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M R Capobianchi

Publications and source records attributed to M R Capobianchi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Human immunodeficiency virus type 1 gp120 stimulates cytomegalovirus replication in monocytes: possible role of endogenous interleukin-8.

Recombinant gp120, but not other human immunodeficiency type 1 (HIV-1) structural proteins, dose-dependently stimulates human cytomegalovirus (HCMV) immediate-early antigen (IEA) expression and infectious virus yield in freshly isolated normal monocytes infected with HCMV. Monoclonal antibodies (MAbs) recognizing the gp120 V3 loop, as well as V3 loop octameric multibranched peptides and antibody to galactocerebroside, but not sCD4, abrogate the gp120 stimulation of IEA expression, suggesting that the effect involves V3 loop-galactocerebroside interaction and is not mediated by CD4. Interleukin 8 (IL-8) gene expression is enhanced in monocytes treated with gp120 at the level of both mRNA and released protein. Exogenous IL-8 could replace gp120 in the stimulation of HCMV infection, while a MAb capable of neutralizing IL-8 activity abrogates the gp120-induced HCMV stimulation. These data indicate that HIV-1 glycoprotein induces stimulation of productive infection of monocytes with HCMV and that such stimulation may be mediated by the upregulation of IL-8 gene expression. This is the first evidence that HIV-1 may affect HCMV replication indirectly, via the interaction of gp120 with the monocyte membrane, in the complete absence of retroviral replication, through the stimulation of IL-8 release. Because in HIV-1-infected individuals, HCMV infection is frequently activated and the levels of circulating IL-8 are enhanced, these findings may be pathogenetically relevant.

Antigens, Viral↗
PubMed1996

Interferon induction by HIV-1-infected cells: a possible role of sulfatides or related glycolipids.

We have investigated the mechanism of interferon (IFN) induction in peripheral blood mononuclear cells by HIV-1(IIIB)-infected H9 cells or by recombinant gp120. A monoclonal antibody specific for the galactosylsphingosinyl moiety in galactocerebrosides and sulfatides inhibited IFN induction in a dose-dependent manner. Furthermore, exogenous sulfatides inhibited with an ID50 of approximately 1 microM, whereas galactocerebrosides were not inhibitory at 40 times higher concentrations. These studies suggest that sulfate containing galactolipids such as sulfatides on responder cells may be part of the gp120-membrane complex that initiates the induction of IFN. A partial homology of an epitope on the V3 loop of gp 120 with a previously suggested binding domain for sulfated glycoconjugates supports this conclusion.

Amino Acid Sequence↗
PubMed1996

Interferon gamma stimulates cell-mediated transmission of HIV type 1 from abortively infected endothelial cells.

Human umbilical vein endothelial cells (HUVEC) can be abortively infected with HIV-1, but virus production is rescued by T cells. The influence of interferon gamma (IFN-gamma) in this experimental system has been investigated. HUVEC either untreated or treated with IFN-gamma were infected with HIV-1 and cocultivated with rescuer T cells. Virus yield was subsequently assessed as antigen or infectivity present in the cocultures supernatants. Viral DNA in HUVEC was detected by polymerase chain reaction. Transmission electron microscopy was used to establish direct interactions between HUVEC and T cells. Intercellular adhesion molecule (ICAM)-1 expression by HUVEC was measured by enzyme-linked immunoassay. Monoclonal antibodies (MAbs) to adhesion molecules were used to block the rescue of infection by T cells. Treatment of HUVEC with IFN-gamma caused a dose-dependent enhancement of HIV-1 yield in cocultures of HUVEC with either lymphoblastoid or normal T cells. IFN-gamma was effective also when administered to HUVEC 1 day after infection. Neither HIV-1 adsorption nor virus reverse transcription was stimulated by IFN. Physical contact between HIV-1-infected HUVEC and rescuer T cells was observed, and discrete tracts of discontinuity between the juxtaposed membranes were detected, being more frequent when HUVEC had been treated with IFN-gamma. Treatment with IFN determined an increase of ICAM-1 expression by HUVEC, and anti ICAM-1 MAbs inhibited HIV-1 rescue, being more effective when HUVEC had been exposed to IFN-gamma. Treatment of T cells with anti-LFA-1 Mab also inhibited HIV-1 rescue. The enhancing effect of IFN-gamma could be the result of stimulated transfer of HIV-1 infection from HUVEC to T cells, possibly mediated by enhanced expression of ICAM-1 by HUVEC, that could, in turn, enhance the efficiency of membrane interaction with T cells. Since in HIV-1-infected patients circulating IFN-gamma is enhanced, our results can have pathogenetic implications.

