Biomedical subjects

E Castaños-Velez

Publications and source records attributed to E Castaños-Velez.

16 recordsLinked to original sources

PubMed2000

Abolished angiogenicity and tumorigenicity of Burkitt lymphoma by interleukin-10.

Because of its immunosuppressive properties, interleukin-10 (IL-10) is thought to play an important role in a number of human disease states, including inflammation, autoimmunity, and transplant rejection. In this study, we demonstrate that introduction of human or viral IL-10 genes into Burkitt's lymphoma cells markedly reduced their ability to grow as subcutaneous (sc) tumors in SCID mice. In vivo assays for angiogenesis revealed an inhibition of the angiogenic capacity of the IL-10-transfected lines. Recombinant human IL-10 abolished and viral IL-10 reduced vascular endothelial growth factor (VEGF)-165-induced neovascularization. Furthermore, IL-10 blocked the VEGF- and fibroblast growth factor (FGF)-2-induced proliferation of microvascular endothelial cells in vitro. The current observations suggest a direct role for IL-10 in the prevention of angiogenesis in human lymphoid malignancies.

Animals↗

PubMed2000

Protective DNA immunization against Chlamydia pneumoniae.

We have investigated the efficacy of the DNA vaccination using the heat shock protein 60 (HSP-60) gene of C. pneumoniae, for protection of mice against infection with the bacteria. C57Bl/6 mice had a 5-20-fold reduction of C. pneumoniae numbers in lungs when immunized intranasally (i.n.) with plasmids (p) encoding pHSP-60. The reduction of the bacterial load coincided with a decreased severity of disease. No specific antibodies were detected after protective i. n. immunization. In contrast, mice immunized intradermally (i.d.) were not protected against challenge with C. pneumoniae, although specific humoral Immunoglobulin (Ig)G responses were generated. Co-inoculation i.n. of pHSP-60 with pIL-12 but not with pGM-CSF further increased protection of mice against infection with C. pneumoniae. Lungs from pHSP-60 i.n. immunized and infected mice showed higher levels of interferon (IFN)-gamma mRNA, and spleen cells from these mice co-cultured with r-HSP-60 released higher levels of IFN-gamma and displayed higher proliferative responses than nonimmunized and infected controls. pHSP-60 immunized IFN-gamma receptor (R)-/- mice were not protected against infection with C. pneumoniae. Likewise, i.n. administration of pIFN-gamma alone induced significant protection. DNA vaccine-induced protection was CD4+ and CD8+ T-cell dependent, as shown by DNA-vaccination of MHC class II-/-, CD4-/-, CD8-/- and CD4-/-CD8-/-mice. Interestingly, DNA vaccine induced CD4+ T cells, in the absence of CD8+ T cells, were involved in worsening the outcome of infection. This worsening was linked with a shift towards a Th2 cytokine pattern.

Animals↗

PubMed1999

Fetal porcine islet-like cell clusters transplanted to cynomolgus monkeys: an immunohistochemical study.

