s) for immunization of various animal species. Co-purification of trace amounts of endogenous biotinylated protein(s) produced in E. coli was eliminated by shortening the duration of adsorption to the avidin resin.

Characterization of strain HSZP of herpes simplex virus type 1 (HSV1)

The genetic background of HSZP virus, an HSV1 strain with extensive passage history, was analyzed by parallel comparative sequencing of four relevant genes (UL27/gB, UL41/vhs, UL44/gC and UL53/gK) of HSZP and additional three selected viruses [strains ANGpath, strains KOS(a) and KOS(b) and the prototype strain 17]. Mutation at position 858 (His for Arg) in gB of HSZP was found to be responsible for giant cell formation (syn3gB mutation) similarly as the 855 mutation (Val for Ala) in the gB of ANGpath. No syn1gK mutations were detected in the UL53 gene either of HSZP or of ANGpath viruses. The reduced virulence of HSZP for adult mice after peripheral inoculation, similarly as that of KOS virus, seems to be related (at least in part) to numerous mutations in the gB ectodomain. Of these, two mutations located in the antigenic domain IV were the same in gBHSZP as well as in gBKOS (at amino acids 59 and 79), at least two (amino acids 313 and 553) were specific for gBKOS, while one mutation (Ser for Ala at position 108) was specific for gBHSZP. The abolished shutoff function of the HSZP virus was related to at least four out of six specific mutations seen in the vhs polypeptide (vhsHSZP) encoded by the UL41 gene, of which three (amino acids 374, 386, 392) were clustered in the semiconservative box A of vhsHSZP (the truncation of which abrogates the inhibition provided by this protein) and one mutation (at amino acid 18) was situated in the highly conservative locus I of vhsHSZP. In addition, the two vhsKOS specific mutations (amino acids 19 and 317) not found in vhsHSZP, enhanced the early host shutoff function of the vhsKOS protein. Finally, gCHSZP had two specific mutations (amino acids 137 and 147) located in the antigenic domain II of gC, which is responsible for binding of HSV1 virions to the glycosoaminoglycan (GAG) receptor. When expressed in Sf21 cells using the recombinant baculovirus system (Bac-to-Bac), gCHSZP and gCKOS showed no essential antigenic differences.

Herpes simplex virus 1 (HSV-1) strain HSZP glycoprotein B gene: comparison of mutations among strains differing in virulence

The nonpathogenic HSZP strain of HSV-1 induces large polykaryocytes due to a syn3 mutation (His for Arg at residue 858) in the C-terminal endodomain of glycoprotein B (gB) (40). We determined the nucleotide (nt) sequence of the UL27 gene specifying the gB polypeptide of HSZP (gBHSZP) and found 3 mutations in its ectodomain at aminoacids (aa) 59, 79 and 108. The ANGpath virus, which also has a syn3 mutation in the C-terminal endodomain of gB (Val for Ala at residue 855) is pathogenic for adult mice (39), but can be made nonpathogenic by replacing the gBANGpath gene by the corresponding gBKOS sequence (21). The gBANGpath had three ectodomain mutations (at aa 62, 77 and 285), while gBKOS had at least four ectomain mutations (aa 59, 79, 313, and 553). Two mutations (aa 59 and 79) in the latter, located in the variable antigenic site IV/D1 were common for gBKOS and gBHSZP. These together with the gBANGpath mutations at aa 62 and 77 create a cluster of 4 mutations in diverse region of the N-terminal part of gB (between aa 59-79), in which the gBs of pathogenic ANGpath and 17 viruses differ from the gBs of nonpathogenic HSZP and KOS viruses. The lower pathogenicity of KOS as related to gBKOS, is furthermore associated with the change of Ser to Thr at aa 313 (locus III/D2). The possibility is discussed that mutations in both above mentioned antigenic loci could result in higher immunogenicity of the corresponding antigenic epitopes, which, in turn, would contribute to the decreased virulence of HSZP and KOS viruses.

