Search PubMed⌕ Search

Biomedical subjects

G Forni

Publications and source records attributed to G Forni.

At least 109 records · Page 6Linked to original sources
PubMed1992

Role of neutrophils and CD4+ T lymphocytes in the primary and memory response to nonimmunogenic murine mammary adenocarcinoma made immunogenic by IL-2 gene.

TS/A is a spontaneous adenocarcinoma, apparently not immunogenic in BALB/cnAnCr mice. TS/A cells are unable to stimulate a syngeneic antitumor response either in vitro or in vivo. To evaluate the immunogenic potential of IL-2-releasing neoplastic cells, we used an expression vector to introduce the cDNA coding for murine IL-2 into TS/A cells. Six clones releasing between 30 and 6800 U of IL-2/10(5) cells/ml/48 h have been isolated. Both low (30 U, B1.30) and high (6000 U, B4.6000) IL-2-releasing clone are capable of stimulating a proliferative and cytotoxic response in syngeneic cultures. While the B1.30 clone grows in 60% of syngeneic mice with a delayed pattern, the five clones that release higher levels of IL-2 are promptly rejected. Rejection is associated with neutrophil infiltration, the intensity of which is directly proportional to the amount of IL-2 released. NK cells and CD4+ lymphocytes are uninfluential, whereas CD8+ lymphocytes play only a minor role. This neutrophil-dominated rejection leaves a long-lasting, tumor-specific, T lymphocyte-mediated immune memory. For its induction, CD4+ lymphocytes are required. Their specific activation appears to depend on both the amount of IL-2 released and the granulocyte-mediated reaction that may lead to a more efficient presentation of tumor-associated Ag. These data support the notion that, after transduction of IL-2 gene, cancer cells may elicit an immune antitumor response, and stress the potential use of IL-2 as a component of new tumor vaccines.

Adenocarcinoma↗
PubMed1992

Growth and spread of human malignant T lymphoblasts in immunosuppressed nude mice: a model for meningeal leukemia.

Previous work has shown that nude (nu/nu) mice additionally immunosuppressed by splenectomy, sublethal irradiation, and treatment with antiasialo GM1 antiserum (SIA-nu/nu mice) have no detectable natural killer activity and allow the growth of human malignant lymphoblasts. We show here that all SIA-nu/nu mice engrafted intravenously with 5 x 10(6) malignant lymphoblasts originally derived from a child with a T-cell acute lymphoblastic leukemia (PF382) and from a boy with a T-cell lymphoma (ST-4) develop lethal meningeal leukemia and die within 35 days. Histologic examination of moribund SIA-nu/nu mice showed that vertebral and skull bone marrow was always replaced by proliferating human T lymphoblasts. From the spinal canal, lymphoblasts spread to the meninges, causing hind leg paralysis. Leaving the skull, they permeated the meninges and then invaded the nervous parenchyma. This efficient and reproducible experimental model may be suitable for experimental studies on the pathogenesis of meningeal leukemia.

Animals↗
PubMed1992

A novel transforming protein (SHC) with an SH2 domain is implicated in mitogenic signal transduction.

A new SH2-containing sequence, SHC, was isolated by screening cDNA libraries with SH2 representative DNA probes. The SHC cDNA is predicted to encode overlapping proteins of 46.8 and 51.7 kd that contain a single C-terminal SH2 domain, and an adjacent glycine/proline-rich motif with regions of homology with the alpha 1 chain of collagen, but no identifiable catalytic domain. Anti-SHC antibodies recognized three proteins of 46, 52, and 66 kd in a wide range of mammalian cell lines. These SHC proteins complexed with and were phosphorylated by activated epidermal growth factor receptor. The physical association of SHC proteins with activated receptors was recreated in vitro by using a bacterially expressed SHC SH2 domain. NIH 3T3 mouse fibroblasts that constitutively overexpressed SHC acquired a transformed phenotype in culture and formed tumors in nude mice. These results suggest that the SHC gene products couple activated growth factor receptors to a signaling pathway that regulates the proliferation of mammalian cells.

3T3 Cells↗
PubMed1992

Distribution of interferon-gamma receptor in human tissues.

