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C Devaux

Publications and source records attributed to C Devaux.

At least 109 records · Page 6Linked to original sources
PubMed1991

Identification of a major human immunodeficiency virus-1 reverse transcriptase epitope recognized by mouse CD4+ T lymphocytes.

Delineation of major T helper cell recognition sites of human immunodeficiency virus (HIV-1) proteins represents one important step in the design of an efficient acquired immune deficiency syndrome (AIDS) vaccine. Towards this end, we have explored the immunogenicity of HIV-1BRU proteins in the mouse model. Preliminary experiments revealed that inbred mice primed with whole inactivated HIV-1 developed strong CD4+ T cell proliferative responses to a variety of recombinant viral proteins including reverse transcriptase (RT). To characterize further the mouse T cell responses to this protein, several Ad- or Ed-restricted T hybridoma cells (THC) were established from BALB/c or DBA/2 mice. These THC were tested for their capacity to recognize a series of 15-mer synthetic overlapping peptides spanning three segments of HIV-1 RT that had been preselected on the basis of either alpha-helicity, amphipaticity, and/or for containing rare amino acid sequence patterns. Peptides corresponding to a C-terminal region (residues 528-560) of RT were recognized by several of the THC established from RT-primed mice. Furthermore, a non-alpha-helical peptide from this region (A3, 528-543) was capable of priming mice with different H-2 haplotypes for both peptide A3 and native RT CD4+ T cell recognition. In addition to the recently identified RT determinant 203-219 capable of triggering both mouse and human CD8+ CTL, the present results identify a good candidate for an immunodominant RT epitope capable of eliciting RT-specific T helper cell responses.

Animals↗
PubMed1991

Surface CD4 density remains constant on lymphocytes of HIV-infected patients in the progression of disease.

In an attempt to question the influence of circulating virus, soluble gp120 or CD4 self-reacting antibodies upon results of CD4+ T-cell immunophenotyping in AIDS patients, five anti-CD4 mAb defining several epitopes of the V1 and V2 domains of the CD4 molecule were used to analyse the epitopic density of CD4 on lymphocytes of seropositive patients taken at stages II, III and IV of HIV infection, according to the Centers for Disease Control (CDC, Atlanta) classification. Our results demonstrate that each CD4 epitopic density measured on circulating lymphocytes remains constant at a mean level of 46,000 epitopes per cell whatever the stage of the disease and whatever the serum p25 concentration. These data provide evidence that antibody accessibility to several CD4 epitopes is not altered by putative interactions between CD4 molecules and circulating virus, soluble gp120 or anti-CD4 autoantibodies. If such binding events, as expected, do occur in vivo, they are of too low a magnitude to influence the immunophenotyping. Furthermore, we show that mAb specific for different epitopes in the V1 and V2 domains of the CD4 molecule can be used interchangeably for the biological followup of the CD4+ cell population in blood samples of HIV-infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Structure of adenovirus fibre. I. Analysis of crystals of fibre from adenovirus serotypes 2 and 5 by electron microscopy and X-ray crystallography.

An analysis by electron microscopy in amorphous ice and X-ray diffraction of four types of three-dimensional crystals of adenovirus fibre is presented. Fibre from adenovirus type 2 (Ad2) crystallizes in two forms depending on whether it is native or cleaved near the N terminus at Tyr17. Fibre from Ad5 also crystallizes in two forms, both of which contained fibre cleaved at Tyr17. Analysis of the packing of the fibres in each of these crystals suggests that the overall length of the fibre may be considerably longer (about 350 to 370 A) than previously reported. Crystals of cleaved Ad2 fibre are of sufficient quality to be characterized by X-ray diffraction. They are of space group C2 and cell dimensions a = 134.4 A, b = 77.6 A, c = 539.4 A, beta = 92.7 degrees. These crystals are remarkable in that, despite being monoclinic, the ab plane forms a perfect hexagonal lattice. This is explained by a trigonal packing of the trimeric fibre heads in the crystal. A similar feature is found for one type of Ad5 crystal, although the hexagonal lattice is 12% smaller. The crystals of cleaved Ad2 show very strong meridional intensity at a Bragg spacing of 4.4 A and weaker diffuse intensity corresponding to layer-lines of spacing 26.4 A. This must reflect the quasiperiodicity of the structure of the fibre shaft, which is apparent in the primary sequence. The occurrence of these features combined with the new determination of the length of the fibre (see also the accompanying paper) require a reappraisal of the cross-beta model of the fibre shaft proposed by Green et al.

