PubMed Health⌕ Search

Biomedical subjects

W Lüke

Publications and source records attributed to W Lüke.

At least 19 recordsLinked to original sources
PubMed2001

Immune response in progressive multifocal leukoencephalopathy: an overview.

Progressive multifocal leukoencephalopathy (PML) is a disease usually occurring in immunosuppressed patients. By far the most common underlying immunosuppressive illness is the acquired immune deficiency syndrome, accounting for about 85% of PML cases currently seen in clinical practice. PML may occur in patients with deficits in the humoral and/or cellular immune response such as lymphoproliferative diseases, myeloproliferative diseases, carcinomatous diseases and acquired immunodeficiency due to autoimmune diseases and immunosuppressive therapy. The humoral immune response in PML is indicative of a persistent, reactivated infection with a prominent immunoglobulin (lgG) G synthesis to virus protein 1 (VP1). An lgM synthesis in serum is rarely found. In about 76% of PML cases, an intrathecal humoral immune response to recombinant VP1 can be found as compared to only 3.2% in healthy controls. The detection of intrathecally synthesized lgG antibodies to VP1 can be used as an additional diagnostic test for the diagnosis of PML. The magnitude of the intrathecal humoral immune response appears to rise over time and may be associated with a decrease of viral load in cerebrospinal fluid (CSF) and possibly the central nervous system (CNS). Compared to healthy controls, proliferation of peripheral blood mononuclear cells (PBMC) is reduced in PML patients. Immunological studies suggest a general impairment of the Th1-type T-helper cell function of cell-mediated immunity. Furthermore, the appearance of JCV-specific cytotoxic T-lymphocytes appears to be associated with a favorable clinical outcome.

Antibody Formation↗
PubMed2001

Cellular and humoral immune response in progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a fatal, demyelinating disease caused by JC virus (JCV) in patients with severe immunosuppression. We studied the JCV-specific cellular and humoral immune response in 7 healthy donors (HD), 6 human immunodeficiency virus-1 (HIV-1)-infected patients without PML (HIV), 4 HIV-1-negative patients with PML (PML), and 8 HIV-1-positive patients with PML (HIV/PML). As antigens, recombinant virus-like particles of the major structural protein VP1 (VP1-VLP) of JCV, tetanus toxoid (TT), or the mitogen phytohemagglutinin (PHA) were used. Proliferation of peripheral blood mononuclear cells (PBMC) after stimulation with the VP1-VLP was significantly suppressed in PML and HIV/PML patients compared to HD. After antigen stimulation the production of interferon-gamma (IFN-gamma) was reduced in PML, in HIV/PML, and in HIV patients. The production of interleukin-10 (IL-10), however, was elevated in HIV/PML patients. Neither proliferation nor cytokine production correlated with the presence of JCV DNA in PBMC. The immunoglobulin G serum antibody titer to the VP1-VLP was slightly elevated in HIV, elevated in PML, and highly elevated in HIV/PML patients compared to HD. The development of PML appears to coincide with a general impairment of the Th1-type T-helper cell function of cell-mediated immunity.

Cytokines↗
PubMed2000

Packaging of small molecules into VP1-virus-like particles of the human polyomavirus JC virus.

Recombinantly expressed VP1-virus-like particles (VP1-VLP) of human polyomavirus JC virus (JCV) were described recently as a new DNA transporter system. It was shown that DNA molecules could be packaged into VP1-VLP during a controlled chemical reassociation/dissociation process. In the present study VP1-VLP were studied as carriers for pharmaceutical substances. Propidium iodide (PI) was packaged into VP1-VLP as a reporter molecule. The PI-containing VP1-VLP could be detected directly by flow cytometry. The fluorescence intensity of the VP1-VLP depended strongly on the initial PI concentration. This packaging method is easy to handle and applicable to viruses and VP1-VLP which can be dissociated and reassociated chemically.

Capsid↗
PubMed2000

Highly active antiretroviral therapy and progressive multifocal leukoencephalopathy: effects on cerebrospinal fluid markers of JC virus replication and immune response.

Cerebrospinal fluid (CSF) samples were examined from 7 patients infected with human immunodeficiency virus type 1 (HIV-1) who had progressive multifocal leukoencephalopathy (PML). Samples were obtained both before and after 35-365 days of highly active antiretroviral therapy (HAART). By polymerase chain reaction, JC virus (JCV) DNA was found in 6 of 7 patients at baseline but in only 1 patient after HAART. In contrast, in 25 historical control patients from whom sequential CSF specimens were obtained, no reversion from detectable to undetectable JCV DNA was observed. By use of enzyme-linked immunosorbent assay, intrathecal production of antibody to JCV-VP1 was shown in only 1 of 4 HAART recipients at baseline but in 5 of 5 patients after treatment. The neuroradiological picture improved or had stabilized in all patients after 12 months of HAART, and all were alive after a median of 646 days (range, 505-775 days). Prolonged survival after HAART for PML is associated with JCV clearance from CSF. JCV-specific humoral intrathecal immunity may play a role in this response.

