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Biomedical subjects

A Dolei

Publications and source records attributed to A Dolei.

At least 19 recordsLinked to original sources
PubMed1992

Interferon-alpha/beta in virus-induced mouse mammary carcinogenesis: effects on the spontaneous process and on the progression of transplanted pre-neoplastic lesions.

Low levels of anti-viral activity, mainly interferon alpha/beta (IFN-alpha/beta), are regularly found in lymphoid tissues of BALB/c mice infected with the C3H strain of mammary tumor virus. At the time of tumor development, significant amounts of anti-viral activity were detected in homogenates of spleen and mammary tumors, but not in blood and normal mammary glands. This activity is pH2-resistant and neutralized by antibody to IFN/alpha-beta. The pathogenetic role of IFN in mammary carcinogenesis was investigated in 2 ways: (a) by treating virus-infected newborn mice with antibody to IFN-alpha/beta, and (b) by giving either the latter antibody or IFN-alpha/beta to virus-free animals transplanted with pre-neoplastic lesions. Mice were treated only for 2 months, starting either 1 week after birth or immediately after tumor transplant. In case (a), treatment with antibody to IFN-alpha/beta shortened the incubation period of mammary carcinomas and decreased the mean survival time. In case (b), anti-IFN antibody did not significantly affect the development of mammary tumors. However, exogenous IFN-alpha/beta markedly reduced both tumor incidence and mortality rate. These results indicate that endogenous IFN-alpha/beta plays a crucial role in the in vivo restriction of the early infectious phase of spontaneous carcinogenesis and that relatively high doses of IFN-alpha/beta may inhibit the progression of pre-neoplastic lesions.

Aging↗
PubMed1992

Regulation of surface-differentiation molecules by epidermal growth factor, transforming growth factor alpha, and hydrocortisone in human mammary epithelial cells transformed by an activated c-Ha-ras proto-oncogene.

Spontaneously immortalized human mammary epithelial cells MCF-10A were transfected with an activated c-Ha-ras oncogene. Transfected cells (MCF-10T) acquire a malignant phenotype, as already reported. Studies of 125I-2'-deoxyuridine incorporation in cultures given graded doses of hydrocortisone (HC), cholera toxin (CT), epidermal growth factor (EGF), and transforming growth factor alpha (TGF-alpha) showed that though MCF-10T had become almost independent on exogenous EGF and TGF-alpha, they continued to respond to the synergistic effect of HC and CT plus EGF. Both lines were phenotypically characterized with an immunoradiometric assay in live cells. Expression of MHC class-I molecules, human milk-fat-globule-I antigen, and EGF receptor was reduced in ras-transfected cells, although other differentiation markers were unchanged. Exogenous EGF down-regulated the expression of functional EGF-R, selectively in transformed cells. TGF-alpha failed to modulate EGF-R. In contrast, HC strongly stimulated the expression of EGF-R while depressing MHC class-I molecules. Thus, it appears that in vivo HC may co-operate with TGF-alpha and EGF in promoting the growth of transformed mammary cells. This hormone might also favor the escape from immune surveillance by reducing the expression of surface differentiation markers.

Antigens, Differentiation↗
PubMed1988

Induction and regulation of cytotoxic T cells by microbial antigens and recombinant interleukin 2.

The proliferation and development of cytotoxic T cells was investigated in human peripheral blood mononuclear cell (PBMC) cultures stimulated with an antigenic extract from Candida albicans (MPPS), or with the purified protein derivative from Mycobacterium tuberculosis (PPD), or with human recombinant interleukin 2 (rIL-2). Microbial antigen- and rIL-2-induced cytotoxic T cells were able to lyse both natural killer (NK) sensitive and resistant targets. No correlation was observed between the development of T cell cytotoxicity and interferon (IFN) production in vitro. The addition of anti-class II monoclonal antibodies at the beginning of MPPS/PPD-stimulated cultures inhibited the cell proliferation, IFN production and T cell cytotoxicity, while all these cellular activities were not inhibited by anti-class II antibodies in rIL-2-stimulated cultures. Finally, antibodies to class I determinants inhibit T cell cytotoxicity, suggesting a role of such determinants in the development of the non-adaptive immunity to microbial infections.

Adult↗
PubMed1986

A new type of human interferon produced by peripheral blood mononuclear cells treated with inhibitors of transcription.

Peripheral blood mononuclear cells from human normal donors treated with inhibitors of transcription produce a protein with the properties of interferon (IFN) [activity against a broad range of viruses, species specificity, lack of blockade of virus attachment, capability to induce in cells durable antiviral state, establishment of antiviral state requiring ongoing protein and RNA synthesis, capability to induce 2',5'-oligoadenylate synthetase]. This IFN-like protein has a molecular weight of approximately 7000 daltons and is not neutralized by antibody to alpha-, beta-, and gamma-IFNs tested singularly or in a pooled fashion. Taken together the data suggest that this IFN-like protein may indeed be a new type of human IFN.

