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Biomedical subjects

L Romani

Publications and source records attributed to L Romani.

At least 127 records · Page 7Linked to original sources
PubMed1983

Systemic adoptive immunotherapy of a highly immunogenic murine lymphoma growing in the brain.

Systemic adoptive immunotherapy with specifically immune lymphocytes was successfully performed in immunodepressed mice challenged intracerebrally with L5178Y/DTIC lymphoma cells, a tumor subline rendered highly immunogenic through in vivo exposure to 5-(3,3-dimethyl-1-triazenyl)-IH-imidazole-4-carboxamide (DTIC). The systemic immunotherapy relied on the infusion of the in vitro-generated primary cytotoxic T-lymphocytes (CTL), the anti-tumor activity of which was evaluated by measuring tumor-cell proliferation in the brain in terms of radiolabel uptake and by recording survival times of recipient leukemic mice. The protection afforded by CTL appeared to be specific and was largely conditioned by dose and time of CTL administration. The levels of protection correlated well with the in vitro killing of L5178Y/DTIC tumor cells.

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PubMed1983

Susceptibility of murine lymphoma cells treated with 5-(3,3-dimethyl-1-triazenyl)-1H-imidazole-4-carboxamide to NK-mediated cytotoxicity in vitro.

Novel drug-mediated tumor antigens (DMTA) have been detected in chemically induced L5178Y lymphoma of DBA/2 origin, following treatment of tumor-bearing hosts with 5-(3,3-dimethyl-1-triazenyl)-1H-imidazole-4-carboxamide (DTIC). Studies were conducted on the susceptibility of the DTIC-treated subline, maintained in tissue culture, to NK-mediated cytolysis in vitro. The results of the experiments showed that DTIC-treated lymphoma cells are less susceptible to NK cell lysis than the parental line (i.e. L5178Y); the DTIC-treated lymphoma, maintained in vivo as ascitic form, behaved as the corresponding in vitro line, thus suggesting that NK-resistant phenotype was not dependent upon propagation conditions. The intrinsic susceptibility to cell-mediated lysis of the DTIC-treated tumor was unchanged, as demonstrated by lysis produced by alloimmune cytotoxic cells or by natural cytotoxic mesenteric lymph node effectors. "Cold" competition experiments and target binding assay performed with L5178Y/tc and its DTIC-treated subline showed that DTIC-altered cells are less efficient than the parental line as "cold" competitor cells for NK-mediated lysis and bind less efficiently than L5178Y tumor to NK lymphocytes. These data suggested that the NK resistance of the DTIC-treated lymphoma may result from a failure to bind to effector cells, as a consequence of a profound rearrangement of the cell surface produced by DTIC treatment of cancer cells.

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PubMed1983

Drug-induced immunogenic changes of murine leukemia cells: dissociation of onset of resistance and emergence of novel immunogenicity.

n vivo exposure of tumor-bearing mice to the antineoplastic agent 5-(3,3-dimethyl-1-triazenyl)-1H-imidazole-4-carboxamide (DTIC) results in increased immunogenicity of tumor cells, an event often referred to as "chemical xenogenization" (CX). To verify the hypothesis of DTIC-induced somatic mutation(s) as the major mechanism underlying CX, studies were performed to dissociate CX from the onset of drug resistance, which was invoked in the past as an event leading to selection of preexisting immunogenic clones. Therefore, experiments were done with a DTIC-susceptible tumor line treated with DTIC and quinacrine dihydrochloride (Q), an antimutagenic compound, according to selected experimental schedules. At different transplant generations, the CX and the onset of drug resistance were evaluated. The results show that a) Q does not prevent the onset of DTIC resistance, b) DTIC-resistant clones arising after treatment with DTIC plus Q are not immunogenic, and c) CX is selectively antagonized by Q. The present data confirm that DTIC-induced immunogenicity is not the result of a selection mechanism mediated by the drug and give further support to the hypothesis that the molecular mechanism of CX may be related to somatic mutation(s).

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PubMed1982

Intracerebral adoptive immunotherapy of a murine lymphoma antigenically altered by drug treatment in vivo.

