Subacute sclerosing panencephalitis--the continuing threat

Clinical, epidemiological and laboratory findings of four patients with subacute sclerosing panencephalitis (SSPE), diagnosed in Croatia in 2002, were examined. Patient age at disease onset ranged from 5-11 years. All patients were vaccinated regularly with MMR-vaccine. Two patients had a history of measles infection at the age of six and seven months, respectively. In the other two patients, the disease started immediately after the varicella infection. Complement fixing antibody titre to the measles virus (MV) ranged from 1:1024 to 1:65536 in serum, and from 1:16 to 1:128 in cerebrospinal fluid (CSF). In CSF, no antibodies to varicella-zoster virus were found. Brain tissue samples were obtained at autopsy from two patients. In one patient, electron microscopy demonstrated intranuclear viral inclusions (MV nucleocapsids). MV antigen was detected in brain imprints using IFA in both of them. Viral RNA was found in brain tissue samples only, while plasma, serum and CSF were negative. Nucleotide sequence analysis showed that the viruses detected in brain tissue belong to the wild-type MV D6 genotype.     

Human recombinant domain antibodies against multiple sclerosis antigenic peptide CSF114(Glc)

Multiple sclerosis (MS) is a chronic auto‐immune disease characterized by a damage to the myelin component of the central nervous system. Self‐antigens created by aberrant glycosylation have been described to be a key component in the formation of auto‐antibodies. CSF114(Glc) is a synthetic glucopeptide detecting in vitro MS‐specific auto‐antibodies, and it is actively used in diagnostics and research to monitor and quantify MS‐associated Ig levels. We reasoned that antibodies raised against this probe could have been relevant for MS. We therefore screened a human Domain Antibody library against CSF114(Glc) using magnetic separation as a panning method. We obtained and described several clones, and the one with the highest signals was produced as a 6×His‐tagged protein to properly study the binding properties as a soluble antibody. By surface plasmon resonance measurements, we evidenced that our clone recognized CSF114(Glc) with high affinity and specific for the glucosylated peptide. Kinetic parameters of peptide–clone interaction were calculated obtaining a value of K_D in the nanomolar range. Harboring a human framework, this antibody should be very well tolerated by human immune system and may represent a valuable tool for MS diagnosis and therapy, paving the way to new research strategies. Copyright © 2014 John Wiley & Sons, Ltd.     

Protective efficacy of nonneutralizing monoclonal antibodies in acute infection with murine leukemia virus.

We have used an experimental retrovirus infection to study the roles played by different antibodies in resistance to both infection and disease. A molecularly cloned chimeric murine leukemia virus was used to induce acute lethal neurological disease in neonatal mice. A panel of monoclonal antibodies directed against the Gag and Env proteins was tested for protective efficacy. In vitro neutralization assays demonstrated that anti-Env antibodies gave different degrees of neutralization, while no anti-Gag neutralized the virus. In vivo experimental endpoints were onset of clinical signs and premoribund condition. As expected, different anti-Env antibodies demonstrated different degrees of protection which correlated with their neutralizing abilities. Surprisingly, anti-Gag antibodies directed against both p15 (MA protein) and p30 (CA protein) were also protective, significantly delaying the onset of disease. No protection was seen with either of two control antibodies. The protection with anti-Gag was dose related and time dependent and was also produced with Fab fragments. Treatment with anti-Gag did not prevent viremia but resulted in a slight slowing in viremia kinetics and decreased levels of virus in the central nervous systems of mice protected from disease. These data indicate that nonneutralizing antiretroviral antibodies can influence the outcome of retroviral disease. The data also suggest a functional role for cell surface expression of Gag proteins on murine leukemia virus-infected cells.     