Characterization of glycoprotein C of HSZP strain of herpes simplex virus 1

Sequences of UL44 genes of strains HSZP, KOS and 17 of herpes simplex virus 1 (HSV-1) were determined and the amino acid sequences of corresponding glycoproteins (gC) were deduced. In comparison with the 17 strain, the HSZP strain showed specific changes in 3 nucleotides and in 2 amino acids (aa 139 and 147, both from Arg to Trp) in the antigenic locus LII. The change at aa 147 was situated within the GAG-binding epitope. In a similar comparison, KOS strain had changes in 3 nucleotides and 3 amino acids (aa 3, 14, and 300). The UL44 genes of HSZP and KOS strains were expressed in insect Sf-21 cells by means of the baculovirus (Bac-to-Bac) expression system. As shown by immunoblot analysis, both the recombinant baculoviruses (B1-HSZP and B6-KOS) expressed a glycosylated gC, the M(r) of which (116 K) was lower than that of gC synthesized in Vero cells (129 K) infected with strains HSZP or KOS. In addition, smaller gC-specific proteins (of apparent M(r) of 50-58 K and 98 K) corresponding to a non-glycosylated precursor polypeptide and/or incomplete forms of the partially glycosylated gC were found. When Balb/c mice were immunized with Sf-21 cells expressing gC, the recombinant gC-HSZP represented a more efficient immunogen possibly due to its stronger expression in these cells. The corresponding gC-HSZP antiserum reacted in enzyme-linked immunosorbent assay (ELISA) equally well with HSZP and KOS virion antigens and neutralized HSZP strain at a low titer. Both gC-HSZP and gC-KOS antisera detected the homologous as well as the heterologous gC antigens in Vero cells regardless whether infected with strains HSZP, KOS or 17, revealing the presence of gC from 6 to 16 hrs post infection (p.i.) in the cytoplasm, on the nuclear membrane and at the cell surface.

Early expression of herpes simplex virus (HSV) proteins and reactivation of latent infection

During the last decade, new data accumulated describing the early events during herpes simplex virus 1 (HSV-1) replication occurring before capsid formation and virion envelopment. The HSV virion carries its own specific transcription initiation factor (alpha-TIF), which functions together with other components of the cellular transcriptase complex to mediate virus-specific immediate early (IE) transcription. The virus-coded IE proteins are the transactivator and regulatory elements modulating early transcription and subsequent translation of nonstructural virus-coded proteins needed mainly for viral DNA synthesis and for the supply of corresponding nucleoside components. They also cooperate at the late transcription and translation of the virion (capsid, tegument and envelope) proteins. In addition, the transactivator IE proteins down-regulate their own transcription, while others facilitate viral mRNA processing or interfere with the presentation of newly synthesized virus antigens. Establishment of latency is closely related to the transcription of a separate category of transcripts, termed latency-associated (LAT). Formation of LATs occurs mainly in nondividing neurons which are metabolically less active and express lower levels of cellular transcription factors (nonpermissive cells). Expression of the stable non-spliced (2 kb), and especially of stable spliced (1.5 and 1.45 kb) LATs is a prerequisite for HSV reactivation. Different HSV genomes (from various HSV strains) do not undergo IE transcription at the same rate. Restricted IE transcription and the absence of viral DNA synthesis favors LAT formation and persistence of the silenced genome. Uneven levels of LAT expression and differences in the metabolic state of carrier neurons influence the reactivation competence. Under artificial or natural activation conditions, sufficient amounts of IE transactivator proteins and proteins promoting nucleoside metabolism are synthesized even in the absence of the viral alpha-TIF facilitating reactivation.

Increased neoplasm development due to immunosuppressive treatment with FK-506 in BALB/C mice persistently infected with the mouse herpesvirus (MHV-72)

BALB/c mice were infected with the lymphotropic mouse gammaherpesvirus (MHV-72). At late (7-12 months) post-infection intervals the latent virus was detected in the cells of lymphatic system (peripheral blood, lymphocytes and macrophages, thymocytes, lymph nodes, bone marrow, and peritoneal macrophages,) and in the spleen, lungs, liver, and kidney by cocultivation as well as by explantation. The MHV-72 infected mice, in which latency had been established, were treated with the immunosuppressive (IS) drug FK-506 (2 mg/kg/mouse for 30 days). This treatment increased the probability of virus reactivation by over two-fold. During the post-treatment observation period of 19 months, the incidence of lymphomas and the development of MHV-related lymphoproliferative and hemoblastic disorders raised to nearly five-fold in the drug treated mice as compared to untreated animals.

Glycoprotein K of herpes simplex virus: a transmembrane protein encoded by the UL53 gene which regulates membrane fusion

Glycoprotein K (gK) encoded by the UL53 gene is the ninth out of eleven HSV glycoproteins (gps). The precursor gK (pgK) is a transmembrane protein with four hydrophobic domains, which consists of 338 amino acids. The UL53 gene has two initiation codons: the upper overlaps with the UL52 ORF, while the lower is located 55 codons downstream and specifies a truncated precursor of the gK polypeptide. The UL53 gene and the upstream located UL52 gene have a common polyadenylation signal downstream from the UL53 stop codon so that the UL53 mRNA is completely nested within the UL52 transcript. The syn1 mutations in several KOSsyn mutants and in the MPsyn virus, which had been fine mapped to DNA coordinates 0.735-0.740, were later on located to the UL53 gene, especially to its portion which specifies the first 120 amino acids (aa) from the N-terminus (most frequently residue 40) and to a less precisely defined locus between aa 301-310 (close to the C-terminus). Point mutations in the N-terminal ectodomain of gK, which are related to syn formation, impair the putative ability of this region to down-regulate membrane fusion. The two N-glycosylated mannose core oligosaccharides are attached to the Asn residues of the gK polypeptide at positions 48 and 58, respectively. In infected cells, gK is localized mainly in the nuclear and endoplasmic reticulum (ER) membranes. It is not clear, whether gK becomes incorporated into the envelope of mature HSV particles. Studies with the insertion/deletion gK mutants showed the importance of gK for capsid envelopment, for the transportation and egress or virions from infected cells. It seems that gK has an essential role in virion egress, even though this glycoprotein acts in accord with gH and with another membrane protein encoded by the UL20 gene.