Intracerebral tumor neutralization assay and adoptive immunotherapy with in vivo sensitized lymphocytes were done in immunodepressed mice challenged intracerebrally with L5178Y/DTIC lymphoma, a tumor subline antigenically altered by treatment with 5-(3,3-dimethyl-1-triazenyl)-1H-imidazole-4-carboxamide (DTIC) in vivo. Primary cytotoxic T-lymphocytes (CTL) were generated in vitro against L5178Y/DTIC cells with the use of splenocytes of histocompatible (BALB/cCr X DBA/2Cr)F1 donors. The extent of antitumor activity of CTL was evaluated by the measurement of tumor cell proliferation in the brain, as judged by the 125I-labeled 2'-deoxyuridine uptake values and by survival times of recipient mice. The results of the experiments showed: a) CTL were highly effective in inhibiting tumor growth when they were injected along with L5178Y/DTIC tumor cells in a Winn-type neutralization assay; b) the tumor inhibition mediated by CTL was specific, since no antilymphoma effects were detected when CTL sensitized against L5178Y/DTIC line were admixed with the parental L5178Y tumor or with other unrelated lymphoma cells; and c) local adoptive immunotherapy with CTL given on day 1, 3, or 5 after the intracerebral challenge with L5178Y/DTIC lymphoma substantially impaired tumor cell proliferation and significantly increased survival times of recipient leukemic mice.

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PubMed1980

Appearance of strong transplantation antigens in non-immunogenic lymphoma following drug-treatment in vivo.

A chemically induced lymphosarcoma line (LSBM-1) of C57BL/10 (H-2b) origin lacks detectable TATA and is scarcely immunogenic for H-2-incompatible congenic recipients. New antigenic specificities, defined as drug-mediated tumor antigen(s) (DMTA) were found in a subline (LBD-1) obtained by in vivo treatment of LSBM-1 with the anti-neoplastic agent dimethyl-1-triazeno-imidazole-carboxamide (DTIC) over several transplant generations. It was concluded that the presence of detectable TATA is not a prerequisite for the induction of new antigenic specificities (DMTA).

Animals↗
PubMed1979

[Transfer in vivo of cytotoxic immune lymphocytes obtained in vitro in primary culture against a murine lymphoma antigenically altered by DTIC].

Specific cytotoxic T cells were obtained by coculturing "in vitro" normal spleen cells with inactivated histocompatible DTIC-altered lymphoma cells. The "in vivo" antitumor activity of such sensitized lymphocytes was evaluated by injecting a mixture of lymphocytes + tumor into the brains of lethally irradiated syngenic mice. The results indicated that such lymphocytes demonstrate antitumor activity against the same tumor but not against unrelated tumors.

Animals↗
PubMed1979

[Experimental models of immunochemotherapeutic synergism: study of the influence of the treatment schedule].

Graded doses of LSTPA or L1210 leukemia cells were injected ip or iv into fully compatible hosts or mice incompatible for Multiple Minor Histocompatibility Loci (MMHL). Three days later the animals were treated with single doses of BCNU, NM, DTIC and VCR. The results showed that NM and VCR could synergize with the weak anti-tumor immune responses of MMHL-histocompatible mice only upon ip injection of the tumor. If the same tumor has been injected iv, only BCNU could synergize with the host's antitumor response. On DTIC treatment, no synergistic effects were detectable for either route of tumor's challenge.

Animals↗
PubMed1979

In vitro generation of primary cytotoxic lymphocytes against L5178Y leukemia antigenically altered by 5-(3,3'-dimethyl-1-triazeno)-imidazole-4-carboxamide in vivo.

Drug-mediated tumor antigens (DMTA), which appear after in vivo treatment of murine lymphomas with 5-(3,3'-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC), are shown to elicit strong primary cell-mediated responses in vitro. Specific cytotoxic response is obtained using CD2F1 (H-2d/H-2d) spleen cells cocultured in vitro for 5 days with inactivated histocompatible L5178Y/DTIC lymphoma cells in a one-way mixed lymphocyte tumor culture. Sensitized lymphoid cells are markedly cytotoxic for L5178Y/DTIC targets and are minimally or not active against the parental lymphoma. Marginal or no cross-reactivity is found between L5178Y/DTIC lymphoma and other untreated or DTIC-treated tumor or normal cells. Cytotoxic activity is T dependent, since it is abrogated by treatment in vitro with anti-serum and complement and is not elicited by spleen cells of athymic (nude) donors.

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