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Biomedical subjects

C Garzelli

Publications and source records attributed to C Garzelli.

At least 19 recordsLinked to original sources
PubMed1992

Epstein-Barr virus-transformed B lymphocytes produce low molecular mass molecules with autocrine growth factor and competence factor activity.

A human Epstein-Barr virus (EBV)-positive lymphoblastoid B cell line, named BA-D10-4, produces a factor of a molecular mass less than 10 kDa that promotes cell proliferation of both BA-D10-4 cells and other human T or B lymphoid cell lines, either EBV-positive or -negative. The factor synergizes with higher molecular mass autocrine growth factors and makes both BA-D10-4 cells and B cell lines from Burkitt's lymphoma, but not cells from T cell leukemia, more responsive to interleukin-1 and interleukin-6. Therefore, this low molecular mass factor seems to be an autocrine growth factor per se and to have the characteristics of a competence factor.

B-Lymphocytes↗
PubMed1992

Antibodies to histones in infectious mononucleosis.

A polyspecific human monoclonal (auto)antibody, isolated from a patient in the acute phase of infectious mononucleosis, was found to react with all subfractions (H1, H2A, H2B, H3 and H4) of histones. This finding prompted us to study the occurrence of antibodies to histones in sera of patients with infectious mononucleosis. It was found that IgM binding to histones was detectable both in control and patient sera; however, sera from patients showed binding values of IgM antibodies to histones significantly higher than those of healthy controls; moreover, both in control and patient groups anti-histone IgM activity was found to correlate with serum IgM concentration. These findings suggest that anti-histone IgM antibodies belong to the class of antibodies defined as "natural antibodies" and that their increase during infectious mononucleosis is due to Epstein-Barr virus-induced polyclonal B cell activation.

Antibodies, Monoclonal↗
PubMed1992

Detection of an idiotope on a human monoclonal autoantibody by monoclonal anti-idiotypic antibody and its relationship to Epstein-Barr virus-induced autoimmunity.

We have recently described a human IgM monoclonal antibody (mAb), reactive with both self antigens, i.e., cytoskeleton filaments and smooth muscle, and Epstein-Barr virus (EBV)-induced nuclear antigen (EBNA), produced by EBV-transformed B lymphocytes isolated from a patient with infectious mononucleosis (IM). In order to achieve higher antibody secretion in culture supernatant, the mAb-producer cells were fused with ouabain-resistant mouse myeloma cells and a stable human-mouse heterohybrid, coded HY 5488, producing up to 80 micrograms/ml IgM mAb, was isolated after 4 cloning procedures. Purified HY 5844 mAb was used to immunize mice for the production of a murine anti-idiotypic mAb, which was used to probe the expression of the idiotope of HY 5488 mAb (Id 5488) in sera of IM patients and normal controls by ELISA. It was found that Id 5488 is expressed both in IM patients and normal controls, and that Id 5488 expression is significantly higher in IM patients' sera; furthermore, in IM sera a statistically significant correlation between Id 5488 expression and anti-cytoskeleton and anti-smooth muscle autoantibodies was found. It is suggested that at least part of EBV-induced IgM autoantibodies appearing during IM are secreted by B lymphocytes programmed to the production of "natural antibodies" bearing Id 5488-like idiotopes.

Animals↗
PubMed1992

Density-dependent responsiveness to autocrine growth factors of Epstein-Barr virus transformed human B lymphocytes.

Analysis of the growth requirements of Epstein-Barr virus (EBV)-transformed B lymphocytes shows that interleukin 1 and thioredoxin, a disulfide reducing enzyme, are able to induce a marked increase in DNA synthesis in the early phases of in vitro culture. By contrast, interleukin 6 induces a steady increase in DNA synthesis comparable to that observed with crude conditioned supernatant. Furthermore, EBV-transformed B cells exhibit a density-dependent responsiveness to autocrine growth factors, thus suggesting that growth regulation of EBV-transformed B cells might result from the interplay between different self-stimulating soluble factors and from the competence of the cells to respond to autocrine growth factors.