Adenoviridae↗
PubMed1990

Characterization of monoclonal antibodies directed against distinct conserved epitopes of human immunodeficiency virus type 1 core proteins.

Two mouse hybridoma cell lines secreting antibodies to the Human Immunodeficiency Virus (HIV) p25 major core protein and its precursors p55 and p41, were developed after immunization with the highly cytopathic Zaïrian HIV-1 isolate, NDK. These monoclonal antibodies also react with the gag gene products from HIV-1-BRU prototype and present cross reaction with HIV-2-ROD, and SIV-AGM. They map into topographically distinct areas of p25 and define epitopic regions topographically separated from those recognized by four other anti-p25 mAb suggesting the existence of at least 6 spatially distinct epitopic regions on HIV-1-p25 core protein.

Animals↗
PubMed1990

An early postinfection signal mediated by monoclonal anti-beta 2 microglobulin antibody is responsible for delayed production of human immunodeficiency virus type 1 in peripheral blood mononuclear cells.

We recently found (C. Devaux, J. Boucraut, G. Poirier, P. Corbeau, F. Rey, M. Benkirane, B. Perarneau, F. Kourilsky, and J.C. Chermann, submitted for publication) a latency in the human immunodeficiency virus (HIV) type 1 cytopathic effect in the human T-cell lymphotropic virus type I immortalized T-cell line MT4 that was mediated by anti-beta 2 microglobulin (beta 2m) monoclonal antibodies (MAb). Here we describe a delay in viral particle production in peripheral blood mononuclear cells (PBMC) that was mediated by three (B1-1G6, B2-62-2, and HC11-151-1) of four anti-beta 2m MAb tested, the nonefficient MAb (C21-48A) being specific for an epitope on beta 2m that was masked by association with the human leukocyte antigen class I heavy chain. Experiments were designed to determine the mechanism of interference. PBMC incubated with anti-beta 2m MAb before viral exposure were not protected from HIV infection. In addition, anti-beta 2m MAb were not efficient in preventing syncytium formation between HIV-infected PBMC and CD4-positive MT4 cells. In contrast, anti-beta 2m MAb treatment of freshly infected PBMC significantly delayed HIV production in these cells. The window of cell sensitivity to anti-beta 2m MAb treatment took place during a very early post-HIV-binding stage. The possible mechanism of anti-beta 2m MAb action is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Differences in the release of 5'-nucleotidase and alkaline phosphatase from plasma membrane of several cell types by PI-PLC.

1. We have compared the effect of phosphatidyl inositol specific phospholipase C (PI-PLC) on the attachment of both 5'-nucleotidase and alkaline phosphatase to the liver plasma membrane from different species. 2. Our results demonstrate differences in the susceptibilities of both enzymes to PI-PLC treatment in relation to their origin. 3. These results were confirmed by immunoblotting using polyclonal anti-5'-nucleotidase antibodies. 4. In addition, in a single animal, susceptibility of both enzymes to PI-PLC treatment is different from one tissue to another. 5. The different percentages of released enzymes could be explained either by a polymorphism in the anchoring of these proteins at the cell surface membrane, or by a different steric hindrance or environment at the cleavage site itself.

5'-Nucleotidase↗
PubMed1989

Establishment and characterization of mouse thymic epithelial cell lines.

Primary stromal cell cultures from fetal day-16 thymuses of Swiss mice were developed using a combination of D-valine-containing DMEM and Ham's F-12 medium supplemented with epidermal growth factor, insulin and cortisone. Using cloning cylinders and subsequent limiting dilution techniques, we obtained two clones, MTE-1 and MTE-2. The presence of cytokeratin filaments established their epithelial origin. These cells expressed class I and class II MHC antigens after induction by gamma-interferon, and lacked conventional lymphoid cell-surface markers. Their ability to form rosettes with thymocytes should allow us to identify cell-surface antigens involved in thymocyte-epithelial cell interaction. Moreover, these lines will be used to set up in vitro thymocyte maturation assays.

