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M Sarzotti

Publications and source records attributed to M Sarzotti.

26 records · Page 2Linked to original sources
PubMed1986

Interferon-mediated protection of B16 melanoma cells from cytotoxicity by activated macrophages.

Corynebacterium parvum-activated macrophages (M phi), purified by adherence, were cytotoxic for B16 melanoma cells maintained in vitro. Pretreatment of the melanoma cells for 18 hr with interferon-alpha/beta or -gamma (IFN-alpha/beta or -gamma) caused a reduced susceptibility of the B16 cells to M phi-mediated cytotoxicity. The IFN-induced protective effect of B16 cells from cytotoxic M phi was found to be dose dependent. In addition, IFN-gamma was more protective than IFN-alpha/beta. The protective effect observed with partially purified IFN was reproduced by using highly purified IFN-alpha/beta or recombinant IFN-gamma. Monoclonal antibodies to IFN-gamma neutralized the protective effect provided by IFN-gamma. These results show that the susceptibility of a tumor cell line to killing by activated M phi can be altered by IFN pretreatment.

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PubMed1985

Characterization of cytotoxic cells generated from in vitro cultures of murine bone marrow cells.

Bone marrow cells cultured for 5-6 days generate cytotoxic activity against a number of natural killer (NK)-susceptible tumor cells. In this study, these bone marrow cytotoxic cells were compared to cells with NK activity obtained either from spleen cells activated in vitro with interferon (IFN-alpha/beta) or mitogen or from peritoneal exudate cells (PEC) obtained 4 days after bacillus Calmette-Guerin (BCG) infection. Splenic and PEC cytotoxic cells were shown to be Thy 1.2+, NK 1.1+, Asialo GM+1, Lyt 1.2-, Lyt 2.2-. In contrast, bone marrow cytotoxic cells were Thy 1.2+, NK 1.1-, Lyt 1.2-, Lyt 2.2- and expressed low levels of Asialo GM1 antigen (Asialo GM +/- 1). Precursor cells for bone marrow cytotoxic activity were shown to be Thy 1.2-, NK 1.1-, Lyt 1.2-, Lyt 2.2- but also expressed low levels of Asialo GM1 antigen (Asialo GM +/- 1). Cytotoxic activity for both bone marrow and spleen cells peaked in the low-density fractions of discontinuous Percoll density gradients. The cytotoxic activity of these bone marrow cells was augmented by pretreatment with IFN (-alpha/beta, -gamma) or soluble factors (IFN free) from activated EL-4 thymoma cells. Surprisingly, the ability of bone marrow cells to generate high levels of cytotoxic activity following in vitro culture appeared to be associated primarily with mice which were of the H-2b haplotype.

Animals↗
PubMed1983

Rous sarcoma virus-induced tumours in mice. II. Contribution of H-2 and non-H-2 alloantigen barriers to tumour immunogenicity in vivo.

The features of the immune recognition of a murine fibrosarcoma induced by Rous sarcoma virus were tested in histocompatible and histoincompatible mice. No evidence of a genetic regulation of spontaneous reactivity to tumour-associated antigens was found in various histocompatible F1 hybrids. Incompatibility in multiple minor histocompatibility antigens triggers a host reaction incapable of causing tumour rejection in some cases. The growth rate of incipient tumours is unaffected, whereas that of already visible tumour masses is significantly delayed. Admixture to the challenge of inactivated leukocytes bearing the same minor histocompatibility antigens as the tumour triggers a significantly stronger reaction. The reaction of hosts incompatible in the H-2K or H-2DL regions is quite efficient. However, the intensity of the immune reaction of H-2DLs antigens displayed by tumour cells is markedly dependent on the alleles of genes located in the central regions of the H-2 complex.

Animals↗
PubMed1983

Immune (gamma) interferon production by a murine T cell lymphoma: requirements for macromolecular synthesis and lack of relationship with cell cycle.

Macromolecular synthesis of immune interferon (IFN-gamma) by the L12-R4 T cell lymphoma, stimulated by phorbol myristic acetate, was studied by using reversible inhibitors of protein synthesis, puromycin and cycloheximide, and an irreversible inhibitor of RNA synthesis, actinomycin D. Reversible inhibition of protein synthesis during the first 3 h of stimulation had no effect on IFN-gamma production. The same treatment, performed 4 h after stimulation and maintained for an additional 5 h, decreased significantly the capability of L12-R4 cells to produce IFN-gamma. When the inhibitors of protein synthesis were left in the cultures, a complete block of IFN-gamma production was observed. Irreversible inhibitors of RNA synthesis at the beginning of stimulation did block IFN-gamma production by L12-R4 cells, but the same treatment was ineffective if performed 6 h after stimulation. These data suggest that continued protein synthesis is needed for IFN-gamma production, whereas the RNA seems to be completely synthesized within 4 to 6 h of stimulation. The relationship between IFN-gamma production and cell cycle phases was studied with the aid of a reversible drug, aphidicolin, that arrests cells at the G1/S border. Phorbol myristic acetate stimulation of L12-R4 cells after aphidicolin removal induced comparable levels of IFN-gamma at each different point of stimulation, indicating that IFN-gamma production by stimulated cells is not related to a particular phase but is continuously inducible during the cell cycle.

Animals↗
PubMed1983

Some characteristics of mouse immune (y) interferon produced by a T-lymphoma cell line.

Mouse immune interferon was produced from a T-lymphoma cell line, L12-R4, upon stimulation with phorbol myristic acetate at a concentration of 2 x 10(-7) M/ml. The crude interferon, concentrated by precipitation with (NH4)2SO4 at concentration of 80%, was sequentially chromatographed on two sorbents, namely Sephacryl S-200 and Phenyl-Sepharose CL-4B. With molecular sieve chromatography L12-R4 interferon was observed to have an apparent molecular weight of 45.000 d, while from its chromatographic behaviour on Phenyl-Sepharose CL-4B interferon appeared to be highly hydrophobic like other mammalian interferons. The L12-R4 tumor cells therefore provide a unique source of immune interferon for purification and may represent an useful model for studying the molecular mechanisms involved in T cell differentiation leading to immune interferon production.

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PubMed1982

Interferon production in mixed cultures of murine leukocytes and syngeneic L1210 leukemia cells.

Spleen cells from DBA/2 mice did not proliferate, but released interferon (IFN) when cultured in the presence of mitomycin C-treated syngeneic L1210 leukemia cells apparently free from mycoplasma and common non-oncogenic viral infections. IFN titers reached a plateau after 18 h of culture. The biological activity of this IFN was stable at pH 2 and could be inactivated by antibody raised against alpha and beta-IFN. Removal of phagocytes from the spleen cell suspensions caused a decrease in IFN production. By contrast, suspensions depleted in Thy 1.2-positive cells had an enhanced capacity to produce IFN in response to the L1210 cells.

Animals↗
PubMedDate not supplied

DNA immunization of infants: potential and limitations.

DNA immunization is a relatively new and efficacious approach to vaccination. Only recently have we begun to test the efficacy of DNA vaccines in infants. DNA vaccines for a retrovirus, hepatitis B, influenza, rabies, measles, tetanus toxoid, and sendai virus, have now been proven to induce cellular and humoral immune responses in infant animals. Here we review the field of DNA immunization of newborn animals, some new promising immunization strategies, and the rapid progress obtained in this field.

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