Specific antibodies reacting to JC polyomavirus capsid protein mimotopes in sera from multiple sclerosis and other neurological diseases-affected patients

Published data support the hypothesis that viruses could be trigger agents of multiple sclerosis onset. This link is based on evidence of early exposure to viral agents in patients affected by this neurologic disease. JC (JC polyomavirus [JCPyV]), BK (BKPyV), and simian virus 40 (SV40) neurotropic polyomavirus footprints have been detected in brain tissue specimens and samples from patients affected by different neurological diseases. In this investigation, serum samples from patients affected by multiple sclerosis and other inflammatory and noninflammatory neurologic diseases, as well as healthy subjects representing the control, were investigated for immunoglobulin G (IgG) antibodies against JCPyV. To this end, an immunologic approach was employed, which consists of employing indirect enzyme-linked immunosorbent assay testing with synthetic peptides mimicking viral capsid protein 1 antigens. A significantly lower prevalence of IgG antibodies against JCPyV VP1 epitopes, with a low titer, was detected in serum samples from patients with multiple sclerosis (MS) and other neurologic diseases than in healthy subjects. Our study indicates that the prevalence of JCPyV antibodies from patients with multiple sclerosis is 50% lower than in healthy subjects, suggesting specific immune impairments. These results indicate that patients affected by neurological diseases, including MS, respond poorly to JCPyV VP1 antigens, suggesting specific immunologic dysfunctions.     

Vaccines prepared from chimeras of foot-and-mouth disease virus (FMDV) induce neutralizing antibodies and protective immunity to multiple serotypes of FMDV.

The G-H loop of VP1 (residues 132 to 159) of foot-and-mouth disease virus (FMDV) is a prominent feature on the virion surface and has an important role in vaccine efficacy, generation of antigenic variants, and cell binding. Using an infectious cDNA of FMDV, we have constructed serotype A viruses in which the G-H loop has been substituted with the homologous sequences from serotype O or C. These chimeric viruses replicated to high titer and displayed plaque morphologies similar to those of wild-type viruses, demonstrating that the functions provided by the loop can be readily exchanged between serotypes. Monoclonal antibody analyses showed that epitopes contained within the loop were transferred to the chimeras and that epitopes encoded by the type A backbone were maintained. Chemically inactivated vaccines prepared from chimeric viruses induced antibodies in guinea pigs that neutralized both type A and either type O or type C viruses. Swine inoculated with the A/C chimera vaccine also produced cross-reactive antibodies, were protected from challenge with the type A virus, and partially protected against challenge with type C. These studies emphasize the importance of epitopes outside of the G-H loop in protective immunity in swine, which is a natural host of FMDV.     

Persistent rotavirus infection in mice with severe combined immunodeficiency.

Rotaviruses are important pathogens of human infants and the infants of many animal species. The disease produced by these viruses can be described as an acute, self-limiting diarrheal disease, with virus replication localized to the differentiated epithelial enterocytes of the small intestine. Immunologically normal infants shed virus for approximately 5 to 12 days after the onset of infection. Recently, it has been shown that rotavirus can produce a chronic infection in severely immunocompromised children, with virus shedding and intermittent diarrhea lasting from 6 weeks to 2 years (G. A. Losonsky, J. P. Johnson, J. A. Winkelstein, and R. H. Yolken, J. Clin. Invest. 76:2362-2367, 1985; F. T. Saulsbury, J. A. Winkelstein, and R. H. Yolken, J. Pediatr. 97:61-65, 1980). These findings point to an important role for the immune system in recovery from the disease. The study described here examined the outcome of murine rotavirus infection in mice with severe combined B- and T-cell immunodeficiency (SCID) and in immunologically normal seronegative BALB/c mice. Persistent rotavirus infection was established in all mice with SCID which had been inoculated orally as pups. Low levels of virus replication and constant fecal virus shedding characterized the chronic infection. This is the first report of a persistent rotavirus infection in an animal model.     

