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Biomedical subjects

P Biberfeld

Publications and source records attributed to P Biberfeld.

At least 55 records · Page 3Linked to original sources
PubMed1996

SIV infection of monkey spleen cells including follicular dendritic cells in different stages of disease.

Immunoaffinity enriched spleen follicular dendritic cells (FDCs), lymphocytes, and macrophages from SIVsm-inoculated cynomolgus monkeys (Macaca fascicularis) at different stages of disease were compared for latent and productive SIV infection. Analysis of FDCs by in situ hybridization, electron microscopy, and coculture assays indicated that comparatively high levels of virus were associated with the FDC fraction. Polymerase chain reaction (PCR) and RT-PCR results revealed that the levels for SIVpol DNA did not correlate with the level of env mRNA in the various cell subsets, suggesting differences in latency. Limiting dilution assays for spliced env mRNA showed a 10-100-fold higher amount of env mRNA in FDCs than in other spleen cell subsets early during SIV infection. At late stages of disease, the number of productively infected FDCs significantly decreased in parallel with a marked reduction of the FDC network and follicular involution. Our findings indicate that destruction of FDCs probably reflects a cytopathic effect of SIV and/or the activity of specific antiviral cytotoxic T lymphocytes.

Animals↗
PubMed1996

Intracellular co-localization of Trypanosoma cruzi and inducible nitric oxide synthase (iNOS): evidence for dual pathway of iNOS induction.

Evidence is presented from studies in vitro and in vivo for a dual pathway of inducible nitric oxide synthase (iNOS) induction during Trypanosoma cruzi infection, one of which is interferon (IFN)-gamma dependent and the other not. In vitro, the IFN-gamma-dependent iNOS induction decreases parasite multiplication, and is in vivo associated with protection. iNOS induced by this pathway mediated a high NO output and showed a diffuse, cytoplasmic immunostaining in IFN-gamma-activated macrophages in vitro as well as in cell infiltrates or infected tissues. Surprisingly, in such tissues, iNOS co-localized with parasite nests, and by immunoelectromicroscopy, iNOS was demonstrated on the parasite surface. iNOS co-localization with parasites was also seen in tissues from T. cruzi-infected IFN-gamma receptor (R) knockout mice suggesting an IFN-gamma-independent pathway of induction. However, no cytoplasmic iNOS was seen in inflammatory infiltrates of these tissues. IFN-gammaR(-/-) mice displayed a dramatically enhanced susceptibility to infection with T. cruzi, diminished accumulation of iNOS mRNA in skeletal muscle and spleen cells, and reduced release of NO and peroxynitrite. Expression of iNOS around intracellular parasites was also observed after infection of peritoneal macrophages or L-929 fibroblasts in vitro in the absence of other exogenous stimuli. A time-dependent NO release and enhanced accumulation of iNOS mRNA also was observed in infected peritoneal cells and fibroblasts. Cultured T. cruzi amastigotes, trypomastigotes, and epimastigotes were not labeled by the anti-iNOS antibodies and contained no iNOS mRNA, indicating that the iNOS detected actually originated from the mammalian cell. A pathogenic effect of low NO levels is suggested by the arresting effect of NOS inhibitors and the enhancing consequences of low concentrations of NO donors on intracellular parasite multiplication.

Animals↗
PubMed1996

Expression of adhesion molecules in endemic and epidemic Kaposi's sarcoma.

Spindle cells and vascular endothelium in nodular lesions of AIDS associated (epidemic) and endemic Kaposi's sarcoma showed similar immunohistochemical patterns of expression for cell adhesion molecules and extracellular matrix proteins. Spindle cells as well as endothelium also expressed both alpha 5 and alpha V integrin subunits and ICAM-1 suggesting a possible role for inflammatory cytokines in spindle cell formation. The spindle cell compartment was rich in collagen, laminin, fibronectin and tenascin suggesting an important reactive component in the evolution of Kaposi's sarcoma. The lack of thrombospondin expression in the spindle cells favours the contention that they could be transitional, proliferating cells of endothelial origin. Specific expression of tat protein was not seen suggesting minimal if any HIV replication in these lesions. Our findings suggest similar histopathogenetic mechanisms for endemic and epidemic Kaposi's sarcoma. The clinically more malignant features of most AIDS related cases may reflect an important effect of systemic and focal cytokines in HIV patients and possibly other cofactor(s), i.e. tat protein in the induction and growth of the lesions.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Polyomavirus-infected oligodendrocytes and macrophages within astrocytes in progressive multifocal leukoencephalopathy (PML).