Interference of the low-pH inactivated herpes simplex virus type 1 (HSV-1) strain HSZP with the early shutoff function of superinfecting HSV-1 strain KOS

In former studies, we described that the HSZP strain of herpes simplex virus type 1 (HSV-1) was defective with respect to the early shutoff of host protein synthesis but was effective at interfering with the early shutoff function of the HSV-1 strain KOS, even when heat-inactivated or neutralized by antibody. However, the HSZP strain failed to interfere when inactivated with zinc ions or purified from cells treated with 2-deoxy-D-glucose. In this study, we provide evidence that the ability of the purified low-pH inactivated (citrate buffer, pH 3.0) and gel-filtered (Sephadex G-25) HSZP virions to adsorb host cells was not significantly affected. However, their ability to induce interference with the early shutoff function of the superinfecting HSV-1 strain KOS was restricted. In comparison with native virus, up to eight times more low-pH inactivated HSZP virions were needed to interfere with the shutoff by strain KOS. The interference was not due to exclusion of strain KOS by HSZP at the level of adsorption and/or penetration. The restriction was partially overcome by treatment of the cells with polyethylene glycol after adsorption of the low-pH inactivated HSZP virions. This observation indicates that the direct fusion of the virion envelope of low-pH inactivated HSZP with the plasma cell membrane was predominantly hampered.

The role of herpes simplex virus glycoproteins in the virus replication cycle

At least nine of the eleven herpes simplex virus (HSV) glycoproteins so far known have been widely characterised as regards their role in the virus replication cycle. During early virus-to-cell adsorption ("adsorption"), glycoprotein C (gC) interacts with the glycosoaminoglycan (GAG) heparan sulphate (HS), located on the cell membrane surface. This interaction is labile until other glycoproteins such as B and D (gB and gD) begin to participate in the entry process. gB also harbours a site for interaction with GAGs, while gD provides a stabile attachment to cellular receptors ("receptors") such as the herpesvirus entry mediator (HVEM). Late adsorption is associated with a conformation change of gD occurring after the receptor binding, a step followed by interaction of gD with the gH/gL heterodimer (complex). Fusion domains of the gH/gL complex and gB enable the pH-independent virus-into-cell penetration ("penetration"). The gE/gI complex and gM interact with the receptors at cell junctions in order to facilitate cell-to-cell spread of the virus along the basolateral surface of polarised cells and/or a similar intercellular spread in nonpolarised cells by avoiding virion release, gK, the only so far known HSV-coded glycoprotein which is not incorporated into virions, plays an essential role in the virus capsid envelopment at the nuclear membrane and in the virion transport to the cell surface. Unusually large polykaryocytes arise due to mutations in syn (syncytium) loci of the viral genome, which were mapped to UL53 (syn1) and UL27 (syn3) genes coding for gK and gB, respectively, while the genes UL20 and UL24 (both syn5) code for nonglycosylated cell membrane-associated proteins ("membrane proteins"). The products of nonmutated syn genes either downregulate the fusion of plasma membranes of infected cells ("membrane fusion") or protect them from undesirable fusion events.

Syn strains HSZP and ANGpath [correction of ANG] of herpes simplex virus type 1 do not contain mutations in the regions of UL53 gene relevant to syncytium formation

Parallel sequencing of UL53 gene of four strains of herpes simplex virus type 1 (HSV-1), two of which (HSZP and ANGpath) were of the syn phenotype while another two (KOS and 17) were of the non-syn phenotype, showed in three strains amino acid mutations unrelated to the already described syn1 glycoprotein K (gK) mutations (Dolter et al., 1994). The only mutations which altered encoded amino acids were found in strains HSZP (Gln to Arg at position 198) and ANGpath (Val to Ile at position 137). Both mutations were localised outside of the two mutation clusters suspected for affecting syncytium formation. In addition, a CG/GC variation was found at positions 245-246 and 669-670. These compressions affected three codons altering amino acids (aa) 82 (Cys or Ser), 223 (Me or Ile) and 224 (Leu or Val), respectively.

