scholarly journals Class II histocompatibility antigen expression in human melanocytes transformed by Harvey murine sarcoma virus (Ha-MSV) and Kirsten MSV retroviruses.

1986 ◽  
Vol 164 (5) ◽  
pp. 1710-1722 ◽  
Author(s):  
A P Albino ◽  
A N Houghton ◽  
M Eisinger ◽  
J S Lee ◽  
R R Kantor ◽  
...  
Keyword(s):  
Antigen Expression ◽  
Fold Increase ◽  
Surface Expression ◽  
Class Ii ◽  
Soft Agar ◽  
Cell Surface Expression ◽  
Ia Antigens ◽  
Human Melanocytes ◽  
Murine Sarcoma Virus ◽  
Sarcoma Virus

Human melanocytes infected with Ki-MSV or Ha-MSV, but not amphotropic MuLV, undergo a series of transformation-related changes that are characteristic of malignant melanoma. These are (a) expression of Ia antigens, in particular DP, DQ, and DR class II histocompatibility gene products, (b) a transformed morphology and ability to grow in soft agar, and (c) a 5-10-fold increase in the cell surface expression of GD3 ganglioside. However, other characteristics of melanoma, such as independence from specific growth factors and loss of adenosine deaminase binding protein were not observed. We conclude that viral ras oncogenes initiate early transformation events in melanocytes, and that Ia antigen expression is a transformation marker in this system.

scholarly journals Kirsten murine sarcoma virus abolishes interferon gamma-induced class II but not class I major histocompatibility antigen expression in a murine fibroblast line.

1988 ◽  
Vol 167 (2) ◽  
pp. 706-711 ◽  
Author(s):  
D J Maudsley ◽  
A G Morris
Keyword(s):  
Leukemia Virus ◽  
Constitutive Expression ◽  
Antigen Expression ◽  
Class Ii ◽  
Class I ◽  
Ras Gene ◽  
Ifn Gamma ◽  
Murine Sarcoma Virus ◽  
Sarcoma Virus ◽  
Murine Sarcoma

The effect of infecting fibroblasts with Kirsten murine sarcoma virus/murine leukemia virus (Ki-MSV/MLV) on constitutive and IFN-gamma-induced H-2 antigen expression was investigated. The fibroblasts used were two established cell lines (C3H10T1/2 and BALB/c3T3) and fresh embryo fibroblasts from C3H mice. Class I antigens were expressed constitutively by BALB/c3T3; infection with MLV, MSV or the two together had little effect on this constitutive expression. Class I antigens (H-2K, H-2D) were strongly induced on all three types of fibroblast by rIFN-gamma, and infection had little effect on this. None of the fibroblasts expressed constitutively detectable levels of class II antigen; however, C3H10T1/2 fibroblasts could be induced for both H-2A and H-2E by IFN-gamma. Infection of C3H10T1/2 with helper-free Ki-MSV, or MSV together with MLV, completely abolished this induction of class II antigens, while infection with MLV alone had little effect, implying that the abolition of class II induction was due to genomic regions of Ki-MSV not shared with Ki-MLV, probably the v-Ki-ras gene.

Increased Expression of u-PA and u-PAR on Monocytes by LDL and Lp(a) Lipoproteins – Consequences for Plasmin Generation and Monocyte Adhesion

1999 ◽  
Vol 81 (04) ◽  
pp. 594-560 ◽  
Author(s):  
Florence Ganné ◽  
Marc Vasse ◽  
Jean-Louis Beaudeu ◽  
Jacqueline Peynet ◽  
Arnaud François ◽  
...  
Keyword(s):  
Fold Increase ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Atheromatous Plaque ◽  
Monocyte Adhesion ◽  
Blood Monocytes ◽  
Proteolytic Cascade ◽  
Ecm Degradation ◽  
Dose Dependent Increase ◽  
Dose Dependent