BACKGROUND: The mechanism(s) involved in acute cellular xenograft rejection have hitherto been generated in vitro or in different experimental models, with pig tissue being transplanted to rodents. There is an urgent need to validate these results in a clinically more relevant combination of species. METHODS: Fetal porcine islet-like cell clusters (ICC) were transplanted under the kidney capsule in cynomolgus monkeys, either untreated or given immunosuppression with cyclosporine (CsA; 10 mg/kg body weight, intramuscularly) and 15-deoxyspergualin (DSG; 5 mg/kg body weight, intramuscularly). ICC xenografts were examined at 1, 3, 6, or 10-12 days after transplantation, using immunohistochemical techniques. Serum levels of xenoreactive antibodies were measured with ELISA. RESULTS: No deposits of IgM, IgG, Clq, or C3 were detected within the ICC xenograft in any of the monkeys. Likewise, no significant increase in the levels of xenoreactive antibodies were found after transplantation. In untreated animals, a few N-Elastase-positive cells (neutrophil granulocytes) were seen in the xenograft at day 1. A few mononuclear cells were present in the adjacent renal parenchyma, but they did not infiltrate the xenograft. At this time (day 1), early signs of necrosis were observed in the central parts of the graft. On day 3, the graft had a large, central necrotic area that contained polymorphonuclear cells; the remaining parts of the xenograft showed severe infiltration with CD8+ T cells. Occasional CD68+ cells (macrophages) were seen on days 1 and 3. On day 6, large numbers of macrophages were found infiltrating the entire graft. A few CD20+ B cells, accumulated as small clusters, were also found. Only a few natural killer cells (CD56+) were detected. The CsA/DSG-treated monkeys showed markedly fewer CD2+/CD8+ T cells on day 6 than the untreated monkeys, and the ICC graft was clearly better preserved. However, the number of CD8+ and CD68+ cells had increased considerably at 12 days after transplantation and diffusely infiltrated the whole ICC xenograft. CONCLUSION: Porcine ICC transplanted under the kidney capsule in cynomolgus monkeys were rejected by an acute cell-mediated rejection progressing during the first 6 days after transplantation. The process was not dependent on host Ig or C3 binding to the graft. Although the rejection of porcine ICC was significantly delayed in CsA/DSG-treated monkeys, the ICC xenografts were almost completely destroyed 12 days after transplantation.

Animals↗

PubMed1999

Lymphoid disorders associated with HHV-8/KSHV infection: facts and contentions.

Following the demonstration in 1994, that Kaposi's sarcoma (KS) was associated with a novel virus (KSHV or HHV-8) belonging to the lymphotropic herpes family, this virus was also found in certain lymphoid neoplasias of immunodeficient (HIV+) and immune competent hosts. The association of HHV-8/KSHV infection is now well established with primary effusion lymphoma (PEL) or body cavity based lymphoma (BCBL) and multicentric Castleman's disease (MCD) of the plasma cell type. A possible pathogenic role of HHV-8/KSHV in other lymphoid tumours including primary central nervous system lymphoma (PCNSL) and multiple myeloma (MM) as well as some atypical lymphoproliferations and sarcoidosis has also been suggested, but this is at present a controversial matter, or not confirmed. Several HHV-8/KSHV genes, including potential oncogenes, genes homologous to various cellular genes and growth factors have been incriminated in the pathogenesis of KS and PEL/BCBL, but a common pathogenic mechanism for the clearly diverse proliferations represented by PEL, MCD and KS is at present not evident.

Castleman Disease↗

PubMed1999

Antibacterial components in bronchoalveolar lavage fluid from healthy individuals and sarcoidosis patients.

Antibacterial peptides and proteins are an integral part of the epithelial defense barrier that provides immediate protection against bacterial invasion. In humans, alpha-defensins are mainly bactericidal effectors in circulating granulocytes, beta-defensin-1 is synthesized in epithelial cells, and LL-37 is produced in granulocytes but is also induced in skin epithelia during inflammation. To investigate the importance of these defense effectors in disease, we analyzed bronchoalveolar lavage fluid (BALF) for bactericidal activity. Antibacterial activity was found in BALF material from healthy individuals and sarcoidosis patients, with enhanced activity in BALF from the patients. The activity was present as several antibacterial components, of which we have so far characterized LL-37, lysozyme, alpha-defensins, and antileukoprotease. In addition, the antibacterial peptide LL-37 was located in alveolar macrophages, bronchial epithelial cells, and bronchial glands, suggesting that it has a defensive role in airway mucosa. In conclusion, the airway epithelium is protected by a complex antibacterial defense system. This is activated in sarcoidosis, and may explain why these patients seldom develop severe respiratory tract infections.

Adult↗

PubMed1998

Measles virus antigen in macrophage/microglial cells and astrocytes of subacute sclerosing panencephalitis.

