Molecular and immunological evidence of oral Treponema in the human brain and their association with Alzheimer's disease.

The purpose of this investigation was to use molecular and immunological techniques to determine whether oral Treponema infected the human brain. Pieces of frontal lobe cortex from 34 subjects were analyzed with species-specific PCR and monoclonal antibodies. PCR detected Treponema in 14/16 Alzheimer's disease (AD) and 4/18 non-AD donors (P < 0.001), and AD specimens had more Treponema species than controls (P < 0.001). PCR also detected Treponema in trigeminal ganglia from three AD and two control donors. Cortex from 15/16 AD subjects and 6/18 controls contained Treponema pectinovorum and/or Treponema socranskii species-specific antigens (P < 0.01). T. pectinovorum and/or T. socranskii antigens were also found in trigeminal ganglia and pons from four embalmed cadavers, and 2/4 cadavers also had Treponema in the hippocampus. These findings suggest that oral Treponema may infect the brain via branches of the trigeminal nerve.

Prominence of the herpes simplex virus latency-associated transcript in trigeminal ganglia from seropositive humans.

Although herpes simplex virus type 1 (HSV-1) is known to reside latently in trigeminal ganglia between episodes of reactivation, the mechanisms involved in restricting the virus to this state are not understood. Using in situ nucleic acid hybridization methods, we show that there is HSV-encoded RNA in ganglion cells from 10 of 12 seropositive and zero of three seronegative patients studied at autopsy. Transcripts mapping to the region encoding the immediate-early polypeptide ICPO and the latency-associated transcript (LAT) were detected in the nuclei of these neurons. No other region of the HSV-1 genome was found to be expressed. When carefully defined probes were used to identify the transcripts, RNA corresponding to the LAT and, rarely, to ICPO was found. These results suggest that HSV-1 latency is an active process and that the LAT may be involved in regulating viral genetic expression.

Evidence that the gene for herpes simplex virus type 1 DNA polymerase accounts for the capacity of an intertypic recombinant to spread from eye to central nervous system.

HSV-1(17) replicates 100-fold more efficiently than HSV-2(186) within trigeminal ganglia following ocular infection. In order to identify the nucleotide sequences responsible for the differences in the capacity of the two HSV strains to grow within the peripheral nervous system, an intertypic recombinant was generated by infecting neuroblastoma cells with HSV-2(186) and a HSV strain possessing nucleotide sequences from HSV-1(17). The genome of the intertypic recombinant was composed entirely of HSV-2(186) DNA except for 2.0 kb of HSV-1(17) DNA positioned between m.u. 0.413 and 0.426. Following corneal infection of mice, the intertypic recombinant grew to higher titers in both ocular tissues and trigeminal ganglia than did the HSV-2 parent. Most significantly, the intertypic recombinant could spread into the brain from the trigeminal ganglion and kill the host whereas mice inoculated with the HSV-2(186) parent survived infection. The 2.0 kb of HSV-1(17) DNA inserted into the genome of the intertypic recombinant encodes the 5' terminus of the HSV-1 gene for DNA polymerase. Thus, the results suggest that the difference in the capacity of two HSV strains to replicate within the trigeminal ganglion of its host and to spread into the brain is determined by nucleotide sequences within the gene for DNA polymerase.

Protection against herpetic ocular disease by immunotherapy with monoclonal antibodies to herpes simplex virus glycoproteins.