B-Lymphocytes↗
PubMed1991

Activity of soluble factors produced by Epstein-Barr virus-transformed human B lymphocytes on different cell lines.

Self-stimulatory growth factors, produced by a human Epstein-Barr virus (EBV)-positive lymphoblastoid B cell line, named BA-D10-4, have been tested for the capacity to induce DNA synthesis in various human and animal cell lines, including lymphoid, either EBV-positive or EBV-negative, and non-lymphoid cell lines. It has been found that BA-D10-4 cells produce growth factors which seem to be essential for their sustained proliferation in vitro, and which increase DNA synthesis in different primate lymphoid cells, independently of the presence of the EBV genome and of the lymphocyte lineage.

B-Lymphocytes↗
PubMed1991

Identification of a novel nuclear protein synthesized in growth-arrested human hepatoblastoma HepG2 cells.

DNA synthesis of human hepatoblastoma HepG2 cells is reversibly inhibited by butyrate. When butyrate is removed from the culture medium, cells re-enter the cell cycle, synthesizing DNA with a time lag of about 12 h. HepG2 cells, growth-inhibited for 30 h with butyrate, synthesize and accumulate a nuclear protein, called D. Protein D synthesis is inhibited in cells which, released from the butyrate block, have resumed DNA synthesis as well as in growing cells never exposed to butyrate. Protein D has been purified from growth-arrested cells and partially sequenced. The amino acid sequences of five internal trypsin peptides indicate that protein D is a novel nuclear protein.

Amino Acid Sequence↗
PubMed1991

Activation of murine autoreactive b cells by interleukin 1-like factors released from synovial inflammatory cells of rheumatoid arthritis patients.

The effect of interleukin 1 (IL-1)-like factor(s), produced by cells isolated from the synovial fluids of rheumatoid arthritis (RA) patients, on an in vitro murine model of spontaneous autoimmunity, i.e., the development of plaque-forming cells (PFC) to bromelain-treated mouse red blood cells (Br-MRBC) in mouse peritoneal cell (PC) cultures, has been investigated. It has been found that IL-1-containing culture supernatants from cells isolated from joint fluids of RA patients, as well as recombinant IL-1, determine a marked increase in anti-Br-MRBC PFC development. Moreover, factor(s) of 10-20 KD molecular weight, with IL-1-like biological activity, capable of increasing the anti-Br-MRBC PFC development in mouse PC cultures, have been demonstrated in joint fluids from RA patients. The finding that synovial inflammatory cells produce factors that activate autoreactive B cells further supports the role of autoimmunity in the pathogenesis of rheumatoid arthritis, as self-perpetuing disorder.

Animals↗
PubMed1990

Fr-MLV infection induces erythroleukaemia instead of lymphoid leukaemia in mice given pituitary grafts.

Here we report that the slow-transforming helper component of Friend murine leukaemia virus (Fr-MLV), which produces lymphoid leukaemias in normal mice, induces erythroleukaemia in mice given syngeneic pituitary grafts (SPG). Newborn mice were infected with Fr-MLV and, at one month of age, were transplanted with two pituitary glands under the kidney capsule. Sham-operated infected mice and uninfected transplanted mice served as controls. SPG selectively reduced the mean survival times of infected mice. Histopathology showed that, while most infected non-transplanted mice developed lymphoid leukaemias, virtually all Fr-MLF-infected mice given SPG developed erythroleukaemias. Experiments in vitro showed that Fr-MLV infection markedly depressed concanavalin A induced DNA synthesis in cells from spleen, thymus and lymph nodes. Addition of prolactin or growth hormone further suppressed lectin-induced mitogenesis of lymphoid cells from infected mice, but failed to influence the response of uninfected controls. These experiments indicate that, in mice, pituitary hormones modulate the development and the histological features of Fr-MLV induced leukaemias, and suggest that endocrine-immunological interactions play a role in retrovirus induced tumorigenesis.

Animals↗
PubMed1989

A simple method for the biochemical purification of Ro/SS-A antigen.