Polyomavirus-infected oligodendrocytes and in some instances virus-carrying macrophages were demonstrated within the cytoplasm of astrocytes by double immunostaining of brain lesions in a case of PML following bone marrow transplantation. The infected oligodendrocytes and CD68+ cells were usually partially or completely invested by the cytoplasm of reactive and infected or noninfected giant pleomorphic astrocytes. By electron microscopy (EM), internalized infected oligodendrocytes were shown to release polyomavirus particles possibly infectious to the astrocytes. These observations seem to indicate that astrocytes in PML can become infected by direct contact with internalized infected oligodendrocytes and possibly also by virus-loaded macrophages. Correspondingly, astrocyte/oligodendrocyte/macrophage cell-to-cell interactions appear to play an important role in the pathogenesis of PML lesions.

Astrocytes↗
PubMed1996

Retrieval of leukocyte antigens in paraffin-embedded rat tissues.

We compared the immunohistochemical reactivity of various rat leukocyte antigens in frozen and paraffin-embedded thymus, spleen, abdominal lymph node, liver, and brain tissues of healthy Sprague-Dawley rats, fixed in various fixatives. Immune reactivity after fixation in Methacarn was superior to that of 4% neutral buffered formalin, a mercury-based fixative (B-5), or Carnoy. Microwave (MW) antigen retrieval (AR) enhanced antigen reactivity. Ten of the 11 leukocyte antigens studied could be retrieved in Methacarn-fixed, paraffin-embedded sections with a reactivity comparable to that obtained on frozen sections.

Animals↗
PubMed1996

Mucocutaneous manifestations in 22 consecutive cases of primary HIV-1 infection.

Twenty-two consecutive patients presenting with symptomatic human immunodeficiency virus 1 (HIV-1) seroconversion were studied. Most of the patients had a glandular fever-like illness. All patients had fever and pharyngitis, and eight of them also suffered from ulcers of the oral, genital or anal mucosa. Uniform skin eruptions were observed in 17 of the 22 patients. The exanthem consisted of varying numbers of macular or maculopapular lesions that were oval or rounded in shape, ranging from a few millimetres to 1 cm in diameter. The lesions were distributed on the upper thorax in all cases, and were particularly profuse in the collar region. The face, forehead and scalp were involved in most cases, but the eruption was sparse or absent at the periphery of the extremities. In the majority of patients, the exanthem appeared after 2 or 3 days of fever. The exanthem developed during the first day, persisted for 5-8 days, and then cleared concurrently with the general recovery of the patients. Histopathological studies of skin punch biopsy specimens from four patients showed a sparse lymphocytic cell infiltrate distributed around vessels of the dermal superficial plexus. The infiltrates predominantly consisted of equally represented T-helper/inducer and T-suppressor/cytotoxic cells. A vacuolar aberration of basal layer cells was found in two of the four cases studied histologically. The microscopic findings correspond to the histopathological patterns seen in toxicodermia and in the interface dermatitis of morbilliform viral exanthems. The exanthem is a frequent and characteristic sign of primary HIV infection, which is further indicated if mucosal ulcers are present.

Adolescent↗
PubMed1995

Heterogeneity of spindle cells in Kaposi's sarcoma: comparison of cells in lesions and in culture.