Interferon-gamma (IFN-gamma) is produced by activated T lymphocytes and plays a regulatory role in immune responses. The nature and location of cells that express the IFN-gamma receptor (R) and respond to this lymphokine are not well documented. The distribution of human IFN-gamma-R (HuIFN-gamma-R) was, therefore, investigated in situ by immunohistochemistry, using affinity-purified rabbit polyclonal antibodies directed against the extracellular domain of the receptor. In lymphoid organs, IFN-gamma-R expression is restricted to the B cell areas of lymph nodes, adult and fetal spleen, tonsils, appendix, and mucosa-associated lymphoid tissue of the small bowel. Macrophages and other reticular cells in lymphoid tissues and other organs are strongly positive for IFN-gamma-R, whereas its expression was consistently negative in the cortical and medullary thymocytes. Two-color flow cytofluorometric analysis of blood, lymph node, tonsil, spleen and thymus cells confirms that most B lymphocytes are IFN-gamma-R positive, whereas T lymphocytes are negative. However, after in vitro activation, peripheral blood T cells become IFN-gamma-R+. In non-lymphoid organs, IFN-gamma-R is expressed on endothelial cells of the medium- and small-size vessels. In epithelial tissues, high expression of IFN-gamma-R is detected on trophoblastic epithelium, glandular cells of stomach, ileum and colon, lung alveolar cells, salivary duct cells, renal tubular cells, and endometrial mucosa cells. Hepatocytes are weakly positive, while squamous epithelial cells are negative. The distribution of the HuIFN-gamma-R is discussed in view of the known functions of IFN-gamma.

Animals↗
PubMed1992

In vitro and in vivo immunomodulatory activity of ST 789 on two human lymphoblastic T cell lines.

The immunomodulatory activity of the synthetic derivative, N-alpha-5(1,6-dihydro-6-oxo-9-purinyl) pentyloxy-carbonyl-L-arginine (ST 789) has been evaluated by using two human T-cell lines stabilized in our laboratory from the pleural effusion fluid of a patient with acute T lymphoblastic leukemia and from the lymph node biopsy of a child with convoluted T-cell lymphoma, respectively. In vitro, ST 789 did not substantially modify the expression of membrane antigens and the proliferation of both lines, whereas their growth in immunosuppressed nude mice was hampered by the local injection of 0.1 microgram/mouse ST 789 for ten days. The combined administration of ST 789 with human peripheral blood polymorphonuclear cells completely inhibited the in vivo tumorigenicity of the T lymphoma. These in vivo findings show that the antitumor action displayed by ST 789 is probably due to its boosting of natural mechanisms.

Adjuvants, Immunologic↗
PubMed1991

Blockade of physiologically secreted IFN-gamma inhibits human T lymphocyte and natural killer cell activation.

The role of physiologically secreted human IFN-gamma in T lymphocyte and NK cell activation has been probed with a panel of mouse mAb directed against various epitopes of the human IFN-gamma molecule, or human IFN-gamma R. Addition to the culture medium of those mAb that neutralize the antiviral activity of IFN-gamma or interact with its receptor inhibited proliferative and cytotoxic responses elicited in PBL by HLA alloantigens, anti-CD3 mAb, and IL-2, but not the proliferative response to PHA. The IFN-gamma blockade also inhibited IFN-gamma, IL-2, and TNF-alpha release during MLC. Kinetic experiments showed that reduction of proliferative and cytotoxic responses to HLA alloantigens is maximal when IFN-gamma is blocked within the first 48 h. Exogenous rIFN-gamma restored the proliferative response only when added at the beginning. Moreover, when IFN-gamma was blocked, T lymphocytes recovered from 6-day MLC displayed a profound decrease in their expression of p55 and p75 chains of the IL-2R, as well as in the number of high-affinity IL-2 binding sites. These findings strongly suggest that IFN-gamma is required in the early phases of induction of the oligo- and polyclonal proliferative and cytotoxic responses of lymphocytes.

Antibodies, Monoclonal↗
PubMed1991

In vitro and in vivo comparison of the activity of human lymphokine-activated killer (LAK) cells and adherent LAK cells.

