Biomedical subjects

F J Kaup

Publications and source records attributed to F J Kaup.

At least 37 records · Page 2Linked to original sources

PubMed2000

Acute vascular rejection is associated with systemic complement activation in a pig-to-primate kidney xenograft model.

The introduction of h-DAF transgenic porcine organs into pre-clinical pig-to-primate discordant xenotransplantation has led to complete and reliable abrogation of hyperacute xenograft rejection (HAR). Despite additional heavy immunosuppression however, most xenografts are still lost due to acute vascular rejection (AVR), with current treatment protocols being of only limited value. In a life-supporting model of pig-to-primate kidney transplantation, unmodified (n=8) or h-DAF-transgenic (n=9) porcine kidneys were transplanted into cynomolgus monkeys under cyclophosphamide (CyP), cyclosporine and low-dose steroid immunosuppression. Longest recipient survival was 11 days in the control group and 68 days in the h-DAF transgenic group. Stable initial graft function with recipient survival >4 days was generated in eight animals (two controls and six transgenics). In these animals, plasma complement levels were analyzed during ongoing AVR. Compared with baseline levels, a two-fold increase in C3a levels and a four-fold increase in sC5b-9 levels were measured. In parallel to systemic complement activation, increased deposition of C3 and C5b-9 along with massive staining for recipient IgM immunoglobulins was detected in the xenografts on immunohistochemistry. We conclude that acute vascular xenograft rejection of porcine kidneys in cynomolgus monkeys is associated with classical pathway complement activation following binding of induced recipient anti-porcine antibodies. This complement activation can be observed despite membrane bound expression of human complement regulators in the porcine xenografts. Therefore, additional short-term fluid phase complement inhibition seems necessary for the future development of protocols designed for treatment of AVR in the pig-to-primate combination.

Acute Disease↗

PubMed2000

Long-term follow-up study on SIV intestinal proviral load in rhesus macaques.

After experimental infection with simian immunodeficiency virus (SIV), intestinal endoscopy proved to be an easily tolerated, minimal invasive procedure to obtain biopsies from the gastrointestinal tract of rhesus macaques during all stages of disease. As the GI tract is affected by many opportunistic infections and immunological impairment after SIV/human immunodeficiency virus (HIV) infection, knowledge on the proviral load is an important parameter for a better understanding of disease pathogenesis. In this paper, we describe the set-up and evaluation of a quantitative competitive polymerase chain reaction (PCR) and the quantification of SIV intestinal proviral load in a long-term follow-up study of eight rhesus monkeys (Macaca mulatta) after two different routes of virus inoculation. A SIV-specific signal could be detected as early as day 3 after infection. Of 143 biopsies from the follow-up study, 85.3% showed a positive PCR. DNA copy numbers ranged from 300 to 15,000 molecules per 100,000 cells. No significant influence of the inoculation route could be shown on either proviral load or survival time, but higher SIV proviral load was associated with a more rapid progression to disease. Therefore, the amount of proviral load in intestinal biopsies may be an important prognostic value for the further course of the disease.

Animals↗

PubMed1999

Rapid mucosal CD4(+) T-cell depletion and enteropathy in simian immunodeficiency virus-infected rhesus macaques.

BACKGROUND & AIMS: Human immunodeficiency virus (HIV) infection leads to severe immunologic and functional disturbances in the intestinal tract in late stages of the disease. Information on mucosal pathology directly after infection is limited. We characterized this early phase in rhesus macaques infected with simian immunodeficiency virus (SIV). METHODS: Eight rhesus macaques were infected with SIV. Upper endoscopy was performed at defined times before and after infection. Viral load, percentage of CD4(+) T cells, villus height, crypt depth, and Ki-67-positive crypt cells were analyzed in duodenal biopsy specimens. Serum beta-carotene and vitamin D levels were assessed. RESULTS: A rapid increase of duodenal SIV core protein (p27) concentration and an almost complete loss of intestinal CD4(+) T cells was found within 2 weeks after infection. A decrease of villus height was observed, and the percentage of Ki-67-positive (proliferating) crypt cells increased. Serum concentrations of vitamin D decreased in 6 of 8 animals, and beta-carotene concentrations decreased in 3 of 8 animals after infection. CONCLUSIONS: Mucosal SIV replication and intestinal CD4(+) T cell depletion are early events in SIV-infected rhesus macaques. The structural changes of the mucosa strongly support the concept of HIV/SIV-induced enteropathy. In contrast to late-stage human HIV infection, early small intestinal villous atrophy in SIV infection is associated with crypt hyperplasia.