The immunophenotype of spindle cells in epidemic, endemic, and classic (sporadic) Kaposi's sarcoma (KS) lesions was defined by the demonstration of various cell markers and compared with that of KS-derived cell lines. No significant histological or immunophenotypic differences were observed between the three clinical types of KS at comparable stages. The spindle-cell compartment of the different KS types was composed predominantly of a mixture of proliferating CD45+/CD68+ bone-marrow-derived monocytes and TE7+/collagen+ fibroblastic cells with varying expression of EN4/PAL-E/CD31/CD34/CD36 endothelial-associated antigens and/or smooth-muscle-specific alpha-actin (alpha-actin). The latter cells appeared to represent transitional forms of fibroendothelial and fibromyocytic cells. The in vitro cultured KS-derived cell lines (KS-3, KS-6, and KS-8) expressed the fibroblastic antigen TE7 and smooth-muscle-specific alpha-actin but not leukocytic or endothelial-associated antigens consistent with the phenotype of fibromyoid spindle cells of primary lesions. Neither HIV antigen nor provirus DNA was demonstrable in the epidemic KS lesions. The observed heterogeneity of the spindle-cell compartment further substantiates the view that Kaposi's sarcoma, irrespective of clinical setting, expresses salient features more compatible with reactive, tumor-like lesion than clonal sarcoma.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Studies on the regulation and localization of 5-lipoxygenase in human B-lymphocytes.

Stimulated B-lymphocytes, isolated from patients with chronic lymphocytic leukemia of B-cell type (B-CLL cells) or from human tonsils, produced similar amounts of leukotriene (LT) B4 and 5-hydroxyeicosatetraenoic acid (5-HETE) as polymorphonuclear granulocytes. Unlike intact granulocytes or monocytes, human B-lymphocytes require calcium ionophore, exogenous arachidonic acid and an oxidative environment in order to produce 5-lipoxygenase products. Several thiol-reactive compounds such as N-ethylmaleimide, methyl methanethiosulfonate, azodicarboxylic acid bis[dimethylamide] (diamide) as well as hydrogen peroxide were all found to stimulate cellular leukotriene biosynthesis. Reverse transcriptase (RT)-PCR analysis demonstrated the expression of 5-lipoxygenase, 5-lipoxygenase-activating protein (FLAP) and LTA4 hydrolase mRNA in B-CLL cells. Western blot analysis demonstrated a band corresponding to the molecular size of FLAP in the B-CLL cell membrane. Furthermore, MK886, the FLAP-binding cellular leukotriene biosynthesis inhibitor, reduced both LTB4 and 5-HETE formation. Immunocytochemistry showed that 5-lipoxygenase was mainly localized in the nuclei of non-activated B-CLL cells, tonsillar B-lymphocytes and monoclonal B-cells. In contrast, neither human peripheral T-lymphocytes nor Jurkat cells were stained. These results suggest that 5-lipoxygenase and its products function in the nucleus of B-lymphocytes.

5-Lipoxygenase-Activating Proteins↗
PubMed1995

Local suppression of Epstein-Barr virus (EBV)-specific cytotoxicity in biopsies of EBV-positive Hodgkin's disease.

Epstein-Barr virus (EBV)-positive Hodgkin's and Reed-Sternberg (HRS) cells express the virus-encoded latent membrane proteins LMP1 and LMP2 that could serve as rejection targets in Hodgkin's disease (HD). To examine whether EBV-triggered reactivities can be detected in the tumor, we have compared cytokine mRNA expression, cell phenotype, and cytotoxic activity in biopsies from 8 EBV-carrying and 6 EBV-HD patients. Neither the pattern of lymphokine production nor the cell phenotype of the in vivo-activated interleukin-2-responding populations provided a clear discrimination between EBV+ and EBV- cases. HLA class I-restricted EBV-specific cytotoxicity was shown in interleukin-2-dependent cultures from 3 of 3 EBV- tumors, whereas cultures from 6 of 6 EBV+ tumors were either noncytotoxic or exerted LAK-type cytotoxicity. EBV-specific cytotoxic T lymphocyte precursors were present in the blood of 1 patient carrying an EBV+ tumor. The results suggest that a tumor-associated suppression of EBV-specific T-cell responses may play an important role in the pathogenesis of EBV+ HD.

Adult↗
PubMed1995

Parallel existence of Epstein-Barr virus (EBV) positive and negative cells in a sporadic case of Burkitt lymphoma.