Antiviral Agents↗
PubMed1995

Antibody to ICAM-1 mediates enhancement of HIV-1 infection of human endothelial cells.

Human umbilical vein endothelial cells (HUVEC) can be abortively infected with HIV-1, but virus production is rescued by the addition of T cells. Monoclonal antibody (Mab) to ICAM-1, but not its Fab' fragment or MAbs to LFA-1 and PECAM-1, increases HIV-1 infection of HUVEC by enhancing HIV-1 absorption. Enhancement by anti ICAM-1 is probably due to a bridging effect different from the ADE mediated by anti-gp120 that involves FcR or CR-mediated capture of the virus-antibody complex. Since antibodies to cell membrane molecules are present in HIV-1 infected patients, the ADE mediated by such a mechanism can be important in AIDS pathogenesis.

Antibodies, Monoclonal↗
PubMed1995

Host cell antigenic profile acquired by HIV-1 is a marker of its cellular origin.

HIV-1 acquires cell membrane proteins during budding. The cell membrane proteins (CMP) profile of laboratory HIV-1 strains grown in different host cells was established, by using an immobilized antibody capture (IAC), to verify whether CMPs present on HIV-1 correlate with its host cell origin. HIV-1 grown in different cell lines incorporates cell markers such as CD3, CD19, CD14, CD31 and IL 2-R, according to the distinctive expression of these antigens on the host cells. Furthermore, also T-tropic and monocytotropic HIV-1 strains display host cell specific markers, supporting the hypothesis that virus associated CMPs are a marker of host cell origin.

Antigens, CD↗
PubMed1995

HIV type 1 grown on interferon gamma-treated U937 cells shows selective increase in virion-associated intercellular adhesion molecule 1 and HLA-DR and enhanced infectivity for CD4-negative cells.

Cellular adhesion molecules, such as ICAM-1, -2, and -3; LFA-1; and HLA class I and II are incorporated into HIV-1 virions during budding from infected cells. These virion-associated molecules can be involved in the adsorption to susceptible cells displaying the corresponding counterligands. A number of cytokines have been shown to upregulate the cellular expression of adhesion molecules, such as ICAM-1 and HLA-DR. In this study we investigated the effects of IFN-gamma on the incorporation of ICAM-1, LFA-1, and HLA-DR into mature HIV-1 progeny from chronically infected cells. The ability of such virus progeny to infect either CD4-positive or -negative cells was also investigated. The results indicate that IFN-gamma stimulates the expression of ICAM-1 and of HLA-DR on HIV-1-infected cells, whereas LFA-1 expression is unaffected. The same modifications were also observed on virus progeny, because specific MAbs to ICAM-1 and HLA-DR captured infectious HIV-1 from IFN-treated cells with higher efficiency as compared to virus from control cells, whereas virus binding to anti LFA-1 MAb was unchanged. Moreover, the HIV-1 progeny released from IFN-treated cells showed an increased ability to bind to and to infect CD4-negative cells, whereas the infectivity was basically unchanged for CD4-positive cells. Our results suggest that cytokines, as well as other soluble factors, may expand the host cell range of HIV-1, possibly through modifications of the cell-derived surface molecules on the virions.(ABSTRACT TRUNCATED AT 250 WORDS)

CD4 Antigens↗
PubMed1995

Induction of interleukin-10 by human immunodeficiency virus type 1 and its gp120 protein in human monocytes/macrophages.

In this study, we evaluated the effects of human immunodeficiency virus type 1 (HIV-1) and its gp120 protein on interleukin-10 (IL-10) expression in cultured human monocytes/macrophages. Infection of either 1-day monocytes or 7-day monocyte-derived macrophages with HIV-1 strain Ba-L resulted in clear-cut accumulation of IL-10 mRNA at 4 and 24 h. Likewise, treatment of these cells with recombinant gp120 induced IL-10 mRNA expression and caused a marked increase in IL-10 secretion. Monoclonal antibodies to gp120 strongly inhibited recombinant gp120-induced IL-10 secretion by monocytes/macrophages. Moreover, the addition of IL-10 to monocytes/macrophages resulted in a significant inhibition of HIV-1 replication 7 and 14 days after infection. On the whole, these results indicate that HIV-1 (possibly through its gp120 protein) up-regulates IL-10 expression in monocytes/macrophages. We suggest that in vivo production of IL-10 by HIV-primed monocytes/macrophages can play an important role in the early response to HIV-1 infection.

