Biomedical subjects

Guido Forni

Publications and source records attributed to Guido Forni.

51 records · Page 3Linked to original sources

PubMed2003

Myeloid cell expansion elicited by the progression of spontaneous mammary carcinomas in c-erbB-2 transgenic BALB/c mice suppresses immune reactivity.

Transgenic female mice expressing the transforming rat oncogene c-erbB-2 (HER-2/neu) under the mouse mammary tumor virus (MMTV) promoter (BALB-neuT) spontaneously develop mammary carcinomas with a progression resembling that of human breast cancer. In these mice, activating antitumor immunotherapy fails to induce T cell-mediated cytotoxicity, suggesting a suppression of the immune response. We found a direct correlation between tumor multiplicity and an increased proportion of Gr-1+ (Ly6G)/Mac-1+(CD11b)/ER-MP12+(CD31) immature myeloid cells in the peripheral blood (PB) and spleen, suggesting that tumor load profoundly affects overall BALB-neuT hematopoiesis. In fact, myeloid colony formation was increased in bone marrow (BM) and spleen. The immature myeloid cells displayed suppressive activity on host T lymphocytes, which progressively failed to respond to alloantigens and CD3 triggering, while maintaining the ability to proliferate in response to nonspecific mitogens. Transplantation of normal BM into BALB-neuT mice readily resulted in hypertrophic hematopoiesis with myeloid cell expansion. This persistent influence of the tumor was mediated through the release of vascular endothelial growth factor (VEGF) but not granulocyte-macrophage colony-stimulating factor (GM-CSF), and was down-modulated when tumor load was reduced but not when BM was transplanted. Together, the data obtained in the BALB-neuT model of naturally occurring carcinogenesis show that tumor-associated immune suppression is secondary to a more general alteration of host hematopoiesis, conditioned by tumor-secreted soluble factors.

Animals↗

PubMed2003

LAG-3 enables DNA vaccination to persistently prevent mammary carcinogenesis in HER-2/neu transgenic BALB/c mice.

Within 33 weeks of life, all 10 mammary glands of virgin BALB/c mice transgenic for the transforming rat HER-2/neu oncogene under the mammary tumor virus promoter (BALB-neuT mice) progress from atypical hyperplasia to invasive palpable carcinoma. Repeated DNA vaccination with plasmids coding for the extracellular and transmembrane domain of the protein product of rat HER-2/neu (r-p185(neu)) delayed tumor onset and reduced tumor multiplicity, but this protection eventually declined, and few mice were tumor free at 1 year of age. Association of plasmid vaccination with administration of soluble mouse LAG-3 (lymphocyte activation gene-3/CD223) generated by fusing the extracellular domain of murine LAG-3 to a murine IgG2a Fc portion (mLAG-3Ig) elicited a stronger and sustained protection that kept 70% of 1-year-old mice tumor free. Moreover, this combined vaccination, which was performed when multiple in situ carcinomas were already evident, extended disease-free survival and reduced carcinoma multiplicity. Inhibition of carcinogenesis was associated with markedly reduced epithelial cell proliferation and r-p185(neu) expression, whereas the few remaining hyperplastic foci were heavily infiltrated by reactive leukocytes. A stronger and enduring r-p185(neu)-specific cytotoxicity, a sustained release of IFN-gamma and interleukin 4, and a marked expansion of both CD8(+)/CD11b(+)/CD28(+) effector and CD8(+)/CD11b(+)/CD28(-) memory effector T-cell populations were induced in immunized mice. This combined vaccination also elicited a quicker and higher antibody response to r-p185(neu), as well as an early antibody isotype switch. These data suggest that the appropriate costimulation provided by mLAG-3Ig enables DNA vaccination to establish an effective protection, probably by enhancing cross-presentation of the DNA coded antigen.

Adjuvants, Immunologic↗

PubMed2003

Protein vaccination with the HER2/neu extracellular domain plus anti-HER2/neu antibody-cytokine fusion proteins induces a protective anti-HER2/neu immune response in mice.

Previously protein vaccines consisting of the extracellular domain of HER2/neu (ECD(HER2)) were shown to elicit an immune response that does not provide protection against transplantable tumors expressing HER2/neu. Here, we showed that when mice were vaccinated with a mixture of human ECD(HER2) and anti-human HER2/neu IL-12, IL-2 or GM-CSF fusion proteins, significant retardation of the growth of a syngeneic carcinoma expressing rat HER2/neu, and long-term survivors were observed. Immune sera inhibited the in vitro growth of SK-BR-3, a human breast cancer overexpressing HER2/neu. Transfer of immune sera into mice challenged with TUBO also led to partial inhibition of tumor growth. Splenocytes from mice vaccinated with ECD(HER2) plus IgG3-(GM-CSF) incubated with ECD(HER2) demonstrated significant proliferation and IFN-gamma secretion. Taken together these results suggest that vaccines including ECD(HER2) and Ab-cytokine fusion proteins may be used to elicit both humoral and cell-mediated responses against HER2/neu.

