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Biomedical subjects

W Bodemer

Publications and source records attributed to W Bodemer.

At least 19 recordsLinked to original sources
PubMed1998

Elevated serum level of soluble CD23 precedes development of B-non-Hodgkin's lymphoma in SIV-infected Rhesus monkeys.

Patients with HIV infection are at high risk for the development of high-grade B-non-Hodgkin's lymphoma (B-NHL). The aim of this study was identification of a predictive diagnostic marker for HIV-associated B-cell lymphomas, using simian-immunodeficiency-virus (SIV)-infected Rhesus monkeys as a well-established in vivo model of HIV-associated lymphomagenesis. We infected 26 monkeys (Macaca mulatta) with SIVmax and measured serum levels of sCD23 longitudinally until necropsy. Of the 26 monkeys, 9 developed high-grade B-NHL, which was preceded by lymphadenopathy (NHL+/LA+) (group 1). Among the 17 animals that remained without clinical evidence of lymphoma during the observation period, 8 developed LA (group 2) and 9 were NHL- and LA-negative (NHL-/LA-) (group 3). Elevation of sCD23 serum levels preceded B-cell lymphoma development, with a median of 44 U/ml in group 1 vs. 7 U/ml and 8 U/ml in groups 2 and 3 respectively, 32 weeks after infection. Differences in the serum level of sCD23 between group 1 vs. groups 2 and 3 became statistically significant 32 to 56 weeks after infection. At necropsy, serum levels of sCD23 were significantly higher in group 1 than in group 2 or group 3; 6/6 samples of SIV-associated B-NHL were positive for gene transcription of CD23 and its receptor CD21 as assessed by RT-PCR. The data point to a potential role of sCD23 as a predictive marker for the development of HIV-associated B-NHL. Moreover, the in vivo model of SIV-infected monkeys suggests the possibility of exactly analyzing the pathobiological role of sCD23 in the lymphomagenesis of SIV-associated B-NHL.

Animals↗
PubMed1997

Cytokine gene transcription in simian immunodeficiency virus and human immunodeficiency virus-associated non-Hodgkin lymphomas.

Infection of rhesus monkeys with SIV leads to AIDS-like symptoms. Similar to human AIDS patients, some monkeys develop B cell non-Hodgkin lymphoma (NHL). We determined transcription of cytokine genes regulating the activation of B and T cells, which play a role in intratumoral immune surveillance. Therefore, we compared the transcription of the cytokine genes encoding IL-2, IL-4, IL-6, IL-10, IFN-gamma, TNF-alpha, and TGF-beta1, and the Epstein-Barr virus-encoded BCRF 1 gene, in cells from five monkey and two human tumor specimens. The immune-suppressive IL-10 and TGF-beta1 genes were predominantly transcribed in all tumor specimens analyzed. Cytokine gene transcription patterns appeared to be similar in human and animal tumor cells. The transcription patterns corresponded to their histological classification as diffuse large-cell lymphoma according to the REAL classification and as immunoblastic or centroblastic tumors according to the Kiel classification. The determination of cytokine gene transcription pattern in the NHL may improve our understanding of pathogenesis and immune surveillance in this heterogeneous group of tumors. Our data show that SIV-associated NHLs of rhesus monkeys are comparable to human HIV-1-associated EBV-positive non-Hodgkin lymphoma.

Animals↗
PubMed1997

Detection of Epstein-Barr virus small RNAs EBER1 and EBER2 in lymphomas of SIV-infected rhesus monkeys by in situ hybridization.

SIV infection of macaques is a well-established animal model for studying the pathogenesis of HIV infection in humans. During the course of SIV infection, up to 40% of cynomolgus macaques (Macaca fascicularis) develop SIV-associated non-Hodgkin's lymphomas. In the present study, we characterized malignant lymphomas of SIV(mac) 251/32H-infected rhesus macaques (Macaca mulatto) of our cohort in terms of clinical outcome, histopathology and EBV association. Histopathologic changes of lymphoid malignancies were classified according to the Kiel classification. For detection of the EBV-encoded small RNAs EBER1 and EBER2, a method of non-isotopic in situ hybridization was established. The presence of EBNA-2 antigens was assessed by immunohistochemistry. Seven of 43 rhesus macaques developed highly malignant B-cell lymphomas of the centroblastic, immunoblastic and Burkitt subtypes within 18-29 months post-experimental SIV infection. In situ hybridization revealed the presence of small EBER1 and -2 RNAs in 6 of 7 disease cases. EBNA-2 antigens could be demonstrated in only 4 of 7 tissue specimens. As expected, the Burkitt-type of lymphoma was negative for EBNA-2 antigen staining. In accordance with findings on SIV-associated lymphomas of cynomolgus macaques, infection with an EBV-related herpesvirus could be demonstrated in almost 90% of lymphomas in SIV-infected rhesus macaques. In contrast, the presence of EBV in lymphomas had been documented previously in only 30-40% of HIV-infected patients. Further studies should thus define the precise role of herpesvirus infection for lymphomagenesis in SIV- and HIV-induced immunodeficiency.