In the present study, Ro/SS-A antigen has been isolated from human spleen by a two-step procedure. In the first step most of the non-antigenic material was removed by means of ammonium sulphate precipitation and ion exchange chromatography. The final purification was obtained by passing the Ro/SS-A-containing fractions twice through a Mono Q ion exchange fast protein liquid chromatography (FPLC) column. The purified antigen showed identical immunoreactivity with crude material on CIE and was composed of two polypeptides with a molecular weight of approximately 60,000 and 55,000 respectively on SDS-PAGE, both reacting on Western blotting with a panel of anti-Ro/SS-A antisera. This system permits milligrams of highly purified antigen to be obtained from grams of human spleen.

Autoantigens↗
PubMed1989

A human monoclonal autoantibody isolated from a patient with infectious mononucleosis reactive with both self antigens and Epstein-Barr virus nuclear antigen (EBNA).

In order to investigate the mechanism(s) by which Epstein-Barr virus (EBV) induces the outcome of autoantibodies during infectious mononucleosis (IM), a human IgM (k) monoclonal antibody to cytoskeletal filaments of epithelial cells has been prepared by EBV transformation of peripheral blood B lymphocytes obtained from a patient with IM. The antibody was also found to react with smooth muscle of frozen sections of human stomach tissue by immunofluorescence, and with the Epstein-Barr nuclear antigen (EBNA) by an enzyme-linked immunosorbent assay. These findings demonstrate at the clonal level the epitope homology between host's cell antigens and EBV-encoded nuclear antigen, which might have relevance in EBV-induced autoimmunity.

Antibodies, Monoclonal↗
PubMed1989

Epstein-Barr virus-transformed human B lymphocytes endocytose autologous and heterologous red blood cells.

Epstein-Barr virus (EBV)-transformed B lymphocytes, either isolated from a patient with EBV-induced infectious mononucleosis or obtained by in vitro infection of B lymphocytes of donors in different clinical conditions, have been tested for the ability to endocytose particulate forms of antigens, such as human, sheep or mouse red blood cells. By light and electron microscopy, it has been found that EBV-transformed B cells are able to bind and internalize human autologous and allogeneic erythrocytes, as well as sheep and mouse erythrocytes, independent of the specificity of the secreted immunoglobulins. The ability of EBV-transformed B lymphocytes to endocytose and process particulate forms of autoantigens during infectious mononucleosis might have a role both in the production of heterophile antibodies and in EBV-induced autoimmunity.

Animals↗
PubMed1989

Mechanisms other than polyclonal B cell activation possibly involved in Epstein-Barr virus-induced autoimmunity.

In order to verify whether Epstein-Barr virus (EBV)-induced polyclonal B cell activation is the major cause of autoimmunity during infectious mononucleosis (IM), we have investigated, by immunoblotting, the fine specificity of anti-smooth muscle autoantibodies (autoAbs) in the sera of IM patients. Furthermore, we have isolated a number of in vivo infected EBV-positive cell lines from a patient with IM and compared the reactivity of the secreted immunoglobulins (Igs) with that of serum autoAbs. The reactivity of anti-smooth muscle autoAbs was found to be closely restricted to three proteins of approximate molecular weights 54, 52 and 48 kD. Furthermore, none of 48 EBV-positive B cell lines shared any reactivity with serum autoantibodies. Taken together, these results suggest that EBV-induced autoimmunity is not a consequence of a random activation of B cells, but a specific phenomenon, requiring mechanisms other than polyclonal B cell activation.

Antibody Specificity↗
PubMed1988

Interleukin-1-like activity produced by hybrids constructed with Epstein-Barr-virus-transformed human B lymphocytes and mouse myeloma cells.