In this paper we describe the ability of monoclonal antibodies to prevent herpetic stromal or interstitial keratitis following corneal infection in an outbred mouse model. Monoclonal antibodies recognizing antigenic determinants on glycoproteins B, C, D, and E of herpes simplex virus type 1 were injected intraperitoneally into CF-1 outbred mice 24 or 48 h following inoculation of the cornea with the RE strain of herpes simplex virus type 1. Passive, postexposure immunization with monoclonal antibodies had little effect on the severity of the initial corneal infection or the frequency of latent viral infections in the trigeminal ganglia, except for virus-neutralizing antibodies specific for glycoproteins B and D. A significant correlation was found between the severity of epithelial keratitis and the frequency of latent ganglionic infections. However, immunization with monoclonal antibodies protected the mice against encephalitis and prevented the development of necrotizing stromal keratitis that leads to permanent corneal scarring and blindness. This form of herpetic ocular disease does not respond to antiviral chemotherapy. Since nonneutralizing monoclonal antibodies were just as effective in prevention of encephalitis and stromal keratitis as ones that neutralized the virus in vitro, and antibodies were not administered until 24 or 48 h after corneal inoculation, we suggest that inactivation of infectious virus is not the only protective mechanism in this model.

RNA from an immediate early region of the type 1 herpes simplex virus genome is present in the trigeminal ganglia of latently infected mice.

Transcription of the type 1 herpes simplex virus (HSV-1) genome in trigeminal ganglia of latently infected mice was studied using in situ hybridization. Probes representative of each temporal gene class were used to determine the regions of the genome that encode the transcripts present in latently infected cells. Probes encoding HSV-1 sequences of the five immediate early genes and representative early (thymidine kinase), early-late (major capsid protein), and late (glycoprotein C) genes were used in these experiments. Of the probes tested, only those encoding the immediate early gene product infected-cell polypeptide (ICP) 0 hybridized to RNA in latently infected tissues. Probes containing the other immediate early genes (ICP4, ICP22, ICP27, and ICP47) and the representative early, early-late, and late genes did not hybridize. Two probes covering approximately equal to 30% of the HSV-1 genome and encoding over 20 early and late transcripts also did not hybridize to RNA in latently infected tissues. These results, with probes spanning greater than 60% of the HSV-1 genome, suggest that transcription of the HSV-1 genome is restricted to one region in latently infected mouse trigeminal ganglia.

Immunogenicity of purified glycoprotein gB of herpes simplex virus.

The efficacy of a herpes simplex virus (HSV) component vaccine consisting of viral glycoprotein gB was examined in a mouse system. Immunization of mice with HSV type 1 (HSV-1) gB emulsified in Freund's complete adjuvant or with HSV-1 gB adsorbed to aluminum gel was fully protective against subsequent challenge with HSV-1 or HSV type 2. Latent infection in the trigeminal ganglion was also prevented by immunization with gB.

Experimental development of herpes simplex virus infection in hamster buccal pouch.

In the present study, we have developed an intraoral herpes simplex virus type 1 (HSV-1) infection model in the hamster buccal pouch. This animal model could be used for further oral cancer research related to herpes simplex virus infection.

Monoclonal antibodies suppress replication of herpes simplex virus type 1 in trigeminal ganglia.

The effect of monoclonal antibodies on the growth of herpes simplex virus type 1 in trigeminal ganglia was investigated. Four-week-old mice were infected on an abrased cornea with herpes simplex virus type 1. Forty-eight hours after infection, trigeminal ganglia ipsilateral with infected eyes were removed and placed in culture. Incubation of infected ganglia in the presence of a pool of nonneutralizing monoclonal antibodies specific for glycoproteins of gB and gE suppressed virus growth by greater than 90%. This was comparable to the amount of suppression observed when infected ganglia were incubated in hyperimmune serum. Individual monoclonal antibodies were less efficient, being able to inhibit virus growth by only two- to threefold. The mechanism of suppression was examined. Reduction in virus growth was observed under conditions in which all susceptible ganglion cells were infected in vitro before nonneutralizing monoclonal antibody was added. Similar results were obtained in tests with virus-infected neuroblastoma cells. Furthermore, suppression of infectious progeny was seen in the absence of complement and immunologically reactive cells. Thus, neither virus neutralization nor immunocytolysis could account for the effects of antibody on virus growth. Rather, the data suggest that antibody can bind to herpes simplex virus type 1-infected neuronal cells and suppress intracellular virus replication.