Animals↗
PubMed1997

Generation of herpes virus saimiri-transformed T-cell lines from macaques is restricted by reactivation of simian spuma viruses.

Herpes virus saimiri (HVS) transforms human T-cells in vitro to stable growth. These T-cell lines retain their immunological characteristics of the parent cells and do not release infectious virus. Recently, lymphocytes of Old World monkeys were efficiently transformed by HVS. In parallel to these studies we initiated transformation experiments by infecting peripheral blood cell cultures of 45 monkeys, 35 rhesus and 10 cynomolgus macaques. In only three cases, we obtained transformed T-cell lines. The transformed T-cells were largely double-positive for CD4 and CD8. They responded with increased proliferation to mitogenic or IL-2 stimulation and transcribed mRNA for IL-2, IL-4, and IL-10. However, most initiated T-cell cultures from macaques developed giant cells. The cytopathic agent was identified as simian foamy virus (SFV) as confirmed by PCR, immunofluorescence, and coculture experiments. Treatment of the T-cell cultures with AZT- and SFV-specific sera did only shortly prolong the life-span of the cultures. Therefore, the reactivation of SFV caused remarkable difficulties in the establishment of macaque T-cell lines by HVS. This seems to be a general problem since most animals from several breeding colonies are SFV-positive.

Animals↗
PubMed1997

Impaired mitogen-driven proliferation and cytokine transcription of lymphocytes from macaques early after simian immunodeficiency virus (SIV) infection.

Altered cytokine transcription might play an important role in the pathogenesis of human immunodeficiency virus (HIV) infection in humans. The infection of rhesus macaques with simian immunodeficiency virus (SIV) provides a relevant animal model for HIV infection. Therefore, we evaluated the cyokine transcription of phytohemagglutinin (PHA)-stimulated lymphocytes in the early phase after infection of four rhesus macaques with pathogenic SIV-mac239. To determine transcription of interleukin (IL)-2, interferon (IFN)-gamma, IL-4, IL-6, and IL-10 we established a semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). After inoculation with SIV, all monkeys became productively infected and developed an acquired immunodeficiency syndrome (AIDS) like disease. Infection was associated with a proliferation dysfunction of monkey lymphocytes in response to PHA. In addition, a decreasing overall cytokine transcription could be observed during the course of SIV infection. These findings demonstrate that an impairment of the lymphocyte function is associated with a reduced cytokine transcription in the early phase of an immunodeficiency virus infection. The observed differences of cytokine expression might contribute to the impaired immune response of SIV-infected monkeys and HIV-infected humans.

Animals↗
PubMed1996

Induction of antibodies against human prion proteins (PrP) by DNA-mediated immunization of PrP0/0 mice.

Prion diseases are neurodegenerative disorders, affecting humans and animals. The human diseases include kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), and fatal familial insomnia (FFI). To generate monospecific antisera against human prion proteins we have immunized mice with DNA coding for different human prion proteins. We constructed immunization vectors expressing individual genotypes of either the cellular prion gene (PRNP) or mutant forms under appropriate promoters. This approach avoids the preparation of infectious material for immunization. To circumvent immunological tolerance prion protein-deficient PrP0/0 mice were used for the DNA-mediated immunization. Thereby monospecific sera were raised capable of specifically precipitating in vitro synthesized human prion proteins. With prion protein-specific peptide ELISAs, we found that antibodies are predominantly directed against the octapeptide repeat region and to a lesser extent to regions comprising the signal peptide, the neurotoxic domain or the GPI anchor. In contrast, prion gene-positive (PrP+/+) BALB/c mice immunized under the same experimental conditions as the PrP0/0 mice did not respond with antibody formation against the human prion protein. This is the first report clearly showing that immune competent prion protein-deficient mice react with a vigorous polyclonal immune response after DNA-mediated immunization with human prion gene sequences.