Animals↗

PubMed2003

Cancer immunoprevention: tracking down persistent tumor antigens.

The immune response can effectively hamper the progression of preclinical stages of tumor growth. Medicine in the postgenomic era offers an increasing possibility of detecting healthy individuals at risk of developing cancer who could benefit from tumor-preventive vaccines. The identification of novel tumor antigens that fulfill two conditions will be crucial for the development of cancer immunoprevention. First, an ideal antigen should have a crucial pathogenetic role in tumor growth to avoid the selection of antigen-loss variants. Second, the antigen should be recognizable by the immune system even in MHC-loss variants and should therefore be recognized both by antibodies and T cells. Identifying such antigens will also provide new targets for cancer immunotherapy.

Animals↗

PubMed2003

Immunization in tumor prevention.

Recent experimental data suggest that immunity can be activated to prevent tumors. The rationale for prevention is strong because the setting is one endowed with an immune system that is neither impaired by tumor and treatment-induced suppression, nor tolerant to tumor-associated antigens. Oncogenic growth factor receptors are tumor antigens and rational targets for specific immunoprevention. Successful prevention of mammary carcinomas in Her-2/neu transgenic mice is cited as an evidence of the validity of this approach. The specific properties of the Her-2/neu gene product as an antigen and the nature of the immune responses induced by effective preventive treatments are summarized.

Animals↗

PubMed2003

Nonredundant roles of antibody, cytokines, and perforin in the eradication of established Her-2/neu carcinomas.

Since the mechanisms by which specific immunity destroys Her-2/neu carcinoma cells are highly undetermined, these were assessed in BALB/c mice vaccinated with plasmids encoding extracellular and transmembrane domains of the protein product (p185(neu)) of the rat Her-2/neu oncogene shot into the skin by gene gun. Vaccinated mice rejected a lethal challenge of TUBO carcinoma cells expressing p185(neu). Depletion of CD4 T cells during immunization abolished the protection, while depletion of CD8 cells during the effector phase halved it, and depletion of polymorphonuclear granulocytes abolished all protection. By contrast, Ig mu-chain gene KO mice, as well as Fcgamma receptor I/III, beta-2 microglobulin, CD1, monocyte chemoattractant protein 1 (MCP1), IFN-gamma, and perforin gene KO mice were protected. Only mice with both IFN-gamma and perforin gene KOs were not protected. Although immunization also cured all BALB/c mice bearing established TUBO carcinomas, it did not cure any of the perforin KO or perforin and IFN-gamma KO mice. Few mice were cured that had knockouts of the gene for Ig mu-chain, Fcgamma receptor I/III, IFN-gamma, or beta-2 microglobulin. Moreover, vaccination cured half of the CD1 and the majority of the MCP1 KO mice. The eradication of established p185(neu) carcinomas involves distinct mechanisms, each endowed with a different curative potential.

Animals↗

PubMed2002

Improved survival with perilymphatic interleukin 2 in patients with resectable squamous cell carcinoma of the oral cavity and oropharynx.

BACKGROUND: The current randomized, multicenter, Phase III trial was conducted to determine whether the disease free interval and overall survival of patients with T2-T4,N0-N3,M0 squamous cell carcinoma (SCC) of the oral cavity or oropharynx could be extended through the combination of surgery (and radiotherapy, if required) with perilymphatic recombinant IL-2 (rIL-2). METHODS: Patients with a resectable T2-T4,N0-N3,M0 SCC of the oral cavity and oropharynx were assigned randomly to receive surgery and radiotherapy or to receive IL-2, surgery, and radiotherapy. Five thousand units of rIL-2 were injected around the ipsilateral cervical lymph node chain daily for 10 days before surgery. After surgery, contralateral 5-day rIL-2 courses were administered monthly for 1 year. The differences in disease free and overall survival between the two groups of patients were evaluated statistically. RESULTS: Two hundred two patients finished the study. No significant complications related to rIL-2 were encountered, and surgery and radiotherapy were not hampered by its prior administration. Multivariate analysis conducted to determine the extent to which survival was influenced by rIL-2 and the other variables showed that rIL-2 significantly lengthened disease free survival (P < 0.01) and that this resulted in longer overall survival (P < 0.03). CONCLUSIONS: The data emerging from this trial indicate that perilymphatic administration of low, nontoxic doses of rIL-2 is a simple and manageable way to delay recurrences of SCC.