AIDS-Related Opportunistic Infections↗
PubMed2000

Naturally occurring V1-env region variants mediate simian immunodeficiency virus SIVmac escape from high-titer neutralizing antibodies induced by a protective subunit vaccine.

Macaques which developed high-titer neutralizing antibodies (htNAb) after immunization with a virion-derived oligomeric envelope glycoprotein subunit vaccine were protected against a homologous simian immunodeficiency virus SIVmac challenge. Here we demonstrate that the htNAb could be overcome by V1-env region variants isolated ex vivo from an SIVmac-infected macaque. The results further suggest that the development of V1-env region neutralization escape mutants is also necessary for survival of the virus in infected macaques. The immunological capacity of a single variable region to induce neutralizing antibodies in vaccinated and infected macaques initiate new ideas for a successful vaccine strategy.

Amino Acid Sequence↗
PubMed1999

Molecular cloning and expression of major structural protein VP1 of the human polyomavirus JC virus: formation of virus-like particles useful for immunological and therapeutic studies.

The major structural viral protein, VP1, of the human polyomavirus JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), was expressed by using recombinant baculoviruses. Recombinant VP1 formed virus-like particles (VLP) with the typical morphology of empty JCV capsids. Purified VP1 VLP bind to SVG, B, and T cells, as well as to monkey kidney cells. After binding, VP1 VLP were also internalized with high efficiency and transported to the nucleus. Immunization studies revealed these particles as highly immunogenic when administered with adjuvant, while immunization without adjuvant induced no immune response. VP1 VLP hyperimmune serum inhibits binding to SVG cells and neutralizes natural JCV. Furthermore, the potential of VP1 VLP as an efficient transporter system for gene therapy was demonstrated. Exogenous DNA could be efficiently packaged into VP1 VLP, and the packaged DNA was transferred into COS-7 cells as shown by the expression of a marker gene. Thus, VP1 VLP are useful for PML vaccine development and represent a potential new transporter system for human gene therapy.

Animals↗
PubMed1998

Prechallenge high neutralizing antibodies and long-lasting immune reactivity to gp41 correlate with protection of rhesus monkeys against productive simian immunodeficiency virus infection or disease development.

To investigate the protective efficacy of various gp130 vaccine preparations, rhesus monkeys were immunized with gp130 oligomers (O-gp130) or two different gp130-monomer preparations (M1-gp130; M2-gp130) and challenged with 50 MID50 of simian immunodeficiency virus (SIV)mac32H. Following challenge the control animals and all animals of the M1- and M2-gp130 group and 1 animal of the O-gp130 group were productively infected, whereas 3 animals of the O-gp130 group resisted the productive virus replication. The protection was correlated with high neutralizing antibodies and a long-lasting immune response to the transmembrane protein gp41. Whereas none of the O-gp130 animals had developed disease symptoms, 3 M1-gp130 animals, 1 M2-gp130 animal, and 2 control animals died as a result of AIDS within 18 months after challenge. Therefore, immunization with virion-derived gp130 oligomers of SIVmac32H can confer protection against the productive infection with SIVmac32H and suppress the development of the AIDS-like disease.

Animals↗
PubMed1998

A rapid and sensitive bacterial assay to determine the inhibitory effect of 'interface' peptides on HIV-1 protease co-expressed in Escherichia coli.

The HIV-1 protease is essential for maturation of virus particles and is, therefore, an attractive target for antiviral drugs. The function of this protease depends on the dimerization of two identical subunits. Commonly used protease inhibitors are directed mainly against the active site of the enzyme which often leads to viral resistance. To determine the inhibitory effect of peptides interfering with the dimerization site of the HIV-1 protease, a recombinant bacterial screening assay was established. Escherichia coli was co-transformed with two different plasmids, expressing the 'interface' peptide and an active HIV-1 protease toxic for the bacteria. Co-expression of inhibitory peptides overcomes the incomplete membrane transmission of supplemented inhibitors and leads to a direct interaction of the inhibitory peptide and the HIV-1 protease. The inhibitory effect of co-expressed peptides was measured by an increased growth of co-transformed bacteria, compared with a slowly growing E. coli control culture only expressing the HIV-1 protease. Using this assay several penta- and hexa-peptides were screened for their ability to inhibit HIV-1 protease activity. One of these peptides showed a significant inhibitory effect on co-expressed recombinant HIV-1 protease.