Reactivation of human herpesvirus-6 in natalizumab treated multiple sclerosis patients

The alpha(4) integrin antagonist natalizumab was shown to be effective in patients with immune-mediated disorders but was unexpectedly associated with JC polyomavirus associated progressive multifocal leukoencephalopathy (PML) in two multiple sclerosis (MS) and one Crohn's disease patients. Impaired immune surveillance due to natalizumab treatment may have contributed to the JCV reactivation. As HHV-6 has been suggested to play a role in MS, we asked whether this virus could also have been reactivated during natalizumab therapy. Matched sera and CSF from a limited set of MS patients treated with and without natalizumab were examined for evidence of HHV-6. In addition, we also superinfected a persistent JC virus infected glial cell with HHV-6A to determine if JC virus can be increased. Elevated serum HHV6 IgG and HHV-6A DNA was detected in the CSF of a subset of patients but not controls. We confirmed that superinfection with HHV-6 of a JC virus infected glial cells increased expression of JCV. These results support the hypothesis that treatment with natalizumab may be associated with reduced immune surveillance resulting in reactivation of viruses associated with MS pathogenesis.     

Assay of interferon and viral antibodies in the cerebrospinal fluid in clinical neurology and psychiatry

Cerebrospinal fluids (CSF) of 245 neurological and 194 psychiatric patients were tested for viral antibodies and interferon. Complement dependent neutralizing antibodies to Herpesvirus hominis 1 were found in the CSF of patients with encephalitis (50.6%), meningitis (35.4%), lesions of peripheral nerves (36.9%), sclerosis multiplex (41.2%), schizophrenia (31.9%), senile dementia (51.4%), mental retardation (11.1%), ethylism (43.5%). Neutralizing antibodies to tick-borne encephalitis virus were found in the CSF of 38% patients with encephalitis, in 14% meningitis, 11% lesions of peripheral nerves and also in 5.6--11.8% of psychiatric patients. In encephalitis, meningitis and in lesions of peripheral nerves were found in the CSF frequently plaque neutralizing antobidies to the tick-borne orbivirus Lipovník, complement-fixing antibodies to lymphocytic choriomeningitis virus and hemagglutination inhibiting antibodies to measles virus. In multiple sclerosis were detected CSF antibodies to measles virus (44%), Herpesvirus hominis 1 (41.2%) and Lipovník virus (52.6%). In neurological patients were observed CSF antibodies simultaneously to two or three viruses in 16.7 to 40.6%, while in psychiatric patients in zero to 4.6%. CSF interferon was found in psychiatric patients with an equal or even higher incidence (33.7 to 57.1%) than in the neurological patients (29.6--38.6%, in multiple sclerosis only 16.7%). Non-interferon virus inhibitors were excluded. The evaluation of the ratio of serum and CSF titers of viral antibodies and of interferon indicated local synthesis of both in the central nervous system -- with the exception of antibodies to Herpesvirus hominis 1 in CSF of some patients with very high titres in serum and probable lesions of the blood brain barrier.     

Lack of neutralizing antibodies to caprine arthritis-encephalitis lentivirus in persistently infected goats can be overcome by immunization with inactivated Mycobacterium tuberculosis

The pathogenesis of the persistent progressive diseases of sheep (visna-maedi) and goats (arthritis-encephalitis) is dependent on continuous replication of the causative lentiviruses. One subgroup of these viruses, Icelandic visna virus, accomplishes this form of replication by undergoing antigenic mutation. Mutant viruses arising late in the infection escape neutralization by antibodies directed to the parental virus. In contrast, we show here that viruses obtained from persistently infected sheep and goats with natural disease in this country do not induce virus-neutralizing antibodies, although antibodies to virus core proteins were produced. The lack of neutralizing antibodies was not overcome by hyperimmunization of animals with concentrated preparations of live or inactivated virus. Thus, failure to produce these specific antibodies was not due to lack of sufficient antigen or interference with the immune response because of the ability of these viruses to infect macrophages. The hyporesponsive state, however, was overcome by immunization of animals with virus and large amounts of inactivated Mycobacterium tuberculosis. Induction of agglutinating and neutralizing antibodies by this method was probably due to a unique form of antigen processing by macrophages activated by M. tuberculosis. Neutralizing antibodies were produced for the first time against the caprine arthritis-encephalitis virus by this method. These antibodies have similar biological properties to those induced by Icelandic visna virus. They belong to the immunoglobulin G1 subclass, they are effective against a narrow range of caprine arthritis-encephalitis viruses, and they identify (for the first time) antigenic variants among these caprine agents.     