Base Sequence↗
PubMed1995

Unidirectional budding of HIV-1 at the site of cell-to-cell contact is associated with co-polarization of intercellular adhesion molecules and HIV-1 viral matrix protein.

OBJECTIVES: To explore the possibility that HIV-1 budding and cellular adhesion molecules co-polarize at cell-to-cell contact sites. To investigate the incorporation of host-cell-derived adhesion molecules into HIV-1. METHODS: The cellular sites involved in HIV-1 budding were examined by transmission electron microscopy. Single and double immunocytochemistry staining was used to evaluate the cellular distribution of the viral matrix protein and adhesion molecules. Quantitative flow cytometry was used to measure the cellular expression of adhesion molecules. An immunocapture technique was used to measure the presence of cell-derived proteins on HIV-1. The captured virus was measured by a p24 antigen assay. The infectivity of virus captured by monoclonal antibodies was tested by measuring the virus antigen yield in supernatants after the addition of sensitive cells. RESULTS: Released and budding HIV-1 was mainly localized at the cell-to-cell contact regions. This feature was consistent with a polarized staining for the virus matrix protein p18 at cell-to-cell contact regions. Intercellular adhesion molecules (ICAM)-1 in HIV-1-infected cells were polarized on both isolated cells and syncytia, co-localizing with HIV-1 matrix protein. HIV-1 incorporated all the adhesion molecules expressed by the host cells, although without quantitative correlation with their cellular expression. CONCLUSIONS: HIV-1 is released at cell-to-cell membrane contact sites. Both ICAM-1 and virus matrix protein co-polarized on isolated cells and syncytia at the sites involved in the recruitment of uninfected cells. The impressive concentration of ICAM at cell sites where most virions are released may account for the acquisition of these membrane proteins by the HIV-1 progeny, and may be important for the cell-mediated spread.

Antigens, CD↗
PubMed1994

Interferon induction by HIV glycoprotein 120: role of the V3 loop.

We have studied the mechanism of IFN induction by HIV-1 in peripheral blood mononuclear cells (PBMC), using recombinant viral membrane glycoproteins as potential inducers. Whereas 8 nM HIVIIIB-derived gp120 resulted in IFN levels between 80 and 2000 IU/ml with PBMC from different donors, gp120 from the MN strain was not an inducer. Preincubation of HIVIIIB-gp120 with a monoclonal antibody (mAB) to its CD4 binding domain or of PBMC with a mAB to the gp120 binding domain of CD4 abolished IFN induction. Antibodies against the third extracellular domain of CD4 which did not block binding of gp120, however, were also inhibitory. Furthermore, several mABs to the third variable loop (V3) of HIVIIIB-gp120 also blocked IFN induction, suggesting an important role of V3 in this process. This was further supported by the inhibitory action of peptides homologous to complete or partial sequences of V3. We conclude that after binding of gp120 to its CD4 receptor the V3 loop can be positioned close to the membrane of the responder cells by bending of gp120-occupied CD4 at its hinge region between extracellular domains 2 and 3. As a result V3 is able to interact with a V3-specific "secondary receptor" on the membranes of these cells. We suggest that it is the latter interaction which triggers IFN induction.

Amino Acid Sequence↗
PubMed1994

Interferon expression in Crohn's disease patients: increased interferon-gamma and -alpha mRNA in the intestinal lamina propria mononuclear cells.

The in vivo interferon (IFN) activation in Crohn's disease was evaluated by measuring the relative amounts of IFN-alpha and -gamma mRNA in freshly isolated human lamina propria mononuclear cells (LPMC) from patients with Crohn's disease and controls. Both IFN-gamma and IFN-alpha mRNA, as estimated by dot blot analysis, were increased in Crohn's disease (LPMC), although the relative amounts of IFN mRNA appeared to differ among patients. Appreciable amounts of IFN-gamma mRNA were found in Crohn's disease peripheral blood mononuclear cells (PBMC) extracts, whereas the same cells were negative for IFN-alpha mRNA. Only minute amounts of IFN-gamma RNA were found sporadically in control LPMC while no IFN-alpha was detected. Control PBMC were shown to be virtually negative for both IFN-alpha and IFN-gamma mRNA. These data suggest that IFN induction in the normal human gut is a well-controlled function and that in Crohn's disease tissues, both IFN-gamma and IFN-alpha production are dysregulated. The increased IFN activity may represent a major feature in the induction and perpetuation of the chronic inflammatory process in Crohn's disease.