In two patients with subacute sclerosing panencephalitis (SSPE) of 10 and 25 months duration we demonstrated by immunohistochemistry the presence of measles-virus nucleocapsid antigen (MVNA) in CD68+ cells and astrocytes of brain tissues. In both cases, CD68+ hematogenous monocyte/ macrophages and perivascular microglial cells (Mphi) were found infiltrating the brain parenchyma, and often partially or completely invested by perivascular reactive astrocytes expressing glial fibrillary acidic protein (GFAP). Mphi with cytoplasmic MVNA were often seen in the Virchow-Robin spaces and in close association with perivascular astrocytes, which often also contained MVNA+ intracytoplasmic inclusions. Reactive astrocytosis was more severe in the patient with long-standing illness, and a correspondingly elevated number of strongly GFAP+ MVNA+ or MVNA- perivascular binucleated astrocytes was observed. An uptake of MVNA+ cell debris by reactive astrocytes was evident in areas of white matter displaying extensive demyelination and necrosis. Taken together, these observations seem to indicate that the brain infiltration by Mphi carrying measles virus could represent one pathway of virus entry and dissemination in the central nervous system. Virus transfer to perivascular astrocytes via cell-to-cell contacts with infected macrophages is also suggested.

Antigens, CD↗

PubMed1998

Trypanosoma cruzi infection in tumor necrosis factor receptor p55-deficient mice.

Tumor necrosis factor receptor p55 (TNFRp55) mediates host resistance to several pathogens by allowing microbicidal activities of phagocytes. In the studies reported here, TNFRp55-/- mice infected with the intracellular parasite Trypanosoma cruzi showed clearly higher parasitemia and cumulative mortality than wild-type (WT) controls did. However, gamma interferon (IFN-gamma)-activated macrophages from TNFRp55-/- mice produced control levels of nitric oxide and killed the parasite efficiently in vitro. Trypanocidal mechanisms of nonphagocytic cells (myocardial fibroblasts) from both TNFRp55-/- and WT mice were also activated by IFN-gamma in a dose-dependent way. However, IFN-gamma-activated TNFRp55-/- nonphagocytes showed less effective killing of T. cruzi than WT control nonphagocytes, even when interleukin 1beta (IL-1beta) was added as a costimulator. In vivo, T. cruzi-infected TNFRp55-/- mice and WT mice released similar levels of NO and showed similar levels of IFN-gamma mRNA and inducible nitric oxide synthase mRNA in their tissues. Instead, increased susceptibility to T. cruzi of TNFRp55-/- mice was associated with reduced levels of parasite-specific immunoglobulin G (IgG) (but not IgM) antibodies during infection, which is probably linked to abnormal B-cell differentiation in secondary lymphoid tissues of the mutant mice. Surprisingly, T. cruzi-infected TNFRp55-/- mice showed increased inflammatory and necrotic lesions in several tissues, especially in skeletal muscles, indicating that TNFRp55 plays an important role in controlling the inflammatory process. Accordingly, levels of Mn2+ superoxide dismutase mRNA, a TNF-induced enzyme which protects the cell from the toxic effects of superoxide, were lower in mutant than in WT infected mice.

Animals↗

PubMed1996

Protection against mucosal SIVsm challenge in macaques infected with a chimeric SIV that expresses HIV type 1 envelope.