Pathogens of house mice on arid Boullanger Island and subantarctic Macquarie Island, Australia

Studies on island populations of house mice (Mus domesticus) and their viruses reveal insights into viral persistence in isolated communities. We surveyed the ectoparasites, endoparasites, and antiviral antibodies for 11 murine viruses and two bacteria of house mice inhabiting two islands off Australia. House mice on Boullanger Island were seropositive to two viruses, murine cytomegalovirus and epizootic diarrhea of infant mice. On subantarctic Macquarie Island, house mice were seropositive for five viruses: murine cytomegalovirus, lymphocytic choriomeningitis virus, mouse parvovirus, epizootic diarrhea of infant mice, and Theiler's murine encephalomyelitis virus. The diversity of antiviral antibodies was lower among populations of house mice on islands than those inhabiting mainland Australia. The decreased diversity of viruses in island populations of house mice may be a function of which agent the founder mice transfer to the island and related to the low densities which the host population may periodically reach over time.     

Characterization of antibodies to idiotypic determinants of monoclonal anti-sperm antibodies

Rabbit polyclonal antibodies to the idiotype of murine monoclonal anti-sperm antibodies were developed and characterized. M29.6 and M42.15 are monoclonal antibodies (mAbs) that inhibit fertilization in vivo and in vitro. Sera from rabbits inoculated with purified mAbs (Ab1) were absorbed with normal mouse and isotype-specific immunoglobulin (Ig); the anti-idiotype Ig fraction (Ab2) was isolated by protein A-chromatography or by chromatography on the corresponding idiotype column. Binding specificity of Ab2 was confirmed by measuring the reactivity of Ab2 with homologous and heterologous mAbs. Ab2 competitively inhibited 125I-labeled Ab1 binding to mouse sperm, suggesting that the Ab2 preparation possessed subpopulations directed against idiotopes similar or adjacent to the antigen-binding site of the mAb. Anti-idiotype antibodies reactive with the antigen-combining site of the anti-sperm mAb may contain subpopulations that mimic the mouse sperm epitope recognized by Ab1. Immunization with Ab2 induced anti-(anti-idiotype) antibodies (Ab3), which competitively inhibited binding of 125I-labeled Ab1 to immobilized Ab2. These results are consistent with the hypothesis that immunization of mice with antibodies to the idiotype of sperm-specific mAbs can induce antibodies that share structural similarities with the anti-sperm mAb used for their induction. Immunization with anti-idiotype antibodies that mimic sperm antigen structure represents a possible strategy for induction of immunity to sperm.     

Sequences between the enhancer and promoter in the long terminal repeat affect murine leukemia virus pathogenicity and replication in the thymus

We previously showed that the 93-bp region between the enhancer and promoter (named DEN for downstream of enhancer) of the long terminal repeat (LTR) of the MCF13 murine leukemia virus is an important determinant of the ability of this virus to induce thymic lymphoma. In this study we observed that DEN plays a role in the regulation of virus replication in the thymus during the preleukemic period. A NF-kappaB site in the DEN region partially contributes to the effect of DEN on both lymphomagenicity and virus replication. To further study the effects of DEN and the NF-kappaB site on viral pathogenicity during the preleukemic period, we examined replication of wild-type and mutant viruses with a deletion of the NF-kappaB site or the entire DEN region in the thymus. Thymic lymphocytes which were infected with wild-type and mutant viruses were predominantly the CD3(-) CD4(+) CD8(+) and CD3(+) CD4(+) CD8(+) cells. The increase in infection by wild-type virus and both mutant viruses of these two subpopulations during the preleukemic period ranged from 9- to 84-fold, depending upon the time point and virus. The major difference between the wild-type and both mutant viruses was the lower rate and lower level of mutant virus replication in these thymic subpopulations. Significant differences in replication between wild-type and both mutant viruses were seen in the CD3(-) CD4(+) CD8(+) and CD3(-) CD4(-) CD8(-) subpopulations, suggesting that these thymic cell types are important targets for viral transformation.     