SummaryMonocyte-derived foam cells figure prominently in rupture-prone regions of atherosclerotic plaque. As urokinase/urokinase-receptor (u-PA/u-PAR) is the trigger of a proteolytic cascade responsible for ECM degradation, we have examined the effect of atherogenic lipoproteins on monocyte surface expression of u-PAR and u-PA. Peripheral blood monocytes, isolated from 10 healthy volunteers, were incubated with 10 to 200 µg/ml of native or oxidised (ox-) atherogenous lipoproteins for 18 h and cell surface expression of u-PA and u-PAR was analysed by flow cytometry. Both LDL and Lp(a) induced a dose-dependent increase in u-PA (1.6-fold increase with 200 μg/ml of ox-LDL) and u-PAR [1.7-fold increase with 200 μg/ml of ox-Lp(a)]. There is a great variability of the response among the donors, some of them remaining non-responders (absence of increase of u-PA or u-PAR) even at 200 μg/ml of lipoproteins. In positive responders, enhanced u-PA/u-PAR is associated with a significant increase of plasmin generation (1.9-fold increase with 200 μg/ml of ox-LDL), as determined by an amidolytic assay. Furthermore, monocyte adhesion to vitronectin and fibrinogen was significantly enhanced by the lipoproteins [respectively 2-fold and 1.7-fold increase with 200 μg/ml of ox-Lp(a)], due to the increase of u-PAR and ICAM-1, which are receptors for vitronectin and fibrinogen. These data suggest that atherogenous lipoproteins could contribute to the development of atheromatous plaque by increasing monocyte adhesion and trigger plaque weakening by inducing ECM degradation.

Revertants of v-fos-transformed rat fibroblasts: suppression of transformation is dominant

1990 ◽  
Vol 10 (11) ◽  
pp. 5626-5633
Author(s):  
R Wisdom ◽  
I M Verma
Keyword(s):  
Divalent Cations ◽  
Simian Virus 40 ◽  
Soft Agar ◽  
Simian Virus ◽  
Ras Gene ◽  
Recessive Mutations ◽  
Activating Mutation ◽  
Murine Sarcoma Virus ◽  
Sarcoma Virus ◽  
Rat Fibroblasts

Phenotypic revertants of Finkel-Biskis-Riley (FBR)-murine sarcoma virus-transformed rat fibroblasts were isolated on the basis of their adherence to plastic tissue culture dishes in the absence of divalent cations. Some revertants had sustained deletions or inactivating mutations of the v-fos gene. However, two revertants expressed a functional v-fos gene at levels equal to that in the transformed parental cells, and therefore phenotypic reversion was due to mutations in nonviral genes. These revertants were considered nontransformed according to four criteria: (i) they were flat and had a nontransformed morphology, (ii) they were contact inhibited when grown to confluence, (iii) they did not display anchorage-independent growth in soft agar, and (iv) they did not form tumors in nude mice. Somatic-cell hybrids between the revertants and the transformed parental cells were nontransformed, suggesting that the revertants had sustained an activating mutation of a gene capable of suppressing transformation. The expression of c-jun, junB, and junD was not altered in the revertants, and they could not be transformed by transfection with a c-jun expression vector. The revertants were resistant to transformation by an activated c-Ha-ras gene but were susceptible to transformation by simian virus 40. Our results demonstrate the existence of a class of revertants that harbor genes capable of suppressing transformation by v-fos and some other oncogenes. This contrasts with previously described revertants of transformation by v-fos that contain recessive mutations.

scholarly journals Analysis of functional domains of the v-fms-encoded protein of Susan McDonough strain feline sarcoma virus by linker insertion mutagenesis.

