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Biomedical subjects

C Mongini

Publications and source records attributed to C Mongini.

7 recordsLinked to original sources
PubMed1996

Enhancement of anti-tumour immunity in syngeneic mice after MHC class II gene transfection.

The relationship between tumorigenicity and expression of MHC class II molecules in a class II-negative murine leukaemia cell line (LBC) was studied. Analysis of structural DNA sequences encoding MHC class II proteins was performed by Southern blot with DNA isolated from both the original LB tumour and LBC cell line, digested with EcoRI, BamHI and HindIII and hybridised with specific probes for I-A alpha d and I-A beta d chains. Similar patterns were obtained for LB, LBC and normal BALB/c lymphocytes. In vitro treatment with IFN-gamma (20 - 1000 IU ml-1) failed to induce the expression of MHC class II antigens in LBC cell line. LBC cells were tri-transfected by a liposome-mediated protocol with I-A alpha d, I-A beta d genes and pSV2neo. Cells were selected for growth in medium containing Geneticin (G418). Surviving transfectants were cloned and three I-A+ clones were obtained after 20 days (LBCT cells). Syngeneic mice inoculated with 1.0 x 10(3) LBCT (I-A+) cells failed to develop a tumour, whereas the DT50 of mice injected with 1.0 x 10(6) LBCT cells was three times the value for mice injected with LBC cells (I-A-). Furthermore, specific CTL response against tumour cells was significantly enhanced upon priming with irradiated LBC-transfected cells (27 +/- 2%) compared with irradiated LBC cells (15 +/- 1.5%) in a 4 h 51Cr-release assay. It is suggested that neoexpression of MHC class II molecules enhances anti-tumour response by transforming tumour cells into professional antigen-presenting cells (APCs), which may be used to improve tumour-specific immunity in the autologous host.

Animals↗
PubMed1995

Induction of anti-tumour immunity in syngeneic mice by a leukaemic cell line.

Induction of anti-tumour immunity in syngeneic mice by LBC cell line derived from a non-immunogenic T cell leukaemia was studied. The immunization of BALB/c mice with LBC irradiated cells induced in them anti-tumour spleen cells, cytotoxic T lymphocytes and anti-LBC antibodies. The anti-LBC antibodies reacted with components of 14, 16 and 27 kDa present on LB tumour cells, LBC cell line and normal thymocytes, but not with normal lymph node cells. Furthermore, immunization of the autologous hosts with LBC cells partially protected them against subsequent challenge with the original LB leukaemic cells. These findings demonstrate that culture conditions induced modifications in the antigenic properties of the leukaemic cells, allowing LBC cells to stimulate an immune response directed against components expressed at early stages during T cell maturation. These results also suggest that the immune response is responsible for the prolongation of the survival time of the mice inoculated with the parental leukaemic cells.

Animals↗
PubMed1994

Inhibitory activity of soluble IL-2R in sera, ascites and culture supernatants from murine leukaemic cells.

The effect of sera from mice bearing a T cell lymphoid leukaemia (LB) and the supernatants from short term cultures of the tumour cells were studied on cell proliferation using syngeneic and allogeneic normal and tumour cells. An inhibitory activity was demonstrated in 24-48 h supernatants of LB cells in culture and disappeared after 4 days of culture. Inhibitory activity was cytostatic but not cytotoxic and was non-specific since it inhibited the growth of both syngeneic and allogeneic normal and tumour cells. Such activity was found in the 10(5)-1.3 x 10(5) M(r) serum fraction after a Sephacryl S200 chromatography. Though sensitive to protease, trypsin or neuraminidase treatment, which indicated its glycoprotein nature, it remained stable after heating or freezing-thawing cycles as well as after alkaline, acid or hyaluronidase treatment. Addition of exogenous IL-2 abrogated inhibitory activity. ELISA showed the presence of soluble IL-2R both in LB conditioned medium and in above serum fraction. It is demonstrated that the inhibitory factor, soluble IL-2R, is produced by LB leukaemia cells, then secreted into blood and ascitic fluid or released into culture supernatants. Soluble IL-2R exerts inhibitory activity blocking cell proliferation and modulating immune response by binding to free IL-2.

Animals↗
PubMed1990

Comparative study of cell-immunoenzymatic methods for the estimation of IgG and IgM anti-Brucella antibodies in the diagnosis of human brucellosis.

Two methods which employ whole cells are described and compared for the detection of human IgG and IgM anti-brucella antibodies. Dot ELISA and ELISA were shown to be suitable for a screening diagnosis of human brucellosis. Titres of antibodies obtained by dot ELISA showed 100% coincidence for IgG and 97% for IgM, compared with agglutination and complement fixation tests; when ELISA was used 11% positive sera were not detected. The comparison of these two methods with the conventional serological test kit indicated that both dot ELISA and ELISA were sensitive, reproducible and specific for the quantification of IgG and IgM antibrucella antibodies.

Agglutination Tests↗
PubMed1989

[Surface markers and humoral factors in spontaneous murine leukemia].

This paper presents a model of spontaneous BALB/c lymphoma (LB) useful for the study of the relationship between the tumor and the immune system. Characterization of this tumor was done by FACS and it was determined that the tumor cells are T lymphocytes which express both CD4 and CD8 membrane markers but not the viral protein gp 70. In addition, tumor cells express IL-2 receptors and class I, but not class II, H-2 antigens. Antibodies were not detected in sera or ascitic fluid of syngeneic mice bearing a tumor transplant while both sera and ascites contained a suppressor factor that inhibited in vitro the proliferation of tumor cells and blastogenesis of normal BALB/c splenocytes after Concanavalin A stimulation. The results indicate that this tumor may be used as an experimental model for adult T cell leukemia as well as for the isolation and characterization of cytokines which may be responsible for the immunological unresponsiveness found in certain cancer patients.

Animals↗