Animals↗
PubMed1987

Evidence that murine hematopoietic cell subset marker J11d is attached to a glycosyl-phosphatidylinositol membrane anchor.

Glycosyl-phosphatidylinositol (G-PI) has been shown to serve as membrane anchor for cell surface molecules such as Thy-1, Ly-6-controlled ThB and Qa antigens. Here, we present several lines of evidence indicating that the hematopoietic cell lineage (i.e. thymocytes, B cell subset and red blood cells) marker defined by the rat monoclonal antibody J11d is also a G-PI-linked structure. First, surface expression of the J11d-defined molecules, and that of the related antigen B2A2, was found to be specifically reduced by treatment of thymocytes and B lymphoma or hybridoma cells with excess of Staphylococcus aureus PI-specific phospholipase C; this enzyme also solubilizes a 35-40-kDa material from erythrocyte microsomal membranes corresponding to the predominant J11d-reactive red cell surface molecules. Second, Thy-1- mutants of the BW5147, T1M1, S1A or S49 murine T lymphoma cells of the complementary classes A, B, C and E (i.e. shown to be defective in the enzymatic machinery that posttranslationally modify Thy-1 molecules) also lack J11d, or express it at a very low level. Although directed at a G-PI-linked structure, the J11d monoclonal antibody, unlike other reagents to Thy-1 or Ly-6-controlled antigens, failed to induce thymocyte proliferation even in the presence of phorbol myristate acetate and cross-linker monoclonal antibody.

Animals↗
PubMed1987

Crystallization, enzymatic cleavage, and the polarity of the adenovirus type 2 fiber.

Crystals of the fiber protein of adenovirus type 2 have been grown. Analysis of these crystals (type I crystals) showed that they were composed of fiber polypeptide with a lower apparent molecular weight (60 kDa) than that of the soluble or virion-incorporated fiber (62 kDa). N-terminal sequencing revealed that the fiber polypeptide chain of 60 kDa was cleaved at tyrosine17 from the N-end. The C-terminus remained intact. Assays with protease inhibitors suggested that the spontaneous cleavage of the fiber occurring upon its crystallization was due to a cellular, calcium-dependent, chymotrypsin-like protease co-purifying with the fiber and activated during hydroxyapatite chromatography. Crystallization of fiber purified in the presence of chymostatin provided crystals of a different structure under the electron microscope (crystals of type II), composed of 62-kDa fiber polypeptide units. The 62-kDa fiber from the type II crystals, as well as the 62-kDa fiber isolated from infected cell extracts, were able to associate with the penton base in vitro to form a penton capsomer. The 60-kDa fiber has lost this capacity. The accessibility of the N- and C-termini of the fiber inside the penton structure was probed by anti-peptide sera after limited proteolysis. The results are consistent with a polarity of the fiber in which its N-terminus is oriented toward the penton base, the C-terminal domain corresponding to the distal knob.

Adenoviruses, Human↗
PubMed1986

Analysis of immunoglobulins expressing the V kappa 21E and V kappa 21D gene products. Evidence for multigenic control of the expression of VH-VL combinations.

The aim of this work was to study the genetic control of VH-VL combined expression. To this end immunoglobulins expressing the V kappa 21E and V kappa 21D gene products were isolated from the normal sera of several inbred strains of mice using a monoclonal antibody that selectively reacts with V kappa 21E and V kappa 21D subgroups. Analysis of the isoelectric focusing (IEF) pattern of the IgG heavy chains of these immunoglobulins obtained from H-2-congeneic mice revealed as expected that Igh-linked loci strongly influence VH-VL combined expression. The IEF pattern of V kappa 21D and V kappa 21E-associated heavy chains isolated from recombinant inbred mouse strains, however, revealed different phenotypes from either parental strains in strains in which both H-2 and Igh loci segregated from the same parent. These data, therefore, strongly suggest that the expression of VH-VL combinations is controlled in part by genetic loci which segregate independently from those linked to H-2 and Igh.

Animals↗
PubMed1985

Electrophoretic characterization of active renin from human kidney and inactive renin from a human chorionic cell culture.