Phenotypic and functional characterization of T cell clones derived from the cerebrospinal fluid of multiple sclerosis patients

We describe here T cell cultures and clones established from the cerebrospinal fluid (CSF) of three patients with multiple sclerosis (MS) and one chronic meningitis patient with pleocytosis. Most of the cultures were activated with phytohemagglutinin (PHA) before growth in mitogen-free interleukin 2 (IL 2), and were never restimulated. Some of the clones obtained have been propagated for over 1 yr and are strictly IL 2-dependent. Immunofluorescence analysis performed with various monoclonal antibodies revealed that the CSF-derived lines had the characteristics of activated T cells with a stable expression of either suppressor/cytotoxic or helper/inducer surface antigens. Most of the clones established had a predominantly suppressor phenotype (OKT8+), except for the clones derived from one MS patient, which expressed only the helper phenotype (anti-Leu-3a+). Consistent with these data, the CSF-derived cultures displayed a variety of immunoregulatory functions, such as the ability to lyse nonspecific and PHA-stimulated target cells, to produce IL 2 upon mitogenic activation, and to modulate polyclonally induced Ig responses. The availability of long-term CSF T cell cultures derived from MS patients at various disease stages might provide a useful tool in investigating the factor(s) involved in the etio-pathogenesis of the disease.     

Monoclonal antibodies specific for wild mouse neurotropic retrovirus: detection of comparable levels of virus replication in mouse strains susceptible and resistant to paralytic disease.

We used AKR/J mice to produce monoclonal antibodies specific for a neurotropic ecotropic (WM-E) virus initially isolated from wild mice. The rationale for this approach involved the observation that these mice were immunologically hyporesponsive to endogenous ecotropic virus (Akv) but fully responsive to type-specific determinants of WM-E. Hybridoma cell lines derived from mice immunized with both denatured and viable virus produced antibodies with specificity for three viral membrane-associated polypeptides, gp70, p15(E), and p15gag. Epitopes specific for WM-E virus were detected in each of these polypeptides. Cross-reactivity with Friend ecotropic virus (Friend murine leukemia virus) was observed with some gp70- and p15gag-specific antibodies, but no reactivity with endogenous Akv ecotropic virus was seen. The majority of these antibodies did not react with either xenotropic or mink cell focus-forming viruses. Two WM-E-specific anti-gp70 antibodies reacting with different determinants had virus-neutralizing activity in the absence of complement, suggesting that the respective epitopes may participate in receptor binding or virus penetration events. We used these monoclonal antibodies in initial studies to examine the replication of WM-E virus in neonatally inoculated AKR/J mice which are fully resistant to the paralytic disease induced by this virus. Since these mice express high levels of endogenous ecotropic virus, standard assays for ecotropic virus cannot be used to study this question. We present evidence that the resistance to disease does not involve a resistance to virus replication, since these mice expressed levels of viremia and virus replication in spleen and lumbar spinal cord comparable to susceptible NFS/N mice at a time when the latter began to manifest clinical signs of lower-motor-neuron pathology.     