The effectiveness of "standard" lymphokine-activated killer (LAK) cells, recovered after 6 days, and of "standard" adherent LAK (A-LAK) cells, recovered after 14 days of culture in the presence of recombinant interleukin-2 (rIL-2) from peripheral blood lymphocytes of 21 healthy donors, was assessed through comparison of their proliferation, surface markers, cytotoxic activity, lymphokine production, and antitumor activity. In the presence of rIL-2, plastic adherent precursors of A-LAK cells proliferated much better than those of "standard LAK" cells and expanded even more than 300-fold. However, the final cell recovery of A-LAK was always lower because of their very few precursors, and the total lytic units (LUs) generated in A-LAK cultures were always lower for the same reason. On the other hand, the lytic activity of each A-LAK cell was always higher than that of a LAK cell. This was particularly evident on day 6 of culture. Removal of nonadherent cells after the first 24 h culture resulted in a significant enrichment in CD3-CD56+ and CD8+CD56+ cells in A-LAK cells, with a marginal number of CD4+ cells. A significant direct correlation between LUs and A-LAK CD3-CD56+ percentage was found. In the presence of rIL-2, A-LAK cells produced higher amounts of tumor necrosis factor-alpha and interferon-gamma than LAK cells, while only A-LAK cells produced IL-1 beta and small amounts of IL-4. Neither LAK nor A-LAK produced IL-2. In the absence of injections of IL-2, LAK and A-LAK cells were equally able to inhibit the growth of a human T-cell lymphoma in immunosuppressed nude mice.

Animals↗
PubMed1991

The effect of preoperative local interleukin-2 (IL-2) injections in patients with head and neck squamous cell carcinoma. An immunological study.

Clinical, immunological, immunophenotypical, pathological and molecular biological studies were performed on tumor infiltrating lymphocytes (TIL) and lymph node lymphocytes (LN-ly) of 8 patients with squamous cell carcinoma of the oral cavity and oropharynx treated with 10 daily locoregional injections of low doses of IL-2 before surgery. No complications were seen during or after surgery. In 3 cases the LN-ly showed a moderate LAK activity, higher in the LN-ly omolateral to the tumor and near the IL-2 injection site; in 2 of these 3 patients a good LAK activity was induced after 6-day culture with IL-2. The LN-ly derived from nodes next to the tumor showed a decreased NK activity and proliferative ability both in basal conditions and after in vitro lymphokine challenging. LN-ly of 2 IL-2 treated patients showed high levels of mRNA encoding for IL-2-R, while it was absent in 2 untreated cases. Immunophenotypical studies on TIL showed statistically improved levels of CD25+ and LAK1+ cells in treated cases. Clusters of CD11c+ (macrophages) cells were seen close to the neoplastic sheets.

Aged↗
PubMed1991

Growth and dissemination of human malignant lymphoblasts in immunosuppressed nu/nu mice.

Athymic nu/nu mice are commonly employed for the heterotransplantation of solid human tumors. Leukemias, however, have consistently proved difficult to transplant and, to enhance their take, recipient nu/nu mice have been variously immunosuppressed. In this study, the natural reactivity against human malignant T lymphoblast (PF382) of splenectomized nu/nu mice (S-nu/nu), nu/nu mice splenectomized and treated with polyinosinic-polycytidylic acid (SIC-nu/nu), and nu/nu mice splenectomized, irradiated and repeatedly injected with antiasialo GM1 antiserum (SIA-nu/nu) has been correlated with the in vivo growth of subcutaneous and intravenous PF382 cell challenges. SIC-nu/nu mice display a marked natural killer (NK) activity, quickly clear 125I-Urd-labelled PF382 cells injected intravenously and do not allow the growth of subcutaneous nor intravenous PF382 cell challenges. S-nu/nu mice display a slightly lower NK activity and slower clearance of 125I-Urd-labelled PF382 cells. Moreover, an intravenous PF382 cell challenge kills 56% of S-nu/nu mice. SIA-nu/nu mice have no NK activity, slowly clear 125I-Urd-labelled PF382 cells and always allow the growth of PF382 cells injected either subcutaneously or intravenously with a consistent pattern. Following the intravenous challenge, PF382 cells first metastasize to liver and kideny, then focal or diffuse infiltrations of the bone marrow and menings become evident. SIA-nu/nu mice thus offer an interesting experimental model for study of the pathogenesis of leukemic infiltration of the meninges, and the exploration of possible therapeutic approaches.

Animals↗
PubMed1990

Low doses of IL-4 injected perilymphatically in tumor-bearing mice inhibit the growth of poorly and apparently nonimmunogenic tumors and induce a tumor-specific immune memory.