In vitro effect of (E)-5-(2-bromovinyl)-2'-deoxyuridine, 5'-amino-5-iodo-2',5'-dideoxyuridine and 2-deoxy-D-glucose on latent ganglionic herpes simplex virus infection.

(E)-5-(2-Bromovinyl)-2'-deoxyuridine (BVDU) and 5'-amino-5-iodo-2',5'-dideoxy-uridine AIdUrd, blocked the reactivation of latent ganglionic herpes simplex virus in vitro. Furthermore, BVDU, but not AIdUrd, blocked the multiplication of reactivated latent virus and transiently suppressed emergence of reactivated virus from the sensory ganglia after removal of drug from the medium. 2-Deoxy-D-glucose (2-DG) neither prevented the in vitro reactivation of latent virus nor blocked the further multiplication of reactivated latent virus.

Effect of snuff and herpes simplex virus-1 on rat oral mucosa: possible associations with the development of squamous cell carcinoma.

The purpose of this investigation was to study the effect of snuff and experimentally induced herpes simplex virus type 1 (HSV-1) infection in Sprague-Dawley rats. It was demonstrated that it was possible to obtain 100% development of acute HSV-1 infection in the rat oral mucosa, but only 10% of latent reactive infection of the trigeminal ganglia. The rats were, therefore, acutely infected monthly with virus to simulate recurrence of latent infection. Virus was applied topically to the mucous membrane twice with an interval of one month. Snuff was administered between the virus applications and afterwards to half the virus-exposed animals. Sham-infected rats were given snuff during the same period (18 months). A fourth group of rats were left untreated. A complete post-mortem examination was performed. Two rats exposed to snuff and HSV-1 in combination developed squamous cell carcinoma of the oral cavity. It was also found that rats exposed to snuff alone or in combination with HSV-1 had a higher incidence of tumours or tumour-like conditions than control rats exposed to HSV-1 only. The incidence of malignant tumours was significantly higher in rats exposed to snuff or HSV-1 and snuff in combination than in control animals (p less than 0.05). The results of the study indicate that HSV-1 in combination with snuff exposure may be associated with the development of squamous cell carcinomas of the oral cavity.

Development of oral HSV-1 infection model in mice. Evaluation of efficacy of 5'-amino-5-iodo-2',5'-dideoxyuridine.

We developed a new model of oral HSV-1 infection in mice. After oral inoculation, 100 percent of mice developed the clinical lesions at the inoculated area and latent HVS infection in their trigeminal ganglia without mortality. The antiherpetic efficacy of AIdUrd, an agent specifically activated by herpesvirus-encoded enzyme, has been evaluated in this animal model. Early topical or systemic treatment of AIdUrd notably reduced the development of clinical lesions and the virus content in the inoculated lips. However, the establishment of latent HSV infection in the sensory ganglia was not influenced by AIdUrd treatment.

Detection of an immediate early herpes simplex virus type 1 polypeptide in trigeminal ganglia from latently infected animals.

In this study, trigeminal sensory ganglia from animals with acute herpes simplex virus, type 1 (HSV-1) infection were compared to those with a latent infection for the expression of HSV-specific antigens. By the indirect immunofluorescence assay, antisera to an immediate early polypeptide of molecular weight 175,000, designated VP175 or ICP4, and a hyperimmune antiserum to HSV-1 were used to determine whether early viral polypeptides were being expressed in neurons during the latent stage of infection. All 17 ganglia from animals with acute infection (sacrificed 3 to 12 days postinfection) exhibited positive staining when treated either with anti-HSV-1 or with anti-VP175. Forty of 42 ganglia from animals sacrificed during the latent stage of infection (22 to 200 days postinfection) exhibited immunofluorescent staining when treated with anti-VP175. The staining appeared to be similar to that observed in ganglia from acutely infected animals stained with anti-VP175, except that the number and distribution of stained cells were markedly reduced. No immunofluorescence was observed in ganglia from noninfected control animals when stained with anti-VP175 or anti-HSV-1, or when ganglia from latently infected animals were stained with anti-HSV-1 or preimmune serum.

