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Biomedical subjects

C Vincent

Publications and source records attributed to C Vincent.

At least 217 records · Page 12Linked to original sources
PubMed1990

Subclass distribution of IgG antibodies to the rat oesophagus stratum corneum (so-called anti-keratin antibodies) in rheumatoid arthritis.

Serum IgG, labelling the stratum corneum of the rat oesophagus epithelium, so-called anti-keratin antibodies (AKA) constitute the most specific marker for the diagnosis of rheumatoid arthritis. In this study, we investigated 31 IgG AKA-positive rheumatoid sera and 21 control sera from patients with non-rheumatoid inflammatory rheumatic diseases. The serum level of IgG1,2,3 and 4 was determined by radial immunodiffusion and the subclass distribution of IgG AKA by a three-step semi-quantitative immunofluorescence assay using standard monoclonal antibodies specific for each of the four human IgG subclasses. In the rheumatoid sera, the serum level of IgG1 was found to be significantly increased and the level of IgG2 significantly decreased with regard to the control sera, while the levels of IgG3 and 4 as well as total IgG were in the normal range. IgG1,2,3, and 4 AKA were detected in 27 (87%), 6 (19%), 4 (13%) and 11 (35%) of the 31 rheumatoid sera, respectively, and were found to be independent of the clinical and biological indices of the disease. In spite of inter-individual heterogeneity, two predominant profiles were distinguished: IgG1 (alone) and IgG(1 + 4), which together represented 18 sera (58%). The large predominance of IgG1 AKA and the quasi-absence of IgG2 AKA suggest that the recognized antigen may be partly comprised of protein. Moreover, the high frequency of occurrence of IgG4 AKA might result from chronic exposure to the eliciting antigen, which could be a genuine autoantigen since we demonstrated that it is also present in the stratum corneum of human epidermis.

Animals↗
PubMed1990

The hardening effect of dimethylsulphoxide on the mouse zona pellucida requires the presence of an oocyte and is associated with a reduction in the number of cortical granules present.

When mouse ovulated oocytes were exposed to 1.5 M-dimethylsulphoxide (DMSO) the resultant hardening of the zona pellucida was not a direct effect but required the presence of an oocyte. The hardening of the zona pellucida when zonae used were aged in vitro was also dependent upon the presence of the oocyte. Protocols of DMSO exposure that induce zona-hardening also caused depletion of the numbers of cortical granules underlying the oocyte surface, whereas protocols without effect on the zona did not reduce significantly the cortical granule count. It is proposed that the effects of DMSO may be mediated by a release of cortical granule contents.

Animals↗
PubMed1989

Limiting dilution cloning of B cells from patients with multiple myeloma: emergence of non-malignant B-cell lines.

Multiple myeloma (MM) is a B-cell malignancy characterized by the accumulation of slowly proliferating malignant plasma cells in the bone marrow (BM). Several reports have shown the existence of an abnormal B-cell compartment including proliferative idiotypic B cells (i.e., B cells bearing the same idiotypic determinants as the myeloma protein) in the BM and peripheral blood (PB) of patients with MM. In order to study whether this abnormal compartment can be grown in vitro, we cultured the PB and BM of 23 patients with MM using limiting dilution methods. Our purpose was to restrict the effect of suppressor cells and the possible overgrowth of the cultures by the more rapidly growing B cells, which occurs in bulk cultures. Spontaneously growing cells were obtained only from patients seropositive for the Epstein-Barr virus (EBV) and all the cultures were composed of B cells carrying the EBV genome. Thus, positive cultures were generated only in the presence of B cells latently infected with EBV in vivo. The mean frequency of these B cells (1 in 25,000 B cells) was as low in MM patients as in healthy donors. This low frequency indicated that malignant cells do not bear the EBV genome in vivo and that the in vivo regulation of the EBV infection is unaffected in patients with MM. No Ig-gene rearrangements, specific of the autologous myeloma cells, were found in the cell lines obtained from BM or PB. Thus, the putative malignant B cells or myeloma cells were not able to generate cell lines in vitro, either spontaneously or after endogenous infection with EBV.

Antibodies, Viral↗
PubMed1989

Charge heterogeneity of beta 2-microglobulin in lymphoid cells.

Extracts of blood lymphocytes, polymorphonuclear neutrophils and B, T or monocytic cell lines were analyzed by two-dimensional gel electrophoresis and immunoradiometric assay after electro-transfer to nitrocellulose sheets with radiolabelled polyclonal or monoclonal antibodies specific for beta 2-microglobulin. Four different forms of the molecule were identified with an apparent Mr of 12,000 and pI values of 5.7, 5.3 and lower. Lymphocyte activation by phytohemagglutinin and concanavalin A, or incubation with recombinant alpha 2b interferon, resulted in an increased beta 2-microglobulin cell content and release of the protein in supernatants with a predominant elevation of the more acidic minor forms. Recombinant interleukin-2 and recombinant gamma interferon increased the expression of the molecule without significant shift in the relative proportion of beta 2-microglobulin forms. Tumor necrosis factor alpha did not increase cell beta 2-microglobulin (beta 2-m) content and release and did not alter the relative distribution of the different forms of the molecule. Several mechanisms may be considered for the generation of beta 2-m microheterogeneity, including intracytoplasmic post-translational modifications such as proteolysis or modification of the amide groups of internal amino acids.