Nucleoprotein-based indirect enzyme-linked immunosorbent assay(indirect ELISA) for detecting antibodies specific to Ebola virus and Marbug virus

Full-length nucleoproteins from Ebola and Marburg viruses were expressed as His-tagged recombinant proteins in Escherichia coli and nucleoprotein-based enzyme-linked immunosorbent assays(ELISAs) were established for the detection of antibodies specific to Ebola and Marburg viruses. The ELISAs were evaluated by testing antisera collected from rabbit immunized with Ebola and Marburg virus nucleoproteins. Although little cross-reactivity of antibodies was observed in antiEbola virus nucleoprotein rabbit antisera, the highest reactions to immunoglobulin G(Ig G) were uniformly detected against the nucleoprotein antigens of homologous viruses. We further evaluated the ELISA's ability to detect antibodies to Ebola and Marburg viruses using human sera samples collected from individuals passing through the Guangdong port of entry. With a threshold set at the mean plus three standard deviations of average optical densities of sera tested, the ELISA systems using these two recombinant nucleoproteins have good sensitivity and specificity. These results demonstrate the usefulness of ELISA for diagnostics as well as ecological and serosurvey studies of Ebola and Marburg virus infection.     

Isolation of Naturally Occurring Viruses of the Murine Leukemia Virus Group in Tissue Culture

A tissue culture cell system for isolation and identification of members of the murine leukemia virus group (the complement fixation for murine leukemia test) was modified to permit the isolation of naturally occurring virus from leukemic and normal mice. The important factors for increasing the sensitivity of the test were the use of National Institutes of Health (NIH) strain Webster Swiss embryo cell cultures and the selection of rat-immune sera having complement-fixing antibodies to tissue culture antigens of both the Gross and FMR subgroups. In all, 163 strains of mouse leukemia virus, from 11 inbred mouse strains, have been isolated. Representative virus isolates were shown to possess the properties of the murine leukemia virus group; i.e., they were chloroform-sensitive, noncytopathic agents which replicated in mouse embryo tissue culture and produced group-reactive, complement-fixing antigen and budding C-type particles visible by electron microscopy. These viruses could serve as helpers in the rescue of Moloney sarcoma virus genome from non-producer hamster sarcoma cells, yielding pseudotypes. All of the 19 field isolates tested were neutralized by Gross passage A antiserum but not by potent antisera to the Moloney, Rauscher, and Friend strains. Virus was recovered regularly from embryos and from the plasma and spleen of adult mice of high leukemic strains. In low leukemic mouse strains, different patterns of virus detection were observed. In C3H/He mice, virus was occasionally present in embryos and was found in 40% of adult spleens. BALB/c mice were virus-negative as fetuses or weanlings, but spleens of more than half of the mice over 6 months of age yielded virus. NIH mice have never yielded virus. In reciprocal matings between AKR and BALB/c mice, virus recovery from embryos was maternally determined. The development of tissue culture isolation procedures made possible for the first time the application of classical infectious disease methods to the study of the natural history of murine leukemia virus infection.     

Genetic and Infectious Profiles Influence Cerebrospinal Fluid IgG Abnormality in Japanese Multiple Sclerosis Patients

Background

Abnormal intrathecal synthesis of IgG, reflected by cerebrospinal fluid (CSF) oligoclonal IgG bands (OBs) and increased IgG index, is much less frequently observed in Japanese multiple sclerosis (MS) cohorts compared with Western cohorts. We aimed to clarify whether genetic and common infectious backgrounds influence CSF IgG abnormality in Japanese MS patients.

Methodology

We analyzed HLA-DRB1 alleles, and IgG antibodies against Chlamydia pneumoniae, Helicobacter pylori, Epstein-Barr virus nuclear antigen (EBNA), and varicella zoster virus (VZV) in 94 patients with MS and 367 unrelated healthy controls (HCs). We defined CSF IgG abnormality as the presence of CSF OBs and/or increased IgG index (>0.658).

Principal Findings

CSF IgG abnormality was found in 59 of 94 (62.8%) MS patients. CSF IgG abnormality-positive patients had a significantly higher frequency of brain MRI lesions meeting the Barkhof criteria compared with abnormality-negative patients. Compared with HCs, CSF IgG abnormality-positive MS patients showed a significantly higher frequency of DRB1*1501, whereas CSF IgG abnormality-negative patients had a significantly higher frequency of DRB1*0405. CSF IgG abnormality-positive MS patients had a significantly higher frequency of anti-C. pneumoniae IgG antibodies compared with CSF IgG abnormality-negative MS patients, although there was no difference in the frequency of anti-C. pneumoniae IgG antibodies between HCs and total MS patients. Compared with HCs, anti-H. pylori IgG antibodies were detected significantly less frequently in the total MS patients, especially in CSF IgG abnormality-negative MS patients. The frequencies of antibodies against EBNA and VZV did not differ significantly among the groups.