Herpes simplex virus type 1 (HSV-1) strain HSZP host shutoff gene: nucleotide sequence and comparison with HSV-1 strains differing in early shutoff of host protein synthesis

The UL41 gene of the HSZP strain of herpes simplex virus type 1 (HSV-1) defective with respect to the early shutoff of host protein synthesis was sequenced and compared with the corresponding HSV-1 strain KOS and 17 gene sequences. In comparison with strain 17, nine mutations (base changes) were HSZP specific, five KOS specific and four were common for both strains. Nine mutations caused codon changes. Three of these mapped to the nonconserved regions and the others to the conserved regions of the functional map of UL41 gene. One KOS specific mutation mapped to the region responsible for the binding of the virion host shutoff (vhs) protein to the alpha-transinducing factor (VP16). The possible relationship between mutations and host shutoff function is discussed. The nucleotide sequence data of the UL41 gene of HSZP and KOS have been submitted to the Genbank nucleotide database and have been assigned the accession numbers Z72337 and Z72338.

Chronic infection of Balb/c mice with murine herpesvirus 72 is associated with neoplasm development

One hundred Balb/c mice were infected with murine herpesvirus strain 72 (MHV-72) and observed for 2.5 years for neoplasm development and virus presence in tumour as well as non-tumour tissues. Out of 13 neoplasm-bearing mice the virus was recovered from solid tumours (one lymphoma, two non-differentiated lymphoblastomas and two fibrosarcomas) of five mice and from the spleen of one mouse with lymphatic leukemia. The virus persisted frequently also in various organs of the neoplasm-bearing mice.

The syn3 strain HSZP of herpes simplex virus type 1 (HSV-1) is not pathogenic for mice and shows limited neural spread

Strain HSZP of the herpes simplex virus type 1 (HSV-1) forms large giant cells in vitro. This property was found associated with a mutation that alters the codon CGC (in the strain KOS or 17 sequence) to CAC (in the HSZP sequence), changing the amino acid 857 from arginine to histidine in the cytoplasmic domain of the glycoprotein B (gB) polypeptide chain. Giant cell formation by ANGpath was attributed to a mutation that alters the codon GCC (in KOS and strain 17 sequences) to GTC (in ANGpath sequence) changing the amino acid 854 in the same (syn3) region of the gB molecule. In contrast to the ANGpath virus, which is pathogenic (1 LD50 < 1 x 10(4) PFU) for adult DBA/2 mice after peripheral inoculation, strain HSZP was never found to be lethal for adult mice. Whereas ANGpath-infected mice which survived acute infection frequently (79%) developed latency in the regional sensory ganglion (as proved by virus reactivation during explantation), latent HSZP reactivated in ganglion culture at a considerably reduced rate (21%). Only 10-day-old DBA/2 mice were sensitive to HSZP infection. In these, HSZP spread from the site of peripheral administration mainly by hematogenous route. The neural spread of HSZP in suckling DBA/2 mice was manifested by the involvement of vegetative neurons in the wall of the small intestine and in the retroperitoneal vegetative ganglia. We conclude that HSZP, a polykaryocyte-forming strain with a mutation in the syn3 region II, shows limited neuroinvasity for mice after peripheral administration.

Effect of immunosuppression on Balb/c mice infected with murine herpesvirus

Balb/c mice were infected with murine herpesvirus (MHV-72) and subjected to immunosuppression (IS) with the antibiotic FK506 either during the acute or chronic phase of infection. Attempts to detect virus in various organs of immunosuppressed and non-immunosuppressed mice at different time interval were made. In the mice immunosuppressed on days 3-23 p.i. of the acute phase of infection virus was detected in various tested organs and tissues at 2.0 times higher rate than those of control mice. At later intervals of the acute phase of infection (56-84 days p.i.) virus was still recovered in bone marrow and lymph nodes peritoneal cells of immunosuppressed mice, but not in those of control animals. In the chronically infected mice immunosuppressed on days 290-320 p.i., the virus was detected in lungs, thymus, bone marrow, spleen and peritoneal cells at 3.5 times higher rate than in those of control mice.

Determination of the DNA target sequence of poorly reactivable strain HSZP of herpes simplex virus type 1 by polymerase chain reaction

HSZP strain of herpes simplex virus type 1 (HSV-1)-unlike strains KOS, SC16 and ANGpath-established latency in the homolateral trigeminal ganglion of mice at a limited rate (21%) when tested by reactivation of latent virus in culture. If a nested polymerase chain reaction (PCR) for virus DNA detection was used, the positivity rate was 63-100%. The detection rate of HSZP DNA in acutely infected gangla did not differ from that of SC16 DNA provided that the sensitivity of PCR was below 20 pg of HSZP DNA per 0.5 microgram of total ganglionic DNA. The nested PCR assessed at least 200 fg of HSZP DNA per 0.5 microgram of ganglionic DNA.