2',5'-Oligoadenylate Synthetase↗
PubMed1986

Direct and cell-mediated effects of interferon-alpha and -gamma on cells chronically infected with HTLV-III.

The replication of the human T lymphotropic retrovirus HTLV-III in persistently infected cells is relatively insensitive to the direct antiviral action of human interferon-alpha or -gamma (IFN-alpha or -gamma), showing only a two- to threefold reduction of HTLV-III, even though the host cells are very sensitive to IFN, as shown by vesicular stomatitis virus (VSV)-yield reduction assay (4-5 log reduction of VSV). However, IFN anticellular activity is strongly enhanced in the presence of normal peripheral blood mononuclear cells, suggesting a cell-mediated effect of IFNs.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Effects of dexamethasone on human natural killer cell cytotoxicity, interferon production, and interleukin-2 receptor expression induced by microbial antigens.

Dexamethasone inhibits the expression of the interleukin-2 receptor, the synthesis of immune interferon, and the development of natural killer cells when added to peripheral blood mononuclear cells cultured with soluble microbial antigens (purified protein derivative and a polysaccharide extract from Candida albicans [MPPS]) or human recombinant interleukin-2.

Antigens, Bacterial↗
PubMed1986

Regulation of immune interferon production during the response to soluble microbial antigens.

Human peripheral blood mononuclear cells (PBMC) stimulated in vitro with purified protein derivative (PPD) or with a Candida albicans polysaccharide extract (MPPS) released immune interferon (IFN) and interleukin 2 (IL-2). Kinetic studies showed a biphasic production of IFN with maximum levels at days 3-4 and days 5-6 of culture. In contrast, the IL-2 production is only observed at days 2-3 of culture. The relationship between IFN and IL-2, analysed both in responder and nonresponder PBMC cultures, showed that the early peak of IFN production appears to be IL-2 independent whereas the second peak seems strictly related to the presence of IL-2 culture. Furthermore, monoclonal antibodies against class I and class II products of the major histocompatibility complex (MHC) inhibited IFN production when added at the beginning of culture, whereas only anti-class I antibodies interfered with the release of IFN when added to antigen-primed lymphocytes.

Adult↗
PubMed1985

Differences in the expression and release of DR, BR, and DQ molecules in human cells treated with recombinant interferon gamma: comparison to other interferons.

This study presents a comparative analysis of the effects of different interferons (IFN) on the three recognizable subsets of human HLA class II molecules: DR, BR, and DQ. Both cellular expression and shedding of class II molecules have been determined on three different cell types. The results can be summarized as follows: class II molecules are markedly increased by IFN gamma; IFN beta has a lower enhancing effect, and IFN alpha has only a slight, if any, effect. Kinetically, the action of IFN gamma is prompter and longer lasting than that of IFN beta. DQ expression is much more enhanced by IFN gamma than either DR or BR; IFN beta has the same effect on all three subsets. Parallel changes of the cellular expression and of the shedding of these molecules are observed. A melanoma and a lymphoblastoid cell line and peripheral blood mononuclear cells show qualitatively similar modifications.

B-Lymphocytes↗
PubMed1979

Nuclear RNA sequences coding for alpha and beta globins in erythroid cells: evidence for multiple intermediate molecules.

The poly (A)-containing nuclear RNA from dimethylsulfoxide-induced Friend leukemia cells was fractionated by acrylamide gel electrophoresis in denaturing conditions and analyzed for alpha and beta globin RNA sequences. The results indicate that nuclear RNA contains one species of large-size RNA (0.6 X 10(6) daltons), which is the putative precursor for beta globin mRNA only. In addition, it was shown by electrophoretic analysis that the complex of RNA molecules not resolved by sucrose gradient centrifugation (11S) comprises sequences of decreasing size (0.34, 0.28, and 0.26 X 10(6) daltons), which might be the precursors of alpha and beta globin mRNA.

Erythrocytes↗
PubMed1977

Inhibition of transcription and translation of globin messenger RNA in dimethyl sulfoxide-stimulated Friend erythroleukemic cells treated with interferon.

The addition of appropriate doses of interferon (IF) to cultures of Friend erythroleukemic cells inhibits dimethyl sulfoxide (Me2SO)-stimulated erythroid differentiation. In this study, the synthesis of heme, hemoglobin, and globin mRNA in Me2SO-stimulated cultures, with or without IF added, was compared. Although the hemoglobin content in Me2SO+IF-treated cultures was reduced 6- to 9-fold compared to that of cultures treated with Me2SO alone, there was less than a 2-fold decrease in the amount of heme accumulated. Globin mRNA, although unchanged in size or base sequence, was reduced in content in the Me2SO+IF cultures. The level of reduction of globin mRNA was insufficient to account for the lack of globin synthesis. Thus, it appears that IF may operate on two levels--one involving the transcription of globin mRNA and the other involving its translation.

Animals↗