Amino Acid Sequence↗
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↗
PubMed1996

T cell apoptosis in human immunodeficiency virus type 2- and simian immunodeficiency virus-infected macaques.

Recent evidence suggests that T cell apoptosis could be involved in the pathogenesis of HIV infection. In addition, lymphocyte apoptosis has been described in SIV-infected macaques that developed simian AIDS. To investigate further the role of apoptosis in AIDS pathogenesis, we studied lymphocytes of HIV-2-infected cynomolgus macaques that did not develop simian AIDS. We compared apoptosis of lymphocytes from animals infected with non-pathogenic HIV-2 to that in macaques infected with pathogenic SIV. Unfractionated peripheral blood mononuclear cells of SIV- and HIV-2-infected macaques showed evidence of apoptosis by electron microscopy, flow cytometry (terminal dUTP nick end labelling) and visualization of DNA fragmentation. Between 30-50% apoptotic cells could be detected in SIV-infected animals, compared to approximately 30% in HIV-2-infected and 5-12% in uninfected monkeys. However, separation of PBMC into T cell subpopulations revealed striking differences in apoptosis between SIV- and HIV-2-infected macaques. In SIV-infected monkeys both CD4 and CD8 cells underwent apoptosis to a large extent. In contrast, in the HIV-2-infected macaques apoptosis was restricted to the CD8 cell compartment. The lack of apoptosis in CD4 cells of healthy HIV-2-infected macaques implies an important role for CD4 cell apoptosis in AIDS pathogenesis.

Animals↗
PubMed1996

Generation of monoclonal antibodies against human prion proteins in PrP0/0 mice.

BACKGROUND: Prion diseases belong to a group of neurodegenerative disorders affecting humans and animals. The human diseases include kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), and fatal familial insomnia (FFI). The pathogenic mechanisms of the prion diseases are not yet understood. Monoclonal antibodies provide valuable tools in the diagnosis, as well as in the basic research, of several diseases; however, monospecific antisera or monoclonal antibodies (mAbs) against human prion proteins were, until now, not available. MATERIALS AND METHODS: We have developed an immunization protocol based on nucleic acid injection into nontolerant PrP0/0 mice. DNA or RNA coding for different human prion proteins including the mutated sequences associated with CJD, GSS, and FFI were injected into muscle tissue. Mice were primarily inoculated with DNA plasmids encoding the prion protein (PRNP) gene and boosted either with DNA, RNA, or recombinant Semliki Forest Virus particles expressing PRNP. Hybridomas were then prepared. RESULTS: Different mAbs against human prion proteins were obtained, and their binding behavior was analyzed by peptide enzyme-linked immunosorbent assay, Western blot, immunofluorescence, and immunoprecipitation. Their cross-reactivity with prion protein from other species was also determined. Our mAbs are directed against four different linear epitopes and may also recognize discontinuous regions of the native prion protein. CONCLUSIONS: These antibodies should allow us to address questions concerning the nature of the prion protein as well as the initiation and progression of prion diseases. Moreover, these mAbs can now be used for the diagnosis of prion diseases of humans and animals.

Animals↗
PubMed1995

Prion disease associated with a novel nine octapeptide repeat insertion in the PRNP gene.

Some cases of spongiform encephalopathies are linked to mutations within the prion protein gene (PRNP). Repetitive octapeptide insertions of variable length in the PRNP gene are also associated with spongiform encephalopathies, mostly familial Creutzfeldt-Jakob disease (CJD). In this study we report on a novel insertion mutation comprising nine extra octapeptide repeats between codons 51 and 91 of the PRNP gene. The affected patient showed a slowly progressive dementia of at least 6 years duration and ataxia.

Adult↗
PubMed1995

Cellular immune response of rhesus monkeys infected with a partially attenuated nef deletion mutant of the simian immunodeficiency virus.