Typing of human herpesvirus-6 DNA by restriction endonuclease cleavage of the polymerase chain reaction product

A 591 bp portion of the HindIII H (pZVH14) fragment of human herpesvirus-6 (HHV-6) strains GS (type A) and R-147 (type B) DNA was amplified by the polymerase chain reaction (PCR) using specific primers. While AluI cleaved the amplified DNA of both types of HHV-6, EcoRV cut the type A but not the type B DNA; vice versa, HaeIII cleaved the type B but not the type A DNA.

Detection of herpes simplex virus DNA by polymerase chain reaction in the cerebrospinal fluid of patients with viral meningoencephalitis using primers for the glycoprotein D gene

A novel set of primers for polymerase chain reaction (PCR) which amplified the portion of US6 sequence coding for the main type-common neutralizing epitope of glycoprotein D (gD) was used for detection of herpes simplex virus (HSV) DNA in 44 cerebrospinal fluid (CSF) samples from 29 patients with clinical symptoms of viral meningitis or meningoencephalitis. The primers in question amplified the DNA of 9 out of 10 low-passage HSV-1 isolates and of 5 out of 10 HSV-2 low-passage isolates as well as the DNA of all laboratory strains examined when tested in the supernatant fluid of infected cells cultures. The PCR was positive in 5 CSF samples (taken on days 2, 4, 8, 10 and 56 after the onset of symptoms, but not later than day 8 after starting acyclovir (ACV) therapy) obtained from 4 patients with intrathecal antibody response. The PCR was repeatedly negative in CSF of 15 patients who had antibodies to HSV in serum and CSF, but did not show intrathecal antibody production. It was also negative in 10 patients who had no HSV antibodies in CSF. Our results confirmed that positive PCR for HSV DNA in the CSF is an indication for starting and/or continuing ACV therapy even in the absence of classical symptoms of HSV encephalitis.

Herpes simplex virus type 1 envelope subunit vaccine not only protects against lethal virus challenge, but also may restrict latency and virus reactivation

A subunit vaccine containing the main antigenic components of herpes simplex virus 1 (HSV-1) was tested in Balb/c mice and albino rabbits. The mice were completely protected against challenge with 10 LD50 of the highly pathogenic SC16 strain given by intraperitoneal (ip) route when immunized with 1000 antigen units (ELISA) corresponding to 110 micrograms of protein. The animals were protected against lethal disease when immunized with 1-33 micrograms of protein per dose. Immunization of rabbits with 3000 antigen units prior to inoculation of strain Kupka into right scarified cornea limited the establishment of latency in the trigeminal ganglia. Both the number of animals in which latency had been established as well as the number of homolateral sensory ganglion cells which had become virus carriers were reduced. However, the effect of immunization was less striking at preventing HSV reactivation in rabbits vaccinated after infection. When shedding of reactivated HSV was elicited by repeated epinephrine iontophoresis to cornea, there was no quantitative difference between the immunized and mock-immunized groups, only the period between stimulation and the onset of virus shedding was prolonged in immunized rabbits (from 3.6 to 5.6 days, p < 0.05). But if the corneas were stimulated by a single iontophoresis procedure, the duration of virus shedding was significantly reduced from 5.6 days in the mock-immunized rabbits to 1.7 days in the immunized ones (p < 0.025). In the latter experiment, the total number of positive swabs during 14 days of the post-stimulation period was higher in the mock-immunized animals (31 of 171, 18.1%) than in the immunized ones (12 of 162, 7.4%; p < 0.025).

Low-incidence latent infection with variant B or roseola type human herpesvirus 6 in leukocytes of healthy adults

Nested primer-based polymerase chain reaction was employed to determine the frequency of latent infection with human herpesvirus 6 (HHV-6) among healthy adults from Bratislava, Slovak Republic. A 592-bp region, upstream from the gene encoding the putative large tegument protein of HHV-6, was amplified from DNA extracted from peripheral blood mononuclear cells (PBMC) of only one of 29 seropositive adults, suggesting that as few as 1 in 10(5) PBMC may be infected with the virus. Direct sequencing of the 592-bp fragment indicated that the virus harbored by the seropositive Slovak subject (designated B38) differed by only 3 nucleotides from an HHV-6 variant B strain (R-147) isolated from an American infant with a roseola-like illness and by 32 bases from the variant A strain GS isolated from a patient with lymphadenopathy (5.4% sequence divergence). None of these strains had a deoxyadenosine at base position 1251, when compared to the published sequence of strain GS clone pZVH14. Although this discrepancy did not affect the large tegument protein gene, it altered the predicted amino acid sequences of two putative proteins coded by open-reading frames 1 and 2 (ORF 1 and ORF 2) located upstream from this gene.