Crohn Disease↗
PubMed1994

A simple and reliable method to detect cell membrane proteins on infectious human immunodeficiency virus type 1 particles.

Identification of cell-derived molecules on infectious human immunodeficiency virus type 1 (HIV-1) particles may be helpful in investigating mechanisms of HIV infection and in vaccine studies. Some of these molecules were detected on HIV-1 virions in previous studies, but rather elaborate methods were used. The method presented here allows an extensive characterization of the cell surface molecules associated with HIV-1 by capturing virus particles on monoclonal antibodies to cell membrane antigens bound to plastic wells. Binding of infectious virus was assessed by adding permissive target cells (C8166) and determining viral replication. With this procedure, beta 2-microglobulin, HLA-DR, intercellular adhesion molecule-1, and leukocyte function antigen-1 were found on HIV-1 particles from laboratory strains and primary clinical isolates. In contrast, CD19, CD4, and CD8 molecules were not detected.

Antigens, Surface↗
PubMed1994

Recombinant gp120 induces IL-10 in resting peripheral blood mononuclear cells; correlation with the induction of other cytokines.

Immunological abnormalities present in HIV-1-infected individuals often reflect an imbalance of cytokine production. The HIV-1 gp120 has the ability to induce a number of cytokines, and to enhance immunoglobulin release by normal peripheral blood mononuclear cells (PBMC) in vitro, in the absence of IL-2 production and of lymphoproliferation. This study provides evidence that gp120 is a potent IL-10 inducer in normal PBMC cultures. The pattern of other cytokines induced by gp120 includes interferon-alpha (IFN-alpha) and IFN-gamma, tumour necrosis factor-alpha (TNF-alpha), IL-6, IL-1 alpha and -beta, and not IL-2 and IL-4. These findings further define the pattern of cytokine release induced by gp120 on human resting PBMC. Furthermore, the present findings roughly parallel those observed both in the sera of patients and in the mononuclear cells from HIV+ individuals early after infection, suggesting that gp120 could be a good candidate as one of the agents responsible for cytokine dysregulation observed in HIV-1-infected individuals.

Biopterins↗
PubMed1994

Multinucleated giant cells generation induced by interferon-gamma. Changes in the expression and distribution of the intercellular adhesion molecule-1 during macrophages fusion and multinucleated giant cell formation.

BACKGROUND: Multinucleated giant cells (MGC), interferon-gamma (IFN-gamma) production, and increased expression of adhesion molecules are features of granulomatous reactions. IFN-gamma induces the fusion of macrophages and the subsequent MGC generation in vitro. Moreover, IFN-gamma increases ICAM-1 expression on lymphoid cells and an important role for adhesion molecules in MGC generation has been proposed. EXPERIMENTAL DESIGN: The time course of the IFN-gamma-driven MGC generation was investigated in slide-chamber cultures of adherence-purified human monocytes. The fusion index, the monocytes clustering the total number of MGC were determined. The expression of intercellular cell adhesion molecule-1 (ICAM-1), LFA-1 and HLA-DR was investigated by immunohistochemistry. The effect of anti-ICAM-1, anti-LFA-1 and anti-HLA-DR monoclonal antibodies on IFN-gamma-induced MGC generation was also examined. RESULTS: IFN-gamma enhanced the generation of MGC in a dose- and time-dependent fashion. In all experiments, MGC formation was preceded by a sequence of changes in the morphology of cultured monocytes. Cell clustering occurred as early as 3 days after IFN-gamma stimulation and was followed by the adhesion of cells that eventually fused. Immunohistochemistry showed that ICAM-1 was increased by IFN-gamma and constantly polarized on a cell uropode. When monocytes clustered, ICAM-1 was localized on the membrane where the cell-to-cell contact occurred. In newly formed MGC, ICAM-1 stained in the center of the giant cell. The cellular distribution of LFA-1 on cultured monocytes was not modified by IFN-gamma. HLA-DR expectedly enhanced by IFN-gamma was mostly cytoplasmic and tended to disappear when MGC formed. Finally, anti-LFA-1 and anti-ICAM-1 monoclonal antibodies variably inhibited IFN-gamma-induced MGC generation. CONCLUSIONS: Taken together, these data add support to the concept that IFN-gamma is essential for MGC generation by promoting cell clustering and cell-to-cell adhesion. The present data also indicate that among the mechanisms by which IFN-gamma exert such a promoting effect, changes in the ICAM-1 expression and cellular distribution are included. The observation that ICAM-1 appears to be trapped in the cytoplasm of IFN-gamma-driven MGC and that HLA-DR tend to disappear from macrophages undergoing MGC formation, also suggest changes in the functional properties of these cells.