Adult↗

PubMed2002

Antitumor vaccines: is it possible to prevent a tumor?

The main medical use of vaccines is to induce a state of immunity in healthy individuals to protect them from deadly or dangerous diseases. In the field of cancer immunology, however, vaccines are being used in patients as therapy, often with a very poor success rate against advanced disease. This paper reviews recent preclinical evidence in favor of the prophylactic use of immunological approaches to cancer. Successful attempts at immunological cancer prevention in HER-2/neu transgenic mice are described as an example. The specific properties of the HER-2/neu gene product as a tumor antigen, and the nature of the immune responses induced by effective preventive treatments are reviewed. Although the very high rate of mammary carcinoma prevention in mice has generated enthusiasm, it should not be forgotten that such treatments, when administered to healthy humans at risk of cancer, may carry the risk of inducing autoimmunity. These issues can be addressed in preclinical studies in appropriate animal models.

Animals↗

PubMed2002

Immunological prevention of spontaneous tumors: a new prospect?

Recent demonstrations of the specific immune prevention of mammary cancer in female BALB/c mice transgenic for the rat Her-2/neu oncogene (BALB-neuT) have resulted in reconsideration of the immune mechanisms that inhibit tumor growth. All the mammary glands of these mice progress asynchronously, but consistently, from hyperplasia to invasive carcinoma. Overexpression of the oncogene product p185neu is first evident in the rudimentary glands of 3-week-old mice. Carcinogenesis is prevented by vaccination with plasmids coding for the extracellular and transmembrane domains of this p185neu, or with allogeneic cells expressing p185neu on their membrane, plus the systemic administration of IL-12. This inhibition is the outcome of a delayed-type hypersensitivity specific for p185neu and the production of anti-p185neu antibodies that restrain the proliferation of tumor cells by stripping p185neu from their membrane, whereas cytotoxic T lymphocytes seem devoid of a major role.

Animals↗

PubMed2002

Requirement for both IL-12 and IFN-gamma signaling pathways in optimal IFN-gamma production by human T cells.

Phytohemagglutinin (PHA)-derived T lymphoblasts or T cell clones from patients genetically deficient in IL-12R beta 1 (IL-12R beta 1(-/-)) or IFN-gamma R1 (IFN-gamma R1(-/-)) produced two- to threefold reduced IFN-gamma levels compared to the corresponding cells from healthy individuals after anti-CD3 and PMA stimulation. Moderate IFN-gamma production was observed in PHA-derived T lymphoblasts or T cell clones derived from healthy subjects in the presence of anti-IFN-gamma R1 or anti-IL-12 mAb, whereas it was negligible in the presence of both mAb. However, when anti-IFN-gamma R1 and/or anti-IL-12 mAb were added during restimulation, the cells produced normal levels of IFN-gamma, indicating that both IFN-gamma and IL-12 had an effect on the priming phase. Moderate production of IFN-gamma was partially enhanced only in IFN-gamma R1(-/-) T cell clones generated in the presence of IL-12, but was almost completely abolished when IL-12R beta 1(-/-) and IFN-gamma R1(-/-) T cell clones were generated in the presence of anti-IFN-gamma R1 or anti-IL-12 mAb, respectively. IL-4 production was enhanced in T cell clones from IL-12R beta 1(-/-),but not from IFN-gamma R1(-/-) patients, whereas IL-10 and IL-2 production did not differ significantly in polyclonal T cells or clones from healthy and deficient individuals. These results indicate that IL-12R beta 1- and IFN-gamma R1-dependent signals co-ordinately regulate IFN-gamma, but not IL-2 and IL-10 production, whereas only IL-12 negatively controls IL-4 production by in vitro-generated T cell clones. Thus, although IL-12 and IFN-gamma signals are each sufficient for moderate production of IFN-gamma by human T cells, both are needed for optimal IFN-gamma production, and in the absence of both IFN-gamma production is completely abrogated.

Antibodies, Monoclonal↗

PubMed2002

Immunoprevention of colorectal cancer: a future possibility?

Immunoprevention of colorectal cancer remains a largely untested possibility. The success demonstrated by immunopreventive approaches in mammary carcinoma suggest that this new cancer preventive modality should be investigated for other types of cancer. The design of a successful strategy for colorectal cancer will have to incorporate general concepts that have already been developed for dealing with other tumors, and intestine-specific immunologic strategies.