In the Burkitt lymphoma line Oma-BL1, EBV positive and negative cells coexist. We demonstrate that EBV positive and negative subclones are identical with respect to chromosome markers and HLA type and that the same c-myc rearrangement occurs in all the subclones. This shows that the tumor cells are derived from the same patient and are of monoclonal origin. In the positive subclones, the EBV genome was stably maintained in the episomal form. The EBV negative subclones could be derived from previously uncloned tumor cells in early passage, but not from the EBV positive subclones.

Adolescent↗
PubMed1995

B-cell lymphomagenesis in SIV-immunosuppressed cynomolgus monkeys.

B-cell lymphomas developed frequently (approx. 40%) in SIVsm (SMM3) immunosuppressed monkeys and were mostly extranodal, aggressive and all associated with an EBV-related simian herpes virus operationally designated herpes virus Macaca fascicularis (HVMF-I). Lymphoma tissues from 21 monkeys were studied by PCR and DNA PAGE for mono/oligoclonality of the VDJ-rearranged IgH genes. Most lymphomas (n = 15) showed a monoclonal and approximately 1/3 (n = 6) an oligoclonal VDJ rearrangement pattern. The time after infection to tumor presentation was significantly shorter for oligoclonal than for monoclonal lymphomas, suggesting that oligoclonal selection frequently precedes the outgrowth of a single malignant clone. Comparison of the VDJ rearrangements in an established lymphoma cell line and the original, oligoclonal lymphoma tissue indicated in vitro selection of one HVMF-infected clone. Longitudinal studies of sequential lymph-node biopsies showed that the malignant lymphoma clone in 3 out of 8 lymphomas could be identified as a predominant clone in lymph nodes 2-12 months after SIV infection and 6-10 months before clinical presentation of the lymphomas. VDJ-rearranged DNA corresponding to that of the lymphomas was also detected in most sera at the time of lymphoma manifestation but not in corresponding PBL preparations. Clearly, the SIVsm AIDS model in cynomolgus monkeys represents a powerful tool for biological and clinical studies of herpes-virus-associated lymphomagenesis in immunosuppressed states.

Animals↗
PubMed1995

Thymic immunopathology and progression of SIVsm infection in cynomolgus monkeys.

Thymuses from 22 cynomolgus monkeys infected with simian immunodeficiency virus (SIVsm) developed characteristic cortical and medullary changes including formation of B-cell follicles (8/21) and accumulation of virus immune complexes. Advanced thymic histopathology was correlated with more pronounced immunodeficiency. SIVsm provirus was detected by polymerase chain reaction (PCR) in most (16/18) thymuses and spliced viral env mRNA in 3 (3/7) thymuses with advanced histopathologic changes indicative of thymic SIVsm replication. By combined in situ hybridization (ISH) and immunohistochemistry, viral RNA was localized mainly to the follicular dendritic network, macrophages, multinucleated giant cells, and lymphocytes of the medullary regions. Latent infection by an Epstein-Barr-related herpesvirus (HVMF1) was also found by PCR and by ISH in medullary regions of three (3 of 8) thymuses with B-cell follicles, suggestive of an inductive role for B-cell proliferation in these thymuses. In a control group of HIV-2-infected nonimmunosuppressed monkeys, no comparable thymic changes were observed. Our results indicate that SIV, and probably by analogy HIV, can have direct and diverse pathogenic effects on the thymus that are important in the development of simian (human) AIDS.

Animals↗
PubMed1995

Intracerebral inflammatory response to experimental brain contusion.

The inflammatory reaction following experimental brain contusion was studied by immunohistochemistry in 22 rats during the first 16 days after trauma. An inflammatory mononuclear cell response was evident on day 2, with a maximum on days 5-6 and signs remained still 16 days after the trauma. The time course of the cellular infiltration adjacent to the lesion correlated with blood brain barrier dysfunction in the contralateral side of the traumatized hemisphere. The cellular infiltrate comprised NK cells, T-helper cells and T-cytotoxic/suppressor cells as well as monocytes/macrophages. Most of the macrophages appeared to be activated by T-cells. Surprisingly, polymorphonuclear cells appeared less engaged than mononuclear cells in the inflammation. The demonstration of immunocompetent cells and the induction of MHC-1 and MHC-II antigen provides a substrate for inflammatory reactions similar to those that cause neurological damage in inflammatory diseases such as viral infections, multiple sclerosis and experimental allergic encephalitis. Our observations indicate that the role of the inflammatory reactions may have a role, hitherto neglected, in the pathogenesis of secondary traumatic brain injury.