Regions US6 and US7 of herpes simplex virus type 1 DNA encoding glycoproteins D and I may influence neuroinvasivity

Recombinants were prepared by replacing a 1931 bp region of the BamHI J fragment (0.906-0.920) of the pathogenic ANGpath DNA-coding for glycoprotein D (gD) and a part of glycoprotein I (gI)--by the corresponding sequence of nonpathogenic KOS DNA (Kaerner et al., 1991) and tested in DBA/2 mice. The strain ANGpath and the control recombinant ANGpath/gD-gIpath, prepared by back transfer of the given ANGpath DNA fragment into ANGpath/gD-gIdellacZ+ DNA, were pathogenic after intraperitoneal inoculation. In contrast, mice infected with the strain KOS and the low-pathogenic recombinant ANGpath/gD-gIKOS survived peripheral virus administration. Both the strain KOS and the low-pathogenic recombinant ANDpath/gD-gIKOS spread by bloodstream to spleen, liver and adrenal glands but did not multiply in spinal cord. Nevertheless, the antigen of low-pathogenic recombinant ANGpath/gD-gIKOS was found in retroperitoneal vegetative nerves and ganglia. On the other hand, the strain ANGpath and the pathogenic recombinant ANGpath/gD-gIpath multiplied in cerebrospinal nerves and spinal cord causing typical hind leg paralysis.

High serum antibody titers to human herpesvirus-6 in Melanesian population

IgG antibodies to human herpesvirus-6 were found by indirect immunofluorescence in the sera of 29 out of 45 tested healthy adults from Bratislava, and in 33 out of 49 healthy Melanesians from Solomon Islands and Papua New Guinea. Although antibody seropositivity was similar in both population groups (64.5% and 67.4%, respectively), the geometric mean titer was significantly higher in the sera of Melanesians (p < 0.0001).

Replacement of glycoprotein B gene in the herpes simplex virus type 1 strain ANGpath DNA by that originating from nonpathogenic strain KOS reduces the pathogenicity of recombinant virus

Herpes simplex virus type-1 (HSV-1) strain ANGpath and its recombinants, in which the 8.1 kbp BamHI G restriction fragment (0.345-0.399) containing the glycoprotein B (gBpath) gene (UL27) or its subfragments-coding either for cytoplasmic or surface domains of gB-had been replaced with the corresponding fragments from nonpathogenic KOS virus DNA (gBKOS), were tested for their pathogenicity for DBA/2 mice and rabbits. The recombinant ANGpath/B6KOS prepared by transferring the 2.7 kbp SstI-SstI subfragment (0.351-0.368) of the BamHI GKOS fragment still had the original sequence of ANGpath DNA coding for the syn3 marker in the cytoplasmic domain of gB and was pathogenic for mice as well as for rabbits. Virological and immunohistological studies in DBA/2 mice infected with the latter pathogenic recombinant and with ANGpath showed the presence of infectious virus and viral antigen at inoculation site (epidermis, subcutaneous connective tissue and striated muscle in the area of right lip), in homolateral trigeminal nerve and ganglion, brain stem, midbrain, thalamic and hypothalamic nuclei. In contrast, nonpathogenic recombinants ANGpath/syn+B6KOS (prepared by transferring the whole BamHI GKOS fragment) and ANGpath/syn+KOS (prepared by transferring the 0.8 kbp BamHI-SstI subfragment of the BamHI GKOS fragment) showed limited haematogenous and neural spread, but no evidence of replication in CNS; thus, their behaviour resembled that of the wild type strain KOS. The recombinant ANGpath/syn+KOS, which was not pathogenic for mice, still remained pathogenic for rabbits, a phenomenon indicating the presence of an additional locus in the gB molecule participating on virulence. Sequencing the 1478 bp SstI-SstI subfragment of the BamHI G(path) fragment (nt 53,348-54,826 of UL segment) showed the presence of at least 3 mutations as compared to the KOS sequence, from which the change of cytosine to thymine at nt 54,251 altered the codon for arginine to that for histidine (amino acid 515) in the gB polypeptide chain.

[Herpesvirus research at the Virology Institute of the Slovak Academy of Science]

Research of the herpes virus (HSV) in the Institute of Virology of the Slovak Academy of Sciences in Bratislava has achieved some interesting results. An original technique has been elaborated for the purification of HSV visions and the separation of envelopes and naked particles. Studies of the properties of the HSZP strain of HSV type 1, adapted by us, showed that this virus did not only fail to shut off host cell proteosynthesis but also interfered with this ability of the KOS strain. Interesting results were achieved in elaborating the experimental pathogenesis of HSV and pseudorabies virus, especially concerning their neural spread. Important was the discovery of latent infection established with pseudorabies virus and the detection of spontaneously nonreactivating HSV DNA sequences in the nervous system of experimental animals and in man. A new herpesvirus was isolated from rodents at large, distinct from the so far known mouse CMV. This virus proved to be of interest because of its peculiar pathogenesis (similar to that of alpha herpes viruses) and DNA structure (similar to that of gamma herpes viruses). The preparation of a subunit vaccine using primary quail embryo cells (along with the introduction of domestic acyclovir) opens up some perspectives for the suppression of recurrent herpes virus infections in man. The testing of HSV-1 deletion mutants aims at elucidating the role of individual genes and their products in the pathogenetic process. (Ref. 54.)