In a monkey model we used a chimeric SIV expressing the HIV-1 envelope gene (SHIV-4) as a live attenuated vaccine and a virulent SIVsm as a mucosal challenge. Four cynomolgus monkeys were inoculated intravenously with SHIV-4. Virus was repeatedly isolated from blood mononuclear cells of all four animals for 2 to 7 months after the inoculation of SHIV. All monkeys developed neutralizing antibodies to HIV-1 and high antibody titers to HIV-1 envelope glycoproteins. In contrast, no neutralizing antibodies to SIVsm were detected and cross-reacting antibodies to SIV envelope glycoproteins were demonstrable in low titers. Nine to 12 months after the SHIV inoculation the four monkeys and six naive control monkeys were challenged intrarectally with 10 monkey infectious doses of macaque cell-grown SIVsm. After a follow-up period of 1 year, two of four SHIV-infected monkeys were completely protected against SIVsm infection as shown by repeated negative virus isolations and negative polymerase chain reaction for SIV envelope DNA. One naive monkey that received blood from the two protected monkeys showed no signs of infection. The remaining two SHIV-infected monkeys showed an initial infection on challenge with SIVsm, but viral replication was thereafter suppressed. Cytotoxic T lymphocytes to SIV Nef and RT were demonstrable in one of four SHIV-infected monkeys before SIVsm challenge, but this monkey was not protected against SIV infection. All six control animals yielded virus repeatedly after SIVsm challenge and three of them showed declining CD4 cell counts. Thus, infection with SHIV expressing HIV-1 envelope could induce cross-protection against mucosal SIVsm challenge.

Acquired Immunodeficiency Syndrome↗

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

Increased expression and secretion of ICAM-1 during experimental infection with Trypanosoma cruzi.

In the present study we demonstrate that spleens and hearts from BALB/c mice infected with the virulent Tulahuén or the low virulent CA-I strains of Trypanosoma cruzi, contain substantially higher ICAM-1 transcripts than uninfected controls. ICAM-1 expression in heart cells was also increased in the protein level, as measured by flow cytometry, ELISA and immunohistochemistry. The adhesive receptor was observed not only on inflammatory cells but also on sarcolemma of cardiac myocytes from T. cruzi infected mice. ICAM-1 expression was higher during the acute phase than in the chronic phase of infection, and paralleled the density of inflammatory leukocytes. Elevated titres of soluble ICAM-1 (s-ICAM-1) were detected in sera from mice during the acute phase of infection with CA-I or Tulahuén parasites. Cytokines, including IFN-gamma, IL-1 alpha, IL-6 and TNF-alpha have been shown to modulate expression of ICAM-1. Spleens and hearts from mice infected with CA-I or Tulahuen strains showed increased accumulation of mRNAs specific for these cytokines, which peaked during the acute phase of infection. However, IFN-gamma activity was not necessary for ICAM-1 induction, as its levels were also increased during infection in IFN-gamma receptor knock-out (IFN-gamma R- ) mice. Upregulation of ICAM-1 expression might be a direct consequence of parasite infection, since its density on cell lines of different lineages was enhanced after 24 or 48 h of infection with T. cruzi.

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↗

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

Extracellular matrix proteins and integrin receptors in reactive and non-reactive lymph nodes.

The extracellular matrix (ECM) proteins collagen I, III and IV, laminin, fibronectin, vitronectin, thrombospondin, tenascin and their integrin receptors of the beta 1 and beta 3 subfamilies showed characteristic patterns of distribution in different compartments of non-reactive and reactive lymph nodes (human and monkey). This was particularly evident during development of germinal centres. Thus, ECM proteins (collagens, laminin, fibronectin and tenascin) were abundant in the interfollicular (T-cell rich) compartments of non-reactive as well as reactive lymph nodes. In primary follicles, collagen I, III and fibronectin were expressed but displaced by the expanding germinal centre during the formation of secondary follicles in reactive lymphoid tissues. The integrin subunits were mainly associated with endothelial cells and lymphoid cells in interfollicular areas, but were absent or only poorly expressed in primary as well as secondary follicles. Evidently the expression of ECM components and their integrin receptors is markedly down-regulated in the reactive, highly proliferative germinal centres.

Animals↗

PubMedDate not supplied

Role of nitric oxide in resistance and histopathology during experimental infection with Trypanosoma cruzi.