Cell Fusion↗
PubMed1994

T cell growth-promoting activity of interferon-gamma. Mitogenic effect of the recombinant cytokine on cells from a human T-chronic lymphocytic leukemia.

Interferon-gamma (IFN-gamma) has previously been described as exerting a growth factor activity for murine and human stimulated normal T lymphocytes, in addition to its established role in regulating the cytotoxic activity of T and NK cells. We analyzed the effect of human recombinant IFN-gamma on the proliferation of leukemic lymphocytes isolated from the peripheral blood of a patient affected by a T-cell chronic lymphocytic leukemia (T-CLL). Incubation with IFN-gamma induced the proliferation of unstimulated leukemic cells. Cell proliferation was maximal after 6 days of culture with the cytokine; the half-maximal effect of IFN-gamma was observed at a concentration of approximately 800 U/ml. We also measured the production of IFN-gamma by leukemic cells. Cells incubated in control medium released small quantities of IFN-gamma activity, while the addition of low doses of the exogenous cytokine to the cell cultures induced high levels of IFN-gamma mRNA and protein production. Furthermore, anti-HLA class I monoclonal antibodies, that exert a mitogenic effect on these neoplastic lymphocytes, also induced the IFN-gamma gene expression in the same cells. These results indicate that IFN-gamma may stimulate the proliferation of human neoplastic T cells and suggest that this cytokine might have a role in the expansion of T-leukemic cell clones in vivo.

Antibodies, Monoclonal↗
PubMed1993

CD4-positive lymphoid cells rescue HIV-1 replication from abortively infected human primary endothelial cells.

Human primary endothelial cell cultures, derived from umbilical vein (HUVEC), can be infected by different strains of HIV-1, but mature virus production remains undetectable both in supernatants and in cellular extracts. Yet viral DNA is transiently detectable during the first days of infection, but progressively declines during the subsequent days. This finding is characteristic of abortive infections. Co-culture of HUVEC carrying HIV DNA with activated peripheral blood mononuclear cells or with CD4-positive lymphoid cells elicited a massive cpe (syncytia formation and cell degeneration) in the latter cells, caused by the establishment of productive HIV-1 infection. HUVEC infected in the presence of AZT were significantly impaired in the ability to transmit the infection of CD4-positive cells, indicating that active DNA synthesis is required in HUVEC before rescue by CD4-positive cells. These results are of interest in view of the possibility that endothelial cells can play a role in the transmission of HIV-1 infection from infected pregnant women to the foetuses, and, more generally, suggest a potential role of endothelial cells as a transient reservoir of HIV-1.

Antibodies, Monoclonal↗
PubMed1993

Coordinate induction of interferon alpha and gamma by recombinant HIV-1 glycoprotein 120.

Similarly to HIV-infected cells, recombinant HIV-1 glycoprotein 120 induces acid-labile interferon production in peripheral blood mononuclear cells from healthy donors. Acid lability of this interferon is due to the presence of both IFN-alpha and -gamma molecules. In fact, although not revealed by neutralization of antiviral activity with antibody to IFN-gamma, the presence of IFN-gamma was shown both immunoenzymatically and by detection of specific mRNA in gp120-stimulated cells. The source of IFN-gamma appears to be a T cell present in the CD4-enriched subpopulation. Cultures treated with monoclonal antibodies to the ICAM-1 and LFA-1 adhesion molecules showed an impaired release of both IFN types after gp120 stimulation, suggesting a crucial role of cell-to-cell interactions in the process leading to IFN production. Our data suggest that the HIV envelope glycoprotein could be responsible for the induction of endogenous IFN-alpha and -gamma observed in AIDS patients.

Cell Adhesion Molecules↗
PubMed1993

Potentiation of interferon-alpha in vitro antiviral activity by interferon-gamma is not abrogated by antibody to interferon-gamma.

The addition of minute amounts of recombinant interferon-gamma (IFN-gamma) to recombinant IFN-alpha 2 significantly enhances its antiviral activity. Although this potentiating action of IFN-gamma is destroyed by treatment with acid, it is not significantly affected by treatment with antibodies to IFN-gamma, suggesting that IFN-gamma molecules can interact with cells to potentiate IFN-alpha activity, even in the presence of neutralizing antibodies. Implications of this phenomenon are multifaceted, including the possibility that other IFN activities can be altered synergistically by combinations of different IFN types, even in the presence of specific antibodies, which have been described to occur in vivo in several pathological conditions.

Antibodies↗