Amino Acid Sequence↗
PubMed1997

Detection of JC virus by anti-VP1 immunohistochemistry in brains with progressive multifocal leukoencephalopathy.

We have assessed the diagnostic efficacy of a novel polyclonal rabbit antiserum directed to the recombinant major capsid protein VP1 of JC virus (JCV). Immunohistochemistry for VP1 was compared to non-radioactive JCV DNA in situ hybridization (ISH) in ten cases of progressive multifocal leukoencephalopathy (PML). Tissue sections from postmortem brains were studied from PML patients suffering from immunodeficient conditions of various causes: immunodeficiency syndrome (AIDS, n = 7), severe combined immune deficiency due to adenosine deaminase deficiency (n = 1), sarcoidosis (n = 1) and leukemia (n = 1). VP1 immunohistochemistry demonstrated the presence of JCV in lesional oligodendrocytes of all PML patients, whereas ISH was able to detect JCV in nine out of ten cases. We conclude that VP1 immunohistochemistry is a specific, sensitive and rapid method for confirming the diagnosis of PML.

Adult↗
PubMed1997

Detection of CSF-specific oligoclonal antibodies to recombinant JC virus VP1 in patients with progressive multifocal leukoencephalopathy.

The intrathecal synthesis of antibodies against recombinant VP1, the major structural protein of JC virus (JCV), was studied in 18 patients with progressive multifocal leukoencephalopathy (PML) and in 31 patients with various neurological disorders. Two methods were used, the calculation of an antibody specific index (ASI) on one hand and an antigen-driven immunoblotting for the detection of oligoclonal antibodies on the other. Most PML patients displayed an elevated (> 1.5) ASI (78%) and anti-VP1 oligoclonal antibodies restricted to the cerebrospinal fluid (55%). Only two other patients (one case each of multiple sclerosis and of neuroborreliosis) also showed an intrathecal synthesis of anti-VP1 oligoclonal antibodies, likely as a result of a 'polyspecific' reaction within the central nervous system.

Antibodies, Viral↗
PubMed1997

Efficient production of JC virus in SVG cells and the use of purified viral antigens for analysis of specific humoral and cellular immune response.

A new in vitro system for the production of the human polyomavirus JC virus (JCV) was established to circumvent the need for virus growth in primary human fetal glial cells (PHFG). The permanent cell line SVG, transformed by an origin-defective mutant of Simian Virus 40 (SV40) was used to grow JCV. JCV-specific RNA could be detected at day 5 and viral antigen at day 6 post infection (p.i.). Virus production peaked at day 16. Virus could be purified by differential centrifugation. The purified fraction consisted mainly of mature particles but contained also pentamers of the major structural virus protein 1 (VP1). The VP1-pentamers could be purified to near homogeneity. The purified virus particles stimulated a specific T-cell proliferation of peripheral blood monocytes (PBMCs) of a patient with progressive multifocal leukoencephalopathy (PML) and of two healthy individuals. In addition, JCV-particles and VP1-pentamers reacted specifically in an ELISA with a series of five PML-patient sera and four sera of individuals not affected by PML. These results demonstrate that purified whole virus particles are suitable for the analysis of specific cellular and humoral immune responses to JCV.

Animals↗
PubMed1997

Polymerase chain reaction for detection of JC virus DNA in cerebrospinal fluid: a quality control study. European Union Concerted Action on Viral Meningitis and Encephalitis.

The sensitivity and specificity of PCR of CSF for the diagnosis of progressive multifocal leuko encephalopathy is estimated at 75 and 98.5%, respectively. However, inter-laboratory and inter-technique variations have been shown to produce wide variations. A 10-fold dilution series of JC virus in cerebrospinal fluid was prepared and circulated for 'blind' evaluation in laboratories participating in a European Union Concerted Action on Virus Meningitis and Encephalitis. Six of seven laboratories returned results with sensitivity of between 10 and 1 JCV DNA copy equivalents per 10 microl of CSF, one laboratory detected 10(5) copies per 10 microl of CSF. These results demonstrate the feasibility of using virus diluted in CSF for comparison of PCR techniques, and that the range of sensitivity of JCV PCR in proficient laboratories is between 10 and 1 copy equivalents per 10 microl of CSF.

Aged↗
PubMed1997

Analysis of the systemic and intrathecal humoral immune response in progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a subacute viral infection of oligodendrocytes by JC virus occurring almost exclusively in immunocompromised patients. By use of partially purified recombinant VP1 as antigen, the IgG response was analyzed by a quantitative ELISA of paired cerebrospinal fluid (CSF) and serum samples. An intrathecal immune response to VP1, defined as an antibody-specificity index of CSF to serum antibody titers > or =1.5, was found in 76% of PML patients (47/62) but in only 3.2% of controls (5/155) (P < .001). Intra-blood-brain barrier synthesis of VP1-specific IgG antibodies is 76% sensitive and 96.8% specific for the diagnosis of PML. Furthermore, the excellent correlation (r = .985) between the plasma cell count in brain tissue and the humoral intrathecal immune response to VP1 in PML patients suggests a role for B cells in this disorder.