Enzymatically inactive human renin from chorionic cells in culture is significantly distinct in polyacrylamide gel electrophoresis (pH 8.17, 0 degree C) from active human kidney renin. The inactive renin is larger and more basic than the active renin; their molecular weights derived from gel electrophoretic retardation coefficients relate as 47.5/35.3 kDa, their valences (net protons/molecule) as 2.14/1.85. In gel electrofocusing conducted in a mixture of simple buffers, both inactive and active renins exhibit 2 components at the steady-state. The molecular size and basicity of inactive renin are consistent with the hypothesis that it may be a precursor (prorenin), although the possibility that it is an inhibitor complex cannot be ruled out.

Cells, Cultured↗
PubMed1985

Preferential expression of VK21E light chains on IdX Ia.7 positive monoclonal anti-I-E antibodies.

We previously characterized major (IdX Ia.7) and minor (IdI) idiotopes in a collection of monoclonal alloantibodies reactive with monomorphic (i.e., Ia.7-like) determinants in the structural domain I of the murine class II I-E molecules. In this report, preliminary structural characterization of this antibody family is presented. First, the contribution of isolated H and L chains of the anti-Ia.7 cluster I mAb 41.A to IdX Ia.7 and IdI 41.A idiotope expression was evaluated by testing the capacity of these chains, either isolated or reassociated in homologous or heterologous hybrid Ig, to inhibit the binding of rat or mouse anti-idiotope mAb to IdX Ia.7+ mAb coated plates. It was found that the IdI 41.A idiotope defined by the mouse anti-idiotopic mAb H90-21.1 required the presence of both 41.A H and L chains for complete expression, while the rat mAb-defined IdX Ia.7 idiotope could be detected on isolated and on reassociated 41.A L chain. To evaluate further the structural correlates of the IdX Ia.7 idiotope, H, L, or both H and L chains of 5 A.BY, 4 A.TH and 1 C3H.SW IdX+ anti-Ia.7 mAb, as well as that of 3 A.TH IdX- anti-I-E or anti-I-A and -I-E mAb were subjected to NH2-terminal amino acid sequencing. These analyses demonstrated a) that different H chains corresponding to different subgroups (at least to the VHII and VHIII) could be expressed without apparent modification of IdX Ia.7 idiotope expression and b) that 9 of 11 IdX+ anti-Ia.7 mAb utilized highly homologous L chains of the VK21E subgroup. The relevance of these findings to the genetic control of the idiotypic markers identified in the Ia.7 system is discussed.

Amino Acid Sequence↗
PubMed1984

Renin biosynthesis by human tumoral juxtaglomerular cells. Evidences for a renin precursor.

Renin biosynthesis was studied in a juxtaglomerular cell tumor. The tumoral tissue had a high renin content (180 Goldblatt Units/g of tissue), was heavily stained by immunofluorescence using human renin antiserum, and exhibited numerous characteristic secretory granules by electron microscopy. In one series of experiments, renin biosynthesis was studied in tissue slices, by following the incorporation of radiolabeled amino acids into specific immunoprecipitable renin. Time course studies showed that renin was first synthesized in a high molecular weight form, 55,000 mol wt, i.e., 10,000 mol wt higher than that of active renin, and was then converted into a 44,000-mol wt form. In a second series of experiments renin tumoral cells were cultured. Small, round, birefringent cells obtained after collagenase digestion produced renin in both primary culture and subculture media. After 5 d most of the renin found in the culture medium was inactive, but could be activated by trypsin treatment. The tumoral tissue exhibited a strong renin immunofluorescence and numerous secretory granules were observed by electron microscopy. In contrast, the renin-producing cells isolated from this tumor and grown in culture showed little renin immunofluorescence and no secretory granule could be observed. The renin-producing cells in primary culture and subculture were pulsed with radiolabeled amino acids, and immunoprecipitable radiolabeled renin was found in the culture media, thus demonstrating the actual biosynthesis of the enzyme. This renin was not stored inside cultured cells but was rapidly released into the medium and had a molecular weight of 55,000. No conversion of this inactive high molecular weight renin into the active, 44,000 mol wt form of renin was observed. We postulate the existence of two pathways for the processing, packaging, and secretion of renin in the tumoral cells: in juxtaglomerular cells of tumoral tissue renin is synthesized as a preprorenin and rapidly converted into prorenin (55,000 mol wt), which is in turn packaged in secretory granules where it is processed into active renin (44,000 mol wt) and finally secreted; in the cultured tumoral cells renin is still biosynthesized as a preprorenin molecule and then converted into prorenin, but is neither stored as granules nor processed into active renin. In this case the renin is released in an inactive form.