We analyzed the biological role of nitric oxide (NO) during murine Trypanosoma cruzi infection. Infection of mice with T. cruzi markedly increased NO synthesis. Administration of N-nitro-L-arginine methyl-esther (L-NAME) intraperitoneally or intragastrically diminished endogenous NO synthesis and resistance of mice to acute infection with three biologically different strains of T. cruzi. Mice protected against challenge with T. cruzi by transfer of T-cell-enriched populations from chronically infected animals, showed higher serum nitrate levels than controls non-transferred, or transferred, with T cells from non-immune mice. Administration of L-NAME abrogated transfer of resistance, suggesting NO participation in this process. Depletion of T cells from the transferred population abolished both protection and NO3- increase. On the contrary, mice chronically infected with T. cruzi showed no increased parasitemia or death upon treatment with L-NAME. The NO donor drug S-nitroso-acetyl-penicillamine was able to kill tissue culture or bloodstream trypomastigotes in vitro at biologically relevant concentrations. Conversely, NO appeared not to play a role in formation of inflammatory foci during T. cruzi infection, since infected mice treated with L-NAME showed no reduced inflammation.

Acute Disease↗

PubMedDate not supplied

Cytotoxic intraepithelial lymphocytes in colorectal polyps and carcinomas.

The frequency of intraepithelial lymphocytes (IEL) was investigated in 255 colorectal lesions: in 18 metaplastic polyps, in 159 tubular, serrated and villous adenomas, in 28 incipient adenocarcinomas and in 50 overt adenocarcinomas. > or = 21 IELs were found in 13.6% (12/88) of the adenomas with high grade dysplasia (HGD) but in none of the 18 metaplastic polyps, the 71 adenomas with low grade dysplasia (LGD), or the 50 overt adenocarcinomas. CD3-T, MHCII and TIA1 cell antigens were positive in IELs from tubular adenomas, villous adenomas, incipient carcinomas and overt adenocarcinomas. In the normal colorectal mucosa and in metaplastic polyps, CD3-T was positive whereas MHCII and TIA 1 were not expressed. On the other hand, Fas cell antigen was expressed in the normal mucosa and in metaplastic polyps but it was downregulated in neoplastic lesions. The upregulation of CD3-T, MHC class II molecules, and TIA 1 in IELs of neoplastic colorectal lesions suggests that they are activated and cytotoxic; however, they undergo apoptosis due to the downregulation of the FAS molecules.

Colon↗

PubMedDate not supplied

Immunohistochemical expression of extracellular matrix proteins and adhesion molecules in pancreatic carcinoma.

BACKGROUND/AIMS: Carcinoma invasion and metastasis in general involve multiple steps including dynamic changes in the composition and structure of extracellular matrix proteins and cell surface receptors. In the present study, the usually highly invasive carcinoma of the pancreas was investigated regarding the expression of various extracellular matrix proteins and their corresponding integrin receptors, as well as E-cadherin. METHODOLOGY: Phenotypic expression of various markers was investigated immunohistochemically in frozen sections of 16 pancreatic carcinomas and normal pancreatic tissue. RESULTS: An irregular and discontinuous deposition of type IV collagen and laminin in the basement membrane was found in cancer tissue and a pronounced desmoplastic reaction with deposition of type I, type III, and type IV collagen in the tumor stroma. In contrast, the noninvolved pancreas showed an intact basement membrane and a sparse stroma. The collagen type IV and laminin receptors alpha 2, alpha 3, and beta 1 integrin subunits were expressed on pancreatic cancer cells but not the alpha 6 integrin subunit normally present on epithelial cells, suggesting anchorage independence of the carcinoma cells. An increased capacity for cancer cell motility was suggested by the abundant expression of the "antiadhesive" extracellular matrix proteins, tenascin and vitronectin close to the cancer cells, and the expression of cell surface receptors such as alpha v (vitronectin-binding). Expression of the alpha 4 integrin subunit was also increased on cancer cells. CONCLUSIONS: The distribution of extracellular matrix proteins and the cell surface immune phenotype differed in pancreatic carcinoma as compared to normal pancreatic tissue. The present findings substantiate the notion that disseminated growth of highly malignant carcinomas of the pancreas reflects an invasive interaction of the tumor cells with extracellular matrix proteins of a well-established stroma. Similar findings were observed regardless of tumor histology and patient survival time.

Adenocarcinoma↗