Adolescent↗
PubMed1997

Identification of the V1 region as a linear neutralizing epitope of the simian immunodeficiency virus SIVmac envelope glycoprotein.

The sequence variability of viral structure polypeptides has been associated with immune escape mechanisms. The V1 region of simian immunodeficiency virus (SIV) is a highly variable region of the SIVmac env gene. Here, we describe the V1 region as a linear neutralizing epitope. V1 region-specific neutralizing antibodies (NAb) were first demonstrated in a rabbit infected with a recombinant vaccinia virus carrying the env gene of human immunodeficiency virus type 2 strain ben (HIV-2ben). Since we detected in this animal V1 region-specific NAb that were able to neutralize not only human immunodeficiency virus type 2 but also SIVmac32H, we investigated whether a similar immune response is evoked in macaques (Macaca mulatta) either infected with SIVmac or immunized with the external glycoprotein (gp130) of the same virus. Distinctly lower NAb titers were found in the SIVmac-infected animals than in the gp130-immunized macaques. Since the NAb titers in both groups were high enough for competition experiments, we used five overlapping peptides encompassing the whole V1 region for a detailed identification of the epitope. In each of the 12 macaques investigated, we detected a high level of NAb reacting with at least one peptide located in the central part of the V1 region. The relatively high degree of divergence, especially within the central part of the V1 region, which characterized the evolution of the retroviral sequences from the original inoculum in the infected macaques suggests the development of escape mutants. Furthermore, 3 of 12 animals developed NAb directed against the amino-terminal end of the V1 region epitope. Sequence analysis, however, revealed relatively low levels of genetic drift and genetic variability within this part of the V1 region. The induction of V1 env-specific NAb not only in gp130-immunized macaques but also in SIVmac-infected animals in combination with the increased genetic variability of this region in vivo indicates a marked biological significance of this epitope for the virus.

Amino Acid Sequence↗
PubMed1997

Infection of macaque monkeys with simian immunodeficiency virus: an animal model for neuro-AIDS.

Due to the worldwide AIDS pandemic, HIV-1 has become the major factor for central nervous system (CNS) diseases. Two major disorders of the CNS caused by HIV-1 have been described, a meningoencephalitis which occurs in 30-50% of patients early after infection and the AIDS dementia complex (ADC, also known as HIV-associated dementia) which is characterized by a predominantly subcortical dementia. The pathophysiology of these clinical syndromes still remains an enigma. However, since monocytes/macrophages may represent the major place of virus replication in the CNS, a hematogenous invasion of HIV-1 into the brain may be crucial to the neuropathogenesis of ADC. One of the most valuable animal models for the study of neuro-AIDS is the infection of macaque monkeys with the simian immunodeficiency virus (SIV). In about 50% of infected rhesus monkeys with an AIDS-like disease, neuropathological lesions similar to ADC in men have been observed. This animal model contributes to our understanding of the mechanisms of viral neuroinvasion early after infection and in the development of neurological disease. In this review we will summarize the state of the art and will focus on further questions concerning the neuropathogenesis of HIV/SIV.

AIDS Dementia Complex↗
PubMed1996

Cell-mediated immune response of macaques immunized with low doses of simian immunodeficiency virus (SIV).

Many uninfected people at high risk of HIV infection developed an HIV-specific cellular immune response despite their lack of seroconversion. Therefore, they must have been exposed to HIV without subsequent infection. It has been concluded from these data, that cell-mediated immunity (CMI) rather than humoral immunity might confer protection to HIV infection. Therefore, we tried to induce such a strong CMI in macaques by different immunization strategies. Five or seven animals were immunized with high or low doses of a whole SIV split vaccine. The lower dose of the vaccine provoked a stronger T-helper cell (TH) proliferation than the higher dose, which led to a pronounced humoral immune response. To induce a strong CMI without any specific antibody response, five macaques were inoculated with low doses of infectious SIV. None of these animals seroconverted but each animal developed a SIV-specific TH response. Interestingly, we could neither detect an SIV-specific CTL activity in the animals nor did we find typical TH1- or TH2-like cytokine profiles investigating stimulated bulk-cultures from SIV-exposed animals by RT-PCR. 24 weeks after the first low dose SIV exposure the animals were boosted by a second low dose of SIV followed by a subsequent intravenous challenge with a high dose of SIV 12 weeks later. Unexpectedly, none of the animals was found to be protected against infection and the development of AIDS-like symptoms.

Animals↗