Adult↗
PubMed1984

New monoclonal antibodies directed against human renin. Powerful tools for the investigation of the renin system.

Monoclonal antibodies directed against human renin were obtained by the fusing of myeloma cells with spleen cells from Balb/c or high-responder Biozzi mice injected with pure tumoral or highly purified renal renin. These procedures resulted in the production of seven stable monoclonal antibodies to human renin. Antibodies in the hybridoma culture medium were screened by binding to pure iodinated renin or insolubilized renin in a solid phase assay. The concentration of purified antibodies that provided a 50% binding to iodinated renin varied from 1 X 10(-10) to 1 X 10(-7) M. Two monoclonal antibodies were found to be potent inhibitors of renin enzymatic activity in vitro, behaving as noncompetitive inhibitors (Ki, 1 to 4 X 10(-10) M). They were specific for primate renin. Three monoclonal antibodies provided suitable immunoadsorbants for renin purification. One of these immunoadsorbants was used for large-scale purification of the renal enzyme, resulting in an 825-fold renin enrichment in a single step. Two antibodies were able to distinguish between active and inactive renin and enabled concomitant separation and purification of the two enzyme forms in various biological fluids. Monoclonal antibodies also stained human and monkey renal renin when indirect immunofluorescence and peroxidase-antiperoxidase techniques were used. A highly sensitive radioimmunometric assay of renin was constructed with two monoclonal antibodies. The sensitivity of this improved assay should permit the detection of renin in normal human plasma. Monoclonal antibodies have been shown to be superior to polyclonal antibodies in the following areas: the separation of active from inactive renin, the purification of renin from biological fluids, and the setting up of a direct assay of plasma renin.

Amniotic Fluid↗
PubMed1984

Shared idiotope on monoclonal anti-Ia.7 antibodies reactive with determinants in a structural domain of the I-E molecules.

In previous studies, heterologous anti-idiotypic (anti-Id) antisera against the C3H.SW 14-4-4S or the A.TH 41.A anti-Ia.7 monoclonal antibodies (mAb) were shown to identify an interstrain cross-reactive idiotypic specificity (IdX.Ia.7) expressed on monoclonal or conventional anti-Ia.7 alloantibodies. The objective of the present investigation was to characterize further this IdX at the idiotopic level. To this end, 11 hybridomas producing IgG1, IgG2a, or IgM anti-Id mAb were derived from a rat immunized with a mixture of 10 A.TH or A.BY anti-Ia.7 mAb. The specificity of the latter anti-Id mAb was determined by direct Id binding radioimmunoassay (RIA) with the use of a panel of 52 anti-Ia mAb derived from hybridomas produced in various inbred mouse strains. These rat anti-Id mAb recognized idiotopes expressed on i) all anti-Ia.7 mAb against determinants in the topographic domain I of the I-Ek molecule but not on 18 other anti-I-Ek mAb directed at epitopes in domains II or III; ii) three of 19 anti-I-Ak mAb; and iii) one A.TL-derived anti-I-As mAb. Competitive Id binding assays revealed that among the 14 IdX+ anti-Ia.7 mAb, one (81.B) was bound to a lesser extent by various rat anti-Id mAb, suggesting that heterogeneity probably exists in this antibody family. By contrast, two isologous (B10.S(7R)) anti-Id mAb to the IdX.Ia.7+ mAb 41.A displayed a specificity restricted to 41.A individual idiotopes (IdI). Rat anti-IdX.Ia.7 and mouse anti-41.A IdI mAb inhibited the binding of 125I-labeled mAb 41.A to CBA spleen cells. These two sets of mAb bound in a noncompetitive fashion to mAb 41.A-coated plates, indicating that their corresponding public or private idiotopes were spatially distinct. These data may have implications for in vivo manipulations of anti-Ia immune responses.

Animals↗