Animals↗

PubMed1999

Morphologic and immunophenotypic characteristics of malignant lymphomas in SIV-infected rhesus macaques.

Eight cases of extranodal non-Hodgkin's lymphoma in simian immunodeficiency virus (SIV)-infected rhesus macaques, aged 4-9 years, were phenotypically and immunologically characterized, using the updated Kiel classification, in order to determine both the differences and the similarities between these types of lymphoma in immunodeficient rhesus macaques (Macaca mulatta) and man. The high-grade malignant tumors were of B-cell origin, with a predilection for extranodal growth in viscera and periorbital tissues. Immunophenotypical characterization showed that the monkey lymphomas were similar in many aspects to human immunodeficiency virus-associated lymphomas. The number of Ki67 positive cells varied from case to case and ranged from 50 to 90%. A serological screening for the simian equivalent of the Epstein-Barr virus (sEBV) by immunofluorescence assay revealed a prevalence of 92% of the sEBV antibodies in our cohort. The presence of Ebstein-Barr virus nuclear antigen (EBNA-2) could be demonstrated by immunohistochemistry in four out of eight cases. In situ hybridization revealed the presence of small EBV-encoded RNAs (EBER-1, EBER-2) in six of the eight cases. Further studies should define the precise role of herpesvirus infection for lymphomagenesis in SIV-induced immunodeficiency.

Animals↗

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↗

PubMed1999

Immunohistochemical studies of productive rhesus cytomegalovirus infection in rhesus monkeys (Macaca mulatta) infected with simian immunodeficiency virus.

In humans infected with the human immunodeficiency virus (HIV), clinical disease due to human cytomegalovirus (HCMV) infection is one of the AIDS-defining diseases; HCMV is the most common opportunistic infection found postmortem. Histologically, the typical lesions are characterized by "owl's eye cells." In rhesus monkeys infected with simian immunodeficiency virus (SIV), comparable lesions are caused by an infection with the rhesus CMV (RhCMV). The aim of this study was to investigate the incidence of productive and latent RhCMV infection in monkeys infected with SIV macaques (SIVmac). Eleven SIVmac-infected rhesus monkeys, which were euthanatized after developing AIDS-like disease, and 11 clinically healthy and uninfected animals comprised the study. The monkeys were screened serologically for RhCMV by western-blot analysis. Immunohistochemistry was performed by an indirect immunoperoxidase technique with a polyclonal rabbit RhCMV-antiserum. Lesions characteristic of RhCMV-associated diseases were detected histologically. All animals were latently RhCMV-infected. Seven of eleven (63.6%) SIV-infected macaques were productively RhCMV infected according to immunohistochemistry. RhCMV antigen was identified in the gastrointestinal tract, the hepatobiliary system, the lungs, and the testicles. Two of these seven animals showed characteristic inflammatory lesions associated with productive infection. Consequently, the CMV prevalence in SIVmac-infected rhesus monkeys and human AIDS patients is comparable.

Animals↗

PubMed1999

A case of intestinal Mycobacterium simiae infection in an SIV-infected immunosuppressed rhesus monkey.

Although Mycobacterium simiae was identified and classified more than three decades ago, only a few cases are mentioned in the current literature. After experimental simian immunodeficiency virus infection, a 9-year-old female rhesus monkey (Macaca mulatta) developed progressive immunosuppression and gastrointestinal disease very similar to the clinical and pathomorphologic features of Johne's disease, which is caused by M. paratuberculosis. Acid-fast-positive bacteria reacted immunohistochemically with antibodies against M. paratuberculosis and M. bovis but were not useful for differentiation because of a high degree of cross-reactivity. In contrast to immunohistochemistry and histopathology, biochemical methods and cycle sequencing analysis of the 16S ribosomal RNA identified M. simiae as the disease-causing pathogen. This case demonstrates the importance of molecular biological methods for the diagnosis of M. simiae infection in monkeys.

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

Association of simian immunodeficiency virus Nef with cellular serine/threonine kinases is dispensable for the development of AIDS in rhesus macaques.