1987 ◽  
Vol 7 (9) ◽  
pp. 3287-3296 ◽  
Author(s):  
S D Lyman ◽  
L R Rohrschneider
Keyword(s):  
Cell Surface ◽  
Biological Effects ◽  
Intracellular Localization ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Insertion Mutagenesis ◽  
Focus Formation ◽  
External Domain ◽  
Sarcoma Virus

The Susan McDonough strain of feline sarcoma virus contains an oncogene, v-fms, which is capable of transforming fibroblasts in vitro. The mature protein product of the v-fms gene (gp140fms) is found on the surface of transformed cells; this glycoprotein has external, transmembrane, and cytoplasmic domains. To assess the functional role of these domains in transformation, we constructed a series of nine linker insertion mutations throughout the v-fms gene by using a dodecameric BamHI linker. The biological effects of these mutations on the function and intracellular localization of v-fms-encoded proteins were determined by transfecting the mutated DNA into Rat-2 cells. Most of the mutations within the external domain of the v-fms-encoded protein eliminated focus formation on Rat-2 cells; three of these mutations interfered with the glycosylation of the v-fms protein and interfered with formation of the mature gp140fms. One mutation in the external domain led to cell surface expression of v-fms protein even in the absence of complete glycosylational processing. Cell surface expression of mutated v-fms protein is probably necessary, but is not sufficient, for cell transformation since mutant v-fms protein was found on the surface of several nontransformed cell lines. Mutations that were introduced within the external domain had little effect on in vitro kinase activity, whereas mutations within the cytoplasmic domain all had strong inhibitory effects on this activity.

From transcription to cell surface expression, the induction of MHC class II I-Aα by interferon-γ in macrophages is regulated at different levels

2001 ◽  
Vol 53 (2) ◽  
pp. 136-144 ◽  
Author(s):  
Martin Cullell-Young ◽  
Marta Barrachina ◽  
Carlos López-López ◽  
Eduard Goñalons ◽  
Jorge Lloberas ◽  
...  
Keyword(s):  
Cell Surface ◽  
Mhc Class Ii ◽  
Surface Expression ◽  
Class Ii ◽  
Interferon Γ ◽  
Cell Surface Expression ◽  
Different Levels

scholarly journals Edmonston Measles Virus Prevents Increased Cell Surface Expression of Peptide-Loaded Major Histocompatibility Complex Class II Proteins in Human Peripheral Monocytes

2003 ◽  
Vol 77 (17) ◽  
pp. 9412-9421 ◽  
Author(s):  
Mamadi Yilla ◽  
Carole Hickman ◽  
Marcia McGrew ◽  
Elizabeth Meade ◽  
William J. Bellini
Keyword(s):  
Major Histocompatibility Complex ◽  
Protein Expression ◽  
Mhc Class Ii ◽  
Measles Virus ◽  
Surface Expression ◽  
Class Ii ◽  
Class I ◽  
Cell Surface Expression ◽  
Histocompatibility Complex ◽  
Ifn Γ

ABSTRACT Gamma interferon (IFN-γ) induces expression of the gene products of the major histocompatibility complex (MHC), whereas IFN-α/β can interfere with or suppress class II protein expression. In separate studies, measles virus (MV) was reported to induce IFN-α/β and to up-regulate MHC class II proteins. In an attempt to resolve this paradox, we examined the surface expression of MHC class I and class II proteins in MV-infected peripheral monocytes in the presence and absence of IFN-α/β. Infection of purified monocytes with Edmonston B MV resulted in an apparent increase in cell surface expression of HLA-A, -B, and -C class I proteins, but it had no effect on the expression of HLA-DR class II proteins. MV-infected purified monocytes expressed IFN-α/β, but no measurable IFN-γ expression was detected in supernatant fluids. Class II protein expression could be enhanced by coculture of purified monocytes with uninfected peripheral blood mononuclear cell (PBMC) supernatant. MV infection of PBMCs also did not affect expression of class II proteins, but the expression of HLA-A, -B, and -C class I proteins was increased two- to threefold in most donor cells. A direct role for IFN-α/β suppression of MHC class II protein expression was not evident in monocytes since MV suppressed class II protein expression in the absence of IFN-α/β. Taken together, these data suggest that MV interferes with the expression of peptide-loaded class II complexes, an effect that may potentially alter CD4+-T-cell proliferation and the cell-mediated immune responses that they help to regulate.

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