To date the vaccines most successful in the simian immunodeficiency virus (SIV) model of AIDS are live attenuated viruses. However, the virus-specific immune response induced after infection of monkeys with attenuated SIV has not been described comprehensively. Therefore, we investigated the cellular immune response of eight rhesus macaques infected with a nef deletion mutant of SIVmac32H (pC8). In contrast to monkeys infected with pathogenic SIV, pC8-infected macaques developed a virus-specific T-cell proliferation. In addition, all animals showed a proliferative T-cell response to recall antigen and mitogens. In six of eight monkeys virus-specific cytotoxic T-cells directed against different SIV polypeptides were detected. In two animals, however, the truncated nef gene reverted to full length 12 weeks after pC8 infection. These two monkeys developed hematological alterations, indicating an immunodeficiency. Simultaneously with the onset of disease the animals lost their T-cell responsiveness against recall antigens. Eight weeks later their T-cell reactivity against mitogens was also abrogated. The results indicate that live attenuated SIV induced a virus-specific cellular immune response in monkeys which might be associated with the previously reported resistance to superinfection with pathogenic SIV. Paradoxically, if the attenuated SIV reverts in vivo to a more virulent virus, the SIV-specific immune response was inefficient to prevent the onset of immunodeficiency in the animals.

Animals↗
PubMed1995

Detection of infectious hepatitis A virus in blood factor concentrates by experimental infection of the New World primate Saguinus fuscicollis.

At present, the hepatitis A virus cannot be detected readily by cell culture techniques. However, the New World primate Saguinus fuscicolis is particularly susceptible to this virus. This paper gives details of the in vivo detection of hepatitis A virus in S. fuscicolis, and the method is used to show that a blood factor VIII preparation, suspected of being contaminated with hepatitis A, did not contain the virus.

Animals↗
PubMed1995

Repeated exposure of rhesus macaques to low doses of simian immunodeficiency virus (SIV) did not protect them against the consequences of a high-dose SIV challenge.

As part of an in vivo titration study of the macaque simian immunodeficiency virus (SIVmac) strain 251/spl, macaques were inoculated intravenously with various dilutions of this infectious SIVmac. Seven animals received dilutions from 10(-3) to 10(-6) of SIVmac251/spl. Two monkeys infected with the 10(-3) dilution of SIVmac exhibited a productive infection as indicated by seroconversion, detection of genomic RNA and proviral DNA and positive virus isolation. These animals showed a cytotoxic T cell (CTL) response against different SIVmac proteins without any measurable T cell proliferation. The five macaques receiving higher virus dilutions did not seroconvert and were negative for both viral RNA and for infectious virus, although proviral DNA was detected in their peripheral blood mononuclear cells. In contrast to the animals receiving the 10(-3) virus dilution, these five silently infected monkeys developed an SIV-specific proliferative T cell response but SIV-specific CTL could not be observed. The SIV-specific T cell proliferation of the silently infected animals could be boosted by a second low-dose exposure with a 10(-4) or 10(-5) dilution of SIVmac251/spl. The virological status of the animals was not changed following this second virus inoculation. Four months later these macaques were challenged intravenously with 2 ml of a 10(-4) dilution of SIVmac251/32H containing 10 monkey ID50. After this challenge all SIV-pre-exposed animals and three naive controls became productively infected. In addition, all infected animals developed typical signs of an immunodeficiency within 6 months after infection. These observations indicate that macaques infected silently by a low-dose exposure to infectious virus generated a virus-specific cellular immune response. However, SIV-specific T cell proliferation alone could not protect the monkeys against an intravenous challenge with SIVmac and the subsequent development of AIDS-like symptoms.

Animals↗
PubMed1995

Specificity of intrathecal IgG synthesis for HTLV-1 core and envelope proteins in HAM/TSP.

INTRODUCTION: In patients with human T-cell lymphotropic virus type 1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP), we investigated the significance of HTLV-1 specific antibodies in the cerebrospinal fluid (CSF). MATERIAL AND METHODS: The quantities of HTLV-1 specific immunoglobulin G (IgG) in paired CSF and serum were evaluated by a sensitive enzyme immunoassay (EIA). The specificity of antiviral IgG was determined by radioimmunoprecipitation of HTLV-1 antigens. RESULTS: In 17 of 20 HAM/TSP patients, quantitative evaluation by EIA supplied evidence for antiviral IgG synthesis within the CNS. Radioimmunoprecipitation demonstrated IgG antibodies against HTLV-1 envelope and core proteins in all HAM/TSP CSF and sera tested. Regarding the 3 sample pairs indeterminate in EIA for intrathecal synthesis, 2 showed stronger precipitation of HTLV-1 antigens by CSF IgG than by equal amounts of serum IgG. CONCLUSION: Intrathecal antibody synthesis specific for both HTLV-1 core and envelope antigens is common in HAM/TSP, thus providing conclusive evidence for an immune response to HTLV-1 within the CNS.

Antibody Specificity↗