Animals↗
PubMed1995

Epstein-Barr virus (EBV) DNA in saliva and EBV serology of HIV-1-infected persons with and without hairy leukoplakia.

Secretion of Epstein-Barr virus (EBV) in saliva, as well as serum antibody titres against various EBV antigens, were analyzed in respect of (1) 15 HIV-1-infected patients with oral hairy leukoplakia proven to contain EBV by in situ hybridization, (2) 45 HIV-1 infected patients without hairy leukoplakia, (3) 10 HIV-1 infected patients treated with acyclovir or foscarnet and (4) 21 healthy controls. The numbers of CD4+ cells in the peripheral blood were also recorded. The HIV-1 infected patients were at various stages of HIV-1-associated disease. Excretion of EBV DNA in the saliva was determined by means of the polymerase chain reaction (PCR) while the amount of EBV DNA in positive samples was estimated by repeated titrations. The frequency of shedding of EBV DNA increased from 33% in healthy controls to 78% in asymptomatic HIV-1 infected persons, but did not increase significantly with progression of HIV-1-associated disease. The titres of EBV DNA in saliva correlated inversely and significantly with the number of CD4+ cells in the peripheral blood. All patients with hairy leukoplakia shed by EBV DNA in their saliva but the titres were not significantly higher than those of other HIV-1 infected persons. The serum titres of antibodies against EBV nuclear antigen 1 (EBNA-1) correlated positively and significantly with the CD4+ cell count in the peripheral blood. EBNA-1 IgG antibody in the serum was also significantly lower in symptomatic than in asymptomatic HIV-1 infected persons. There were, however, no significant differences in serum antibodies to various EBV antigens between patients with and without hairy leukoplakia.

Acquired Immunodeficiency Syndrome↗
PubMed1995

A role for a new herpes virus (KSHV) in different forms of Kaposi's sarcoma.

Kaposi's sarcoma (KS) is a previously rare, tumour-like lesion of controversial biological nature. KS has since the early 1980s become frequent in patients with AIDS, particularly in homosexuals. KS is also endemic in Central Africa predominantly in otherwise healthy men but also in women and children. Recently, evidence for the presence of novel, herpes virus DNA sequences in more than 90% of AIDS Kaposi lesions (AKS) was presented. This DNA was identified using representational difference analysis (RDA) generating short, unique sequences with variable homology to several herpes virus, but no intact virus was recovered. If these DNA-sequences are also present in other, non-HIV-associated forms of Kaposi's sarcoma this would strongly suggest a specific, aetiopathological involvement of this putative new herpes virus in the pathogenesis of Kaposi's sarcoma, rather than a contamination of yet another opportunistic virus in immunosuppressed AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Long-term protection against SIV-induced disease in macaques vaccinated with a live attenuated HIV-2 vaccine.

The aim of this study was to test the ability of a live attenuated human immunodeficiency virus type 2 (HIV-2) vaccine to protect cynomolgus monkeys against superinfection with a pathogenic simian immunodeficiency virus (SIVsm). This report is an update on our previously reported observation period of nine months. The new data here show that three of four monkeys vaccinated with live HIV-2 were protected against immunosuppression and SIV-induced disease during more than five years of follow-up. The quality of the immunity was permissive for infection, but monkeys that survived showed restricted viral replication in peripheral blood and lymph nodes. This study shows that it is possible to induce protection against a pathogenic heterologous primate lentivirus and to prevent disease in vaccinated monkeys even if infection is not prevented. These findings provide evidence that protection against AIDS can be achieved by immunization.

AIDS Vaccines↗