Adjuvants, Immunologic↗

PubMed2002

Prophylactic cancer vaccines.

Increasingly, data from distinct experimental systems show that immunity can be activated to prevent tumors. The rationale for prevention is strong because, in that setting, one deals with an immune system that is neither impaired by tumor- and treatment-induced suppression nor tolerant to tumor-associated antigens that have been encountered in the absence of correct presentation and costimulatory/danger signals. The use of overexpressed or mutated proteins, or mutated oncogenic growth factor receptors, as tumor-associated antigens yields rational targets for specific immunoprevention. Transgenic mouse models are providing encouraging indications of future usefulness of vaccines that are based on these molecules.

Animals↗

PubMed2002

IFN-gamma and IL-12 differentially regulate CC-chemokine secretion and CCR5 expression in human T lymphocytes.

Interleukin (IL)-12, especially in the presence of neutralizing anti-IL-4 monoclonal antibodies, primed CD45RO(-) T clones for high CCL3/macrophage-inflammatory protein-1alpha (MIP-1alpha) and CCL4/MIP-1beta levels. In CD4(+) and CD8(+) clones from two patients deficient for IL-12Rbeta1 (IL-12Rbeta1(-/-)), production of CCL3/MIP-1alpha and CCL4/MIP-1beta was defective. CD4(+) clones from two patients deficient for interferon-gamma (IFN-gamma) R1 (IFN-gammaR1(-/-)) produced somewhat decreased CCL4/MIP-1beta levels. IL-12 failed to prime CD4(+) or CD8(+) healthy clones for high CCL5/regulated on activation, normal T expressed and secreted (RANTES) production, although its secretion was impaired in CD4(+) clones from IL-12Rbeta1(-/-) and IFN-gammaR1(-/-) patients. CCR5 surface expression was up-regulated in resting peripheral blood mononuclear cells and CD4(+) clones from both kinds of patients, rendering them more susceptible to CCR5-dependent (R5) HIV-1 infection. Neutralization of IFN-gamma increased CCR5 expression and decreased CC-chemokine secretion by CD4(+) clones from healthy and IL-12Rbeta1(-/-) individuals, suggesting an IFN-gamma-dependent control of CCR5 expression. These data provide the first documented analysis of chemokine secretion and chemokine receptor expression on T cells from IL-12 and IFN-gamma receptor-deficient patients and dissect the role of IL-12 and IFN-gamma on inducing inflammatory chemokine secretion and down-regulating CCR5 expression in human T cells.

CD4 Antigens↗

PubMedDate not supplied

Death receptor ligands in tumors.

Activation of apoptosis via death receptors is a tightly regulated event, and the death pathway itself is open to interference on the part of soluble or membrane-bound decoy receptors. The aggregation state of the death-inducing ligand is a crucial factor, particularly when these molecules are used as recombinant drugs against tumors. Whether tumors are sensitive to such ligands is determined by both the net abundance of death receptors versus decoy receptors and the balance between intracellular apoptotic and antiapoptotic mechanisms. This means that in vivo elimination of tumor cells by effector arms such as T lymphocytes, natural killer cells, macrophages, and dendritic cells is dependent on both the function of activated lymphoid cells and the genetic properties of tumor cells. Death receptor ligands, however, may be a double-edged sword. When expressed on cytotoxic T lymphocytes, natural killer cells, monocytes, and dendritic cells, they induce the apoptosis of many tumor cells, whereas their expression on tumor cells induces the apoptosis of killer cells. The in vivo result is influenced by the number of infiltrating cells, their state of activation, the cytokine repertoire in the tumor microenvironment, and the ability of the tumor to produce soluble factors inhibiting their cytolytic functions.

Animals↗

PubMedDate not supplied

Visualization through magnetic resonance imaging of DNA internalized following "in vivo" electroporation.

The ability to visualize plasmid DNA entrapment in muscle cells undergoing an "in vivo" electroporation treatment was investigated on BALB/c mice using a 7-T magnetic resonance imaging (MRI) scanner using the paramagnetic Gd-DOTA-spd complex as imaging reporter. Gd-DOTA-spd bears a tripositively charged spermidine residue that yields a strong binding affinity toward the negatively charged DNA chain (6.4 kb, K(a) = 2.2 x 10(3) M(-1) for approximately 2500 +/- 500 binding sites). Cellular colocalization of Gd-DOTA-spd and plasmid DNA has been validated by histological analysis of excised treated muscle. In vivo MRI visualization of Gd-DOTA-spd distribution provides an excellent route to access the cellular entrapment of plasmid DNA upon applying an electroporation pulse.

Animals↗