Peripheral blood B lymphocytes from a donor with positive tuberculin skin test reaction were transformed into lymphoblastoid cell lines by Epstein-Barr virus and then fused by polyethylene glycol with mouse myeloma cells. Human-mouse hybrid cells producing human IgM monoclonal antibody to purified protein derivative of tuberculin were isolated, and the concentrated supernatant of one of these cell hybrids was tested for the capacity of interfering with DNA synthesis of human and mouse lymphocytes. The hybrid cell supernatant was found to contain soluble factors that increased DNA synthesis in unstimulated human and mouse lymphocytes and that, conversely, decreased DNA synthesis in concanavalin-A-stimulated cells. Gel filtration experiments showed that these antagonistic activities were due to at least two different factors, one of which resembled human interleukin-1 in biochemical and biological properties.

Animals↗
PubMed1988

Virus-induced thyroiditis.

Mice infected with reovirus type 1 developed a mild thyroiditis characterized by focal destruction of acinar tissue, infiltration of inflammatory cells, and autoantibodies to thyroglobulin and microsomal antigens. Thyroid involvement appears to be part of a more generalized virus-induced polyendocrine disease.

Animals↗
PubMed1987

Multiple organ-reactivity of monoclonal autoantibodies to mouse erythrocytes.

Autoantibodies reacting with bromelain-treated autologous mouse red blood cells (Br-MRBC) are spontaneously produced by normal mice. In order to understand the biological significance of these autoantibodies, anti-Br-MRBC monoclonal autoantibodies have been prepared and studied for reactivity with a panel of frozen tissue sections from organs of normal mice by direct immunofluorescence. It has been found that the anti-Br-MRBC monoclonal autoantibodies are polyspecific, since they react with cells in multiple organs.

Animals↗
PubMed1987

Epstein-Barr virus-transformed B cells process and present Mycobacterium tuberculosis particulate antigens to T-cell clones.

We have analyzed the presentation of mycobacterial antigens by Epstein-Barr virus-transformed human B (EBV-B) cells to mycobacteria-specific T-cell clones and lines, and to purified resting T cells. EBV-B cells were able to process and present not only soluble forms of antigen, such as PPD and the expressate preparation of M. tuberculosis strain H37Rv, but also particulate forms of antigen, such as whole mycobacterial H37Rv or M. bovis organisms. Electron microscopy studies demonstrated the capacity of EBV-B cells to phagocytose mycobacterial cells in 18 hr and pulsing experiments confirmed that an 18-hr of incubation is required for an efficient processing and presentation of mycobacterial determinants to T cells. The processing of whole-H37Rv particulate antigen by EBV-B cells was inhibited by the lysosomotrophic compound chloroquine and by high doses of irradiation. Finally, the analysis of the presentation of soluble and particulate mycobacterial antigens by PPD-positive and PPD-negative EBV-B cell clones has shown a preferential presentation of both forms of antigen by PPD-positive EBV-B clones.

Antigen-Presenting Cells↗
PubMed1986

Human monoclonal antibody to purified protein derivative of tuberculin produced by hybrids constructed with Epstein-Barr virus-transformed B lymphocytes and mouse myeloma cells.

A method of producing human monoclonal antibody by combining somatic cell hybridization technology with the capability of Epstein-Barr virus (EBV) to transform human B lymphocytes is described. Peripheral blood lymphocytes from a donor with positive tuberculin skin test reaction were transformed by EBV and then tested for antibody production to mycobacterial purified protein derivative (PPD) by an enzyme-linked immunosorbent assay. Two EBV-transformed lymphoblastoid cell lines making IgM antibodies to PPD were obtained. One of these cell lines was fused by polyethylene glycol with a murine hypoxanthine-guanine phosphoribosyl transferase-deficient myeloma cell line that had been selected for resistance to ouabain. The human-mouse hybrids were selected in ouabain-containing HAT medium and 11 heterohybridomas producing IgM antibody to PPD were obtained. One of these was cloned by limiting dilution with efficiency at least 20-fold higher than parent EBV-transformed cell line. Heterohybridoma subclones reached levels of IgM antibody as high as 75.0 micrograms/ml of culture medium, whereas IgM production of EBV-transformed B cell clones ranged between 3.0 and 4.0 micrograms/ml.

Animals↗