The ability of rIL-4 to trigger host reactivity against both a chemically induced fibrosarcoma (CE-2) and a spontaneous adenocarcinoma (TS/A) of BALB/c mice was studied. Daily local s.c. administration around tumor draining lymph nodes of 10 injections of progressive amounts (0.00001 to 1000 pg/day) of rIL-4 induced appreciable inhibition of the growth of both tumors after a dose-response survival curve peaking at 0.1 pg/day. Inasmuch as rIL-4 has no direct antitumor activity, as shown by in vitro tests, host immune reactivity plays a fundamental role in this lymphokine activated tumor inhibition (LATI). LATI, in fact, is abolished when recipient mice are sublethally irradiated or treated with cyclosporin A, or when the reactivity of CD4+ lymphocytes is suppressed, whereas it is not affected by anti-asialo GM1 antibody. The morphologic data show that rIL-4 LATI rests on the recruitment of several cell reaction mechanisms, among which those that are nonspecific seem to predominate. rIL-4 LATI also leads to a state of long lasting and specific immune memory: the growth of a second contralateral tumor challenge is significantly impaired after LATI. This immune memory takes place after LATI of both the poorly immunogenic CE-2 fibrosarcoma and the TS/A adenocarcinoma, previously classed as nonimmunogenic on the basis of immunization-protection tests. In the latter case, adoptive transfer experiments show that Thy-1+ lymphocytes and, in particular, the CD4 cell-depleted T lymphocyte subpopulation, are responsible for the immune memory. Finally, the ability of rIL-4 to trigger LATI is greater than that of the most effective doses of rIL-2, rIL-1 beta, and IFN-gamma, whereas its association with rIL-1 beta induces a more effective immune memory.

Adenocarcinoma↗
PubMed1990

Expression of an exogenous interleukin 6 gene in human Epstein Barr virus B cells confers growth advantage and in vivo tumorigenicity.

The biological role of interleukin 6 (IL-6) molecules in human B cell tumorigenesis was studied by using an episomal expression vector, pHEBoSV-IL6, to introduce stably the human IL-6 gene into human Epstein Barr virus (EBV)-transformed B lymphoblasts. The gene was present in the IL-6-transfected cells in a high copy number and was efficiently expressed, resulting in the secretion of consistent levels of IL-6 molecules. The constitutive expression of the IL-6 gene led to an altered pattern of growth and to a malignant phenotype, as shown by clonogenicity in to an altered pattern of growth and to a malignant phenotype, as shown by clonogenicity in soft agar cultures and tumorigenicity in nude mice. These data suggest that the combined action of EBV, which exerts an immortalizing function, and of the growth-promoting activity of IL-6 molecules, can give rise to fully transformed B cell tumors in immunodeficient subjects.

Animals↗
PubMed1990

Establishment of an EBV-positive lymphoblastoid cell line that grows as a lymphoma in nude mice and expresses membrane CD2 molecules.

We describe a human lymphoblastoid cell line (LCL), called ZS, that originated spontaneously from the cultures of gamma-irradiated (50 Gy) peripheral-blood mononuclear cells of a normal donor. When injected subcutaneously in sublethally irradiated, splenectomized and anti-asialo-GM1-treated nude mice, ZS cells invaded the lymph nodes, that appeared 10 to 50-fold enlarged in all of the mice tested. Furthermore, ZS cells expressed a typical T-cell surface structure, the CD2 molecule, detectable by a variety of different anti-CD2 monoclonal antibodies (MAbs). However, other T-cell markers were not found, with the possible exception of a truncated messenger of the beta chain of the T-cell receptor and ZS cells could be identified as B cells since they (i) expressed a battery of markers of the resting and activated B cells, (ii) displayed a monoclonal rearrangement of the IgH chain locus and (iii) synthesized IgM K molecules. The Epstein-Barr virus (EBV) genome was detected in ZS cells in approximately ten copies per cell by DNA hybridization techniques. Furthermore, the cells were positive for EBV nuclear antigens (EBNA). Western blotting analysis of EBV encoded antigens demonstrated clear differences with those present in the B 95.8 virus-producer cell line, indicating that ZS cells were not infected by EBV in vitro and that they already harbored the virus in vivo. ZS cells formed colonies in vitro with a high cloning efficiency and displayed chromosomal abnormalities in all of the mitoses (karyotype 47, xy, +13, -14, 8p+, 21p+, +m). In spite of these malignant features, ZS cells expressed the full range of EBV latent proteins as usually do "normal" LCSs and did not have any of the chromosomal abnormalities that juxtapose the c-myc oncogene to one of the genes coding for immunoglobulin molecules.