Conclusions

CSF IgG abnormality is associated with Western MS-like brain MRI features. DRB1*1501 and C. pneumoniae infection confer CSF IgG abnormality, while DRB1*0405 and H. pylori infection are positively and negatively associated with CSF IgG abnormality-negative MS, respectively, suggesting that genetic and environmental factors differentially contribute to MS susceptibility according to the CSF IgG abnormality status.     

Characterization of individual mouse cerebrospinal fluid proteomes

Analysis of cerebrospinal fluid (CSF) offers key insight into the status of the CNS. Characterization of murine CSF proteomes can provide a valuable resource for studying CNS injury and disease in animal models. However, the small volume of CSF in mice has thus far limited individual mouse proteome characterization. Through nonterminal CSF extractions in C57Bl/6 mice and high‐resolution 2D‐LC MS/MS analysis of individual murine samples, we report the most comprehensive proteome characterization of individual murine CSF to date. We identified a total of 566 unique proteins, including 128 proteins from three individual CSF samples that have been previously identified in brain tissue. Our methods and analysis provide a mechanism for individual murine CSF proteome analysis. The data are available in the ProteomeXchange with identifier PXD000248 ( http://proteomecentral.proteomexchange.org/dataset/PXD000248 ).     

Significant Low Prevalence of Antibodies Reacting with Simian Virus 40 Mimotopes in Serum Samples from Patients Affected by Inflammatory Neurologic Diseases,Including Multiple Sclerosis

Many investigations were carried out on the association between viruses and multiple sclerosis (MS). Indeed, early studies reported the detections of neurotropic virus footprints in the CNS of patients with MS. In this study, sera from patients affected by MS, other inflammatory (OIND) and non-inflammatory neurologic diseases (NIND) were analyzed for antibodies against the polyomavirus, Simian Virus 40 (SV40). An indirect enzyme-linked immunosorbent assay (ELISA), with two synthetic peptides, which mimic SV40 antigens, was employed to detect specific antibodies in sera from patients affected by MS, OIND, NIND and healthy subjects (HS). Immunologic data indicate that in sera from MS patients antibodies against SV40 mimotopes are detectable with a low prevalence, 6%, whereas in HS of the same mean age, 40 yrs, the prevalence was 22%. The difference is statistically significant (P = 0.001). Significant is also the difference between MS vs. NIND patients (6% vs. 17%; P = 0.0254), whereas no significant difference was detected between MS vs OIND (6% vs 10%; P>0.05). The prevalence of SV40 antibodies in MS patients is 70% lower than that revealed in HS.     

The major virus-producing cell type during murine cytomegalovirus infection, the hepatocyte, is not the source of virus dissemination in the host

The course of systemic viral infections is determined by the virus productivity of infected cell types and the efficiency of virus dissemination throughout the host. Here, we used a cell-type-specific virus labeling system to quantitatively track virus progeny during murine cytomegalovirus infection. We infected mice that expressed Cre recombinase selectively in vascular endothelial cells or hepatocytes with a murine cytomegalovirus for which Cre-mediated recombination would generate a fluorescently labeled virus. We showed that endothelial cells and hepatocytes produced virus after direct infection. However, in the liver, the main contributor to viral load in the mouse, most viruses were produced by directly infected hepatocytes. Remarkably, although virus produced in hepatocytes spread to hepatic endothelial cells (and vice versa), there was no significant spread from the liver to other organs. Thus, the cell type producing the most viruses was not necessarily the one responsible for virus dissemination within the host.