The polypeptide and the DNA restriction enzyme profiles of spontaneous isolates of herpes simplex virus type 1 from explants of human trigeminal, superior cervical and vagus ganglia.

Analysis of the infected cell polypeptides and the DNA restriction profiles of 31 HSV-1 isolates from the trigeminal, superior cervical and vagus ganglia from 17 individuals (12 U.S.A., 2 Japanese, 3 Norwegian) could be classified as 15 different virus strains. With the exception of the three Norwegian isolates which gave identical profiles, virus isolates from the ganglia of different individuals could all be distinguished from one another. In contrast virus isolates from the trigeminal, superior cervical and vagus ganglia of the same individual, or virus isolates from the left and right ganglia of the same individual or multiple isolates from different explants of a single ganglion were indistinguishable. In conclusion, a single virus strain infects each individual initially and virus descended from this event subsequently infects and becomes latent in different cells of the same ganglion as well as in different ganglia.

Attempts to isolate virus from human trigeminal and facial ganglions.

Herpes virus hominis type 1 was isolated from the trigeminal ganglion (ganglion semilunare, gasservian) in three out of 20 randomly selected autopsies. Two of the three patients had been treated with immunosuppressive or cytostatic agents. Clinical signs of herpes infection were not observed during the previous 6 months. No virus was isolated from the facial ganglion (geniculate ganglion) in the same 20 cases. The findings are discussed in relation to the viral etiology of acute peripheral facial palsy.

Oncornavirus particles in neurons of guinea pig trigeminal ganglion.

Virus-like particles morphologically similar to oncornaviruses were observed in trigeminal ganglion neurons of two normal, random-bred, adult Hartley guinea pigs. Only a few neurons showed virus particles, but the particles were numerous in the cells in which they were present. Extracellular virus particles were not observed. Similar oncornavirus particles were observed in trigeminal ganglion explant cultures derived from normal guinea pigs after treatment with bromodeoxyuridine. Both intracellular and extracellular particles were frequently observed in and around supporting cells. Intracytoplasmic oncornavirus-like particles were occasionally observed within neurons. These results support consideration that trigeminal ganglion and other sensory ganglion neurons may be primary sites for latent oncornavirus infection of the nervous system.

Isolation of Herpes simplex virus from human trigeminal ganglia, including ganglia from one patient with multiple sclerosis.

Herpes-simplex virus (H.S.V.) was isolated from 18 of 39 trigeminal ganglia (T.G.) obtained within 12 h of death. The virus was isolated from ten persons who had died of trauma, from one case of lymphoma, and from one case of multiple sclerosis. In the cadaver with histologically confirmed multiple sclerosis, large bilateral areas of demyelination were present near the points of entry of the nerve root, and the possibility that H.S.V. migration to the root entry zone caused demyelination cannot be excluded.

Herpes simplex virus in idiopathic facial paralysis (Bell palsy).

Sera from all 41 adult patients with idiopathic facil paralysis (Bell palsy) and 35 (85%) of 41 matched controls who had never had Bell palsy contained antibodies to herpes simplex virus (P smaller than.05). The frequency of antibodies to herpes zoster virus did not differ in patients and controls. A rise in antibody titer, indicating primary herpes simplex virus infection, was not found in these patients. That Bell palsy may be caused by reactivation of herpes simplex virus is suggested by (1) clinical, neurologic, laboratory, and immunologic similarities between idiopathic facial paralysis and known manifestations of reactivated herpes simplex virus infection, and (2) the known neurotropism of herpes simplex virus, including its presence in latent form in the trigeminal ganglia, and parallels with known facial paralysis due to varicella zoster virus, a closely related agent. The presence of antibodies to herpes simplex virus is the only common factor among the patients tested in this study.