The nef gene of simian immunodeficiency virus (SIV) is essential for high viral load and induction of AIDS in rhesus monkeys. A mutant form of the SIVmac239 Nef, which contains changes in a putative SH3-binding domain (amino acids 104 and 107 have been changed from PxxP to AxxA), does not associate with cellular serine/threonine kinases, but is fully active in CD4 downregulation and associates with the cellular tyrosine kinase Src. Infection of two rhesus macaques with SIVmac239 containing the mutant AxxA-Nef caused AIDS and rapid death in both animals. No reversions were observed in the majority of nef sequences analyzed from different time points during infection and from lymphatic tissues at the time of death. Our findings indicate that the putative SH3-ligand domain in SIVmac Nef and the association with cellular serine/threonine kinases are not important for efficient replication and pathogenicity of SIVmac in rhesus macaques.

Acquired Immunodeficiency Syndrome↗

PubMed1997

Intestinal manifestations of experimental SIV-infection in rhesus monkeys (Macaca mulatta): a histological and ultrastructural study.

Intestinal lesions were studied in 32 rhesus monkeys experimentally infected with different strains of simian immunodeficiency virus SIVmac (251/32H, 251/32H-SPL and 251/MPBL) by light microscopy, transmission and scanning electron microscopy. A spectrum of primary and secondary manifestations of SIV-infection were detected. Primary changes included 'SIV-enteropathy' in 12 monkeys and virus-induced syncytial giant cell formation (GCF) of the intestine in two animals. A primary virus-induced enteropathy occurred both as only histologically visible 'SIV-enteropathy' and as 'AIDS-enteropathy' accompanied by clinical signs of enteritis. Secondary opportunistic infections (Balantidium coli, Cryptosporidium, Trichuris, Trichomonas, Spironucleus, Mycobacteria and Cytomegalovirus) were identified in 27 animals and three monkeys developed malignant lymphomas involving the intestinal tract. Compared to intestinal lesions in HIV-infected patients, differences were found concerning the incidence of GCF and the range of opportunistic infections, with cryptosporidium, cytomegalovirus and mycobacteria occurring in both SIV-infected macaques and AIDS patients. The present observations revealed that SIV-infected rhesus monkeys provide an excellent model both for studies on the pathogenesis of HIV-enteropathy and opportunistic infections and for the development of therapies against cryptosporidial, cytomegalovirus and mycobacteria infection. Comparison of three SIV-strains revealed differences in primary and secondary lesions observed: SIVmac251/MPBL was correlated with severe primary SIV-induced pathologic changes and SIVmac251-SPL-infected animals showed a higher incidence of malignant lymphomas.

Animals↗

PubMed1997

[Herpesvirus infections in free living black tufted ear marmosets (Callithrix penicillata, E. Geoffroyi 1812) at the State Park of Serra da Tiririca, Niterói, Rio de Janeiro, Brazil].

The mortal cause of black-tufted-ear marmoset (Callithrix penicillata), living in a conservation unit of State Park of Serra da Tiririca-Niterói-RJ, Brasilien, has been investigated in 1995 based on different examinations realized in one animal. After clinical, light and electron microscopic investigations, herpesvirus infection was found to be the etiological agent of the disease.

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

Rapid development of vaccine protection in macaques by live-attenuated simian immunodeficiency virus.

Convincing data on experimental vaccines against AIDS have been obtained in the simian immunodeficiency virus (SIV) macaque model by preinfection with a virus attenuated by a nef deletion. To investigate the efficacy of a nef deletion mutant of SIVmac32H called pC8 as a live-attenuated vaccine after shorter preinfection periods and to learn more about the nature of the immune protection induced, eight rhesus monkeys were infected intravenously with the pC8 virus. All monkeys became persistently infected, exhibiting low cell-associated viral loads, but strong cellular and, in terms of binding antibodies, strong humoral antiviral responses. Two of eight pC8-infected monkeys developed an immunodeficiency and were not challenged. Sequence analysis of their nef revealed complete replenishment of the deletion. The other six monkeys, two preinfected for 42 weeks and four for 22 weeks, were challenged with pathogenic spleen-derived SIV. Complete protection was achieved in four vaccinees. Virus was consistently detected in two vaccinees from the 22-week-group challenge, however, they remained clinically healthy over a prolonged period. Protection from challenge virus infection or a delayed disease development seemed to be associated with a sustained SIV-specific T helper cell response after challenge. Thus, a sterilizing immunity against superinfection with pathogenic SIV can be induced even after a relatively short waiting period of 22 weeks. Nevertheless, such a vaccine raises severe safety concerns because of its potential to revert to virulence.