Animals↗
PubMed1990

Interleukin 2 does not promote the in vitro and in vivo proliferation and growth of human acute leukaemia cells of myeloid and lymphoid origin.

The effect of recombinant interleukin 2 (IL2) on the in vitro and in vivo proliferation and growth of human acute leukaemia cells of both myeloid and lymphoid origin was investigated. In none of the 25 primary samples tested could a continuously in vitro growing cell line be obtained by adding IL2 to the culture medium. Although IL2 induced a proliferative signal in three of the 31 acute leukaemias analysed, the overall 3H-thymidine uptake of the neoplastic cells was significantly reduced (P less than 0.05) in the presence of IL2. The unlikelihood of an important proliferative signal triggered by IL2 was confirmed in a semisolid clonogenic assay, which failed to document an increased colony growth in the 26 samples studied. Furthermore, using a colorimetric assay as a test for cell proliferation and survival, in seven of the 11 fresh acute leukaemia samples tested a 22-40% reduction in viability was observed in the presence of IL2, while in the remaining four, IL2 was ineffective. In order to investigate the effect of IL2 in an in vivo setting, an experimental model in heavily immunosuppressed nu/nu mice was established. In no case did IL2 promote the in vivo proliferation and growth of human myeloid and lymphoid acute leukaemia cells injected in the mice. On the contrary, with seven of the eight leukaemic cell lines which gave rise spontaneously to leukaemic masses, this could be prevented when the mice received locally 300 U of IL2 three times daily for 90 d. IL2 also blocked the growth in vivo of three fresh acute leukaemia samples (two myeloid and one lymphoid). Co-culture experiments using leukaemic cell lines and increasing numbers of normal lymphocytes suggest that the inhibitory effect of IL2 is probably exerted via an indirect mechanism. These findings, coupled to the well-documented ability of IL2 to generate lymphokine activated killer cells cytolytic against leukaemic blasts, further point to the potential role of immunotherapy with IL2 in the management of patients with haematological malignancies.

Animals↗
PubMed1990

Perilymphatic injections of cytokines: a new tool in active cancer immunotherapy. Experimental rationale and clinical findings.

Various strategies for local immunotherapy performed by using lymphokines and lymphocytes are presented. In experimental mice models, the antitumor reaction elicited through the injection of little amounts of IL-2 and gamma-IFN at the tumor growth site is significantly enhanced by the concurrence of lymphocytes from tumor bearing mice artificially admixed to challenging tumor cells. These lymphocytes act as initiator or helper cells that elicit both a local and a systemic long lasting immune reaction by the release of additional lymphokines. The reaction activated mostly involves draining lymph nodes, where multiple reaction mechanisms are induced. The local injection of cocktails of molecularly defined lymphokines can also mimic the helper action of lymphocytes and trigger a similarly effective anti-tumor reaction. A set of pilot clinical trials with IL-2 or gamma-IFN injected perilymphatically were initiated in patients with advanced primary or recurrent localized tumors of the head and neck and the bladder. This treatment appears to elicit a local reaction by activating a few pathways of patients immunoreactivity, whose efficiency may well be high, as shown by the tumor inhibition often observed.

Amino Acid Sequence↗
PubMed1990

Assessment of the potential malignancy of Epstein-Barr virus (EBV)-infected B cells in AIDS-related disorders.

Spontaneous lymphoblastoid cell lines (LCLs) were established from the peripheral blood of ten human immunodeficiency virus (HIV)-seropositive patients in order to investigate whether or not a progression of the cells toward a malignant state could be traced. The LCLs studied displayed no differences in their surface phenotype, karyotype, or tumorigenicity in nude mice when compared with a wide panel of control LCLs. However, four of the ten LCLs derived from HIV-seropositive patients formed colonies in agar with a cloning efficiency (0.1 to 0.9%) that was much lower than that of a control neoplastic B cell line (50%). Some sublines that were derived form the agar colonies expressed new activation markers (CD10 and Bac-1) but did not produce tumors in nude mice or display chromosomal abnormalities. These sublines might comprise cells that have progressed toward a more transformed state.

Animals↗