DNA regions and genes determining the virulence of herpes simplex virus

The outcome of virus-host interaction after peripheral inoculation of herpes simplex virus (HSV) depends on virus replication at the portal of entry, the ability of the virus to invade nerve endings and capillary endothelium cells and, the rate of virus replication in neurons and nonneural cells of the nervous system. Functions involved are the activity of viral thymidine kinase, DNA polymerase, immediate early transactivator proteins, the transcription initiation protein, the envelope protein(s) governing virus penetration, syncytium formation and natural killing of infected cells as well as some other regulatory DNA sequences.

Herpes simplex virus type 1 (HSV-1) HSZP interferes also after antibody neutralization with early shutoff of host protein synthesis induced by HSV-1 KOS

The HSZP strain of herpes simplex virus type 1 (HSV-1) is defective with respect to the early shutoff of host protein synthesis. However, in superinfection experiments using Vero cells, the HSZP strain was effective, even after neutralization by antibody, at interfering with the early shutoff function of the HSV-1 KOS strain. Evidence was given that the observed interference was not due to exclusion of the KOS by HSZP at the level of adsorption or penetration. The neutralized KOS strain failed to induce early shutoff of host protein synthesis.

Pathogenicity and latency competence for rabbits of the herpes simplex virus type 1 ANGpath gC and gE defective mutants

A total of 139 rabbits was infected to the right scarified cornea with HSV type 1 strains Kupka, ANG, ANGpath and their gE defective (ANGpathI2-4), gC defective (ANGpathgC18), gC/gE negative (ANGpathCI-8) and gC/ICP4 deletion (ANGpathY1) mutants. Strains ANG, ANGpath, ANGpathgC18 and ANGpathY1 were, in contrast to the two gE negative mutants, highly lethal, but 79% of rabbits infected with the non-encephalitogenic Kupka strain survived. Strain Kupka and strain ANGpath gE-negative mutants I2-4 and gCI-8 were tested for their latency competence. While Kupka established latency in the homolateral trigeminal ganglia from 80% of infected rabbits, I2-4 did so in one of 10 animals only, and the gC/gE mutant gCI-8 was not harboured in any of infected animals in an inducible form. Significant correlation was found between shedding into the culture fluid of reactivated virus from the explanted ganglion and brain stem fragments at one hand and the presence of the viral DNA in these organs on the other hand as judged by spot blot hybridization with the HSV-1 strain 17 Kpn I fragments h and i to DNA extracts prepared from these organs. Hybridizations were predominantly negative with the DNA from the corresponding non-cultured organs, except in a few cases of non-cultured ganglion and brain stem from rabbits previously infected with the gE deletion mutants which displayed positive hybridization, although no virus reactivation could be observed in corresponding explants.

Immunoprecipitation of herpes simplex virus polypeptides with human sera is related to their ELISA titre

Out of 485 human sera tested by neutralization and enzyme immunoassay 13 were negative in both tests, while a positive correlation was found in 457 samples (94.3%). The rest of sera (3.2%) showed discordant results. Selected sera were examined, in addition, by Western blot and immunoprecipitation assays with the aim to analyse the precipitation profile of discordant sera and correlate the ELISA titre with the precipitation profiles. High titre sera precipitated the main glycoproteins (gC, gB, gE, gD), the capsid polypeptides (VP 5, VP 19, VP 21, VP 22) and several other structural and nonstructural proteins. The ability of sera to precipitate viral structural proteins was related to their ELISA titre rather than to their neutralizing activity.

Type-common and type-specific monoclonal antibodies to herpes simplex virus types 1 and 2

Seventeen monoclonal antibodies (Mabs) reacting specifically with the cells infected with herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) were characterized by a variety of immunological tests such as radioimmunoprecipitation, immunoblotting and virus-neutralization. The majority of Mabs was directed against glycoprotein B (anti-gB), six reacted with glycoprotein C (anti-gC) and one with glycoprotein G (anti-gG). Six anti-gB Mabs reacted with both types of HSV (anti-gB-1,2), two anti-gB and all the six anti-gC Mabs have been specific for HSV-1 (anti-gB-1 and anti-gC-1). The remaining two anti-gB Mabs and the anti-gG have been specific to HSV-2 (anti-gB-2 and anti-gG). Only three out of the seventeen examined Mabs neutralized the virus.