Animals↗

PubMed1996

Morphological characteristics of the ileal Peyer's patches in the rhesus macaque: a histological and ultrastructural study.

Ileal Peyer's patches of rhesus macaques were investigated by light and electron microscopy (scanning-electron microscopy, transmission-electron microscopy). The results were compared with findings in other species. Differences were found concerning the shape of the dome area, the composition of the dome epithelium and the apical membrane of M cells: in the rhesus monkey, hemispherical domes bulge into the intestinal lumen. The dome epithelium is composed of three populations of gut epithelial cells; absorptive enterocytes as the predominant cell type; goblet cells; and M cells ("microfold bearing' or "membraneous' gut epithelial cells). The apical membrane of M cells forms irregular protrusions.

Animals↗

PubMed1996

Ultrastructure of pre- and postcolostral enterocytes of the newborn calf.

Ten calves were used to elucidate the ultrastructure of enterocytes before and 24 h after colostral intake. Tissue samples were obtained from duodenum, jejunum (5 locations) and ileum. Protein A-gold technique was applied to immunoelectron-microscopically demonstrate colostral IgA. The prominent feature of the precolostral enterocytes are intracytoplasmic vacuoles. The frequency of vacuoles increases from cranial jejunum to ileum and from the villi bases to the tips. The appearance of absorptive vacuoles after colostral administration correlates with the incidence of precolostral empty vacuoles. Bovine IgA was detected in absorptive vacuoles and within the intestinal lumen of postcolostral calves. In addition to a diffuse IgA labelling of most vacuoles, a few corresponding enterocytic vacuoles labelled inhomogenously or negatively. This study demonstrates morphologically that the main site of colostral absorption is the middle-to-caudal region of the small intestine. Immunoelectron microscopy of IgA labelling provides indications of a selective IgA absorption in addition to pinocytosis.

Animals↗

PubMed1996

Retinal detachment in horses.

Ten horses with partial or total retinal detachment were investigated using light and electron microscopy (TEM, SEM). Several lesions were observed and compared with normal retinal morphology. Three weeks after the initial retinal detachment, hypertrophy of the pigment epithelium with transformation of the apical microvilli could be observed. The lesions were accompanied by progressive degeneration and atrophy of the sensory retina, starting at the photoreceptor outer segments. Hypertrophy of Müller cells was a concomitant finding. Retinal detachment represents a sequel either to inflammatory processes or trauma.

Animals↗

PubMed1996

Cyclic angiogenesis and blood vessel regression in the ovary: blood vessel regression during luteolysis involves endothelial cell detachment and vessel occlusion.

Angiogenesis occurs as a cyclically regulated process in the ovary and the uterus. After ovulation, there is massive sprouting of blood vessels in the growing corpus luteum (CL) during the first third of the ovarian cycle. During luteolysis and for several weeks thereafter, all newly formed vessels regress. Here we have systematically analyzed regression of blood vessels during luteolysis to identify mechanisms of blood vessel regression. Blood vessel counts are highest in the midcycle CL and drop rapidly after the onset of luteolysis. After a rapid phase of tissue dissociation, blood vessel regression proceeds slowly over several weeks in the residual CL. Endothelial cells in regressing vessels acquire a distinctly rounded and condensed phenotype. Ultrastructural analysis of blood vessel regression processes in the cyclic CL suggests two major mechanisms of blood vessel regression: a) detachment of rounded endothelial cells from their basement membrane, leaving areas devoid of covering endothelial cell monolayer, and b) contraction and occlusion of arterioles and small arteries with pronounced proliferation of smooth muscle cells. In situ detection of nucleosomal fragmentation products demonstrates numerous apoptotic luteal cells, but only a few apoptotic endothelial cells in the regressing CL. Induction of apoptosis in cultured endothelial cell monolayers by RGD peptides demonstrated that endothelial cells detach from their adhesive surface before fully becoming positive for nucleosomal fragmentation products. These data indicate that cyclic angiogenic processes in the ovary offer a suitable experimental system to analyze mechanisms of blood vessel growth and regression, and suggest that detachment of endothelial cells before apoptosis as well as contractive occlusion of blood vessels may be critical determinants of blood vessel regression.

Animals↗