Spread of herpes simplex virus (HSV) strains SC16, ANG, ANGpath and its glyC minus and GlyE minus mutants in DBA-2 mice

Herpes simplex virus type 1 (HSV-1) strains SC16, ANG, its pathogenic variant ANGpath and the mutants ANG-pathgC18 glycoprotein C (glyC) negative and ANGpathI2-4 (glyE negative) were compared for their ability to spread in DBA-2 mice after peripheral inoculation. Virus infectivity assay in 9 organs at days 2, 3, 4, 5, 6, and 10 post-infection (p.i.) and morphologic examinations (immunofluorescence, PAP staining) showed the following: SC16, ANG, and ANGpath spread first (days 2-3 p.i.) by haematogenic route to spleen, liver, and adrenal gland. Since day 4 the invasion of the vegetative and peripheral nervous system took place in SC16 and ANGpath-infected mice, followed by virus spread to the spinal cord and brain stem. In ANG-infected mice the invasion of peripheral nervous system was minimal although both ANG as well as ANGpath spread along the axons. In ANG pathC18-infected mice a relatively prolonged viraemic phase (days 2-4 p.i.) represented with foci of virus antigen-containing cells in spleen, liver, and mesenterial connective tissue was accompanied with a low grade invasion of the peripheral nervous system (days 3-4 p.i.). No spread by any route of ANGpathI2-4 was observed after intraperitoneal inoculation. When comparing ANGpath and SC16, the latter seemed slightly more lethal, since ANGpath killed 67.2% of DBA-2 mice which were given 2 X 10(6) PFU/0.1 ml by i.p. route as compared to the 100% lethality of SC16-infected animals.

Detection of viral DNA and activation of latent herpes simplex virus in the rabbit neural tissue

Both trigeminal ganglia, brain stem, and cornea from rabbits with established latent herpes simplex virus type 1 (HSV-1) infection were examined by explantation and by spot blot hybridization using strain 17 Kpn I fragments i, d, and h and the DNA extracted from above mentioned tissues. Correlation between positive hybridization and reactivation of infectious virus in the cultured explants was documented by enhanced hybridization with the DNA extracts from explanted ganglion samples. In addition, we found positive hybridization in some noncultured ganglion and brain stem samples which did not yield infectious virus by explantation. Keeping in mind the pitfalls of false positive hybridization, the results may indicate during latency the presence in neural tissues of HSV DNA sequences which did not spontaneously reactivate in culture.

Cytoplasmic islet cell antibodies in children with type I diabetes

In a group of 72 type I juvenile diabetics we investigated the prevalence of islet cell antibodies (ICA). Their occurrence rate was followed up over 1-3 years. In 66 patients also neutralizing antibodies and IgM antibodies to Coxsackie B viruses were determined. ICA positivity was recorded in 21 out of 38 Coxsackie positive diabetics (55%), compared to 13 out of 28 Coxsackie negative diabetics (46%). ICA were found in a total of 73% of diabetic patients. The postinitial course of diabetes, assessed according to partial remissions, did not differ substantially between ICA positive and ICA negative patients. ICA persisted over a longer period of time in children who had suffered from Coxsackie B virus infection than in children who had not experienced this virus infection (p less than 0.05). The concurrent action of Coxsackie B virus infection before the manifestation of diabetes may contribute to the heterogeneity of autoimmune processes in some juvenile diabetics.

Herpes simplex virus DNA in the brain of psychotic patients

Herpes simplex virus (HSV) DNA was found by spot blot hybridization in the right nc. amygdalae of 3 out 10 patients who underwent curative stereotactic surgery for severe mental retardation with aggressive behavior and/or paranoic schizophrenia. Of these, 6 were also tested for the presence of CMV DNA sequences with negative results. Biopsy specimens from nc. amygdalae of another 7 psychotic patients were cultured in vitro but no virus was isolated.

A simple novel procedure for preparation of herpes simplex virus subunit vaccine

A simple procedure for preparation of herpes simplex virus type 1 (HSV-1) subunit vaccine is described. The method is based on treatment of virus-infected cells with a nonionic detergent, removal of cell nuclei by low speed centrifugation, separation of viral nucleocapsids by high speed centrifugation through a sucrose cushion and, finally, precipitation of viral and cellular glycoproteins and proteins with ammonium sulphate (AS). Unlike to acetone precipitation, affinity chromatography on lectins or hydroxylapatite chromatography, AS precipitation repeatedly yielded the best and most reliable results as judged by relative protein content, antigenicity and immunogenicity of the final vaccine product.

Herpes simplex virus antibodies in the cerebrospinal fluid of schizophrenic patients

Antibodies to herpes simplex virus type 1 (HSV-1) were tested in the cerebrospinal fluid (CSF) of 262 schizophrenic patients by virus neutralization test (VNT) and enzyme-linked immunosorbent assay (ELISA). While VNT in the presence of complement revealed antibodies to HSV-1 in 18.3% of samples, ELISA was positive in 61.2% of cases; both tests were positive in 42 samples (16%).