Biological Factors↗
PubMed1989

Chronic experimental autoimmune encephalomyelitis in the guinea pig. Presence of anti-M2 antibodies in central nervous system tissue and the possible role of M2 autoantigen in the induction of the disease.

Experimental autoimmune encephalomyelitis (EAE) can be transferred adoptively with T cells sensitized to the basic protein of myelin (BP). However, in the guinea pig, the chronic form of EAE has not been found to be inducible with BP alone, nor has it been adoptively transferred. An antibody response to the central nervous system (CNS) myelin autoantigens was looked for in serum and target CNS tissue in S13 guinea pigs with isologous CNS tissue-induced chronic EAE. Antibody activity was estimated by an immunoenzymatic technique and by autoradiography, using immunoprecipitated and electrophoresed relevant radiolabelled antigens. In serum, IgG antibody response to BP and M2 reached its maximum level 30 to 40 d after immunization and then declined progressively until it became undetectable. On the other hand, while anti-BP antibodies were seldom detected in CNS tissue acid extract, anti-M2 IgG antibodies were always present in CNS tissue of chronic EAE animals, and the amount of these antibodies were related to the severity of symptoms and lesions. No antibody response to proteolipid or to galactocerebroside was detected in serum or CNS tissue. BP-immunized controls showed no chronic EAE and no response to M2 in their serum or CNS tissue. Inasmuch as M2 has been shown to be a glycoprotein of CNS myelin, and anti-M2 antibodies to have a demyelinating property, the latter would be responsible for CNS tissue demyelination in chronic EAE. A shared role of BP and M2 in the induction of chronic EAE in the guinea pig is suggested.

Animals↗
PubMed1989

High diagnostic value in rheumatoid arthritis of antibodies to the stratum corneum of rat oesophagus epithelium, so-called 'antikeratin antibodies'.

Serum antibodies to the stratum corneum of rat oesophagus epithelium, so-called 'antikeratin antibodies', have been largely demonstrated in rheumatoid arthritis (RA). IgM and IgG antibodies to this epithelium were studied by semiquantitative immunofluorescence in 528 patients with perfectly characterised rheumatic diseases, including 178 with classical or definite RA. Histological analysis of IgG antibodies showed that only antibodies which produce a linear laminated pattern restricted to the stratum corneum (IgG antikeratin antibodies) are highly specific for RA; all the other labelling patterns are not disease specific. By a semiquantitative evaluation of the stratum corneum fluorescence intensity it was shown that the diagnostic value of IgG antikeratin antibodies closely depends on their titre and it was established in objective conditions that the sensitivity is 43.26% when the specificity reaches 99.14%. A high titre of IgG antikeratin antibodies was actually pathognomonic for RA. Both the histological and semi-quantitative analyses showed that IgM antibodies to rat oesophagus epithelium, though frequently detected, are of no diagnostic value, either for RA or for any other rheumatic disease that was studied. From a review of all the international reports on IgG antikeratin antibodies it was found that, to date, 4080 patients, including 1694 with RA, have been assayed for antikeratin antibodies by 11 different research groups. Analysis of all the results obtained under comparable technical conditions showed that IgG antikeratin antibodies constitute the most specific serological criterion for the diagnosis of RA. Furthermore, it was found that their incidence does not depend on disease duration: they are present in one third of rheumatoid factor negative patients with RA, and they seem to be related to disease severity or activity, or both. Their detection in the diagnosis of rheumatic diseases should become systematic.

Adolescent↗
PubMed1989

Solvent effects on cytoskeletal organization and in-vivo survival after freezing of rabbit oocytes.

NBD-phallacidin revealed a polymerized actin distribution in the cortical region of the rabbit egg and along junctional feet. Staining with anti-alpha-tubulin antibody showed that the microtubule distribution was restricted to the barrel-shaped spindle. After cryoprotective treatment in the presence of propanediol, cortical polymerized actin was no longer visible within the egg and along junctional feet but filamentous actin was still present after treatment with dimethylsulphoxide. However, exposure to dimethylsulphoxide or propanediol led to the appearance of microtubules in the cytoplasm and to a disassembly of the spindle often associated with anomalies in chromosome position. Cytoplasmic microtubules formed by the action of propanediol were still present after freezing, thawing, and removal of the cryoprotectant, but after recovery of eggs in culture, they disappeared and barrel-shaped spindles were able to reform. When the effect of propanediol addition on in-vivo fertilization and development of frozen oocytes was examined, 39% (79/200) of frozen oocytes were fertilized and 9% (9/105) developed to normal fetuses, compared to 81% (38/47) and 32% (12/38) respectively for unfrozen control oocytes.

Actin Cytoskeleton↗
PubMed1989

Phenotypic analysis of human myeloma cell lines.

Multiple myeloma (MM) is a B-cell malignancy characterized by the accumulation, primarily in bone marrow, of a clone of plasma cells. The nature of the stem cells feeding the tumoral compartment is still unknown. To investigate this special point, we have studied the phenotypes of nine well-known human myeloma cell lines (HMCLs) and compared them with those of normal lymphoblastoid cell lines (LCLs). Twenty-four clusters of differentiation involved in B lymphopoiesis were investigated using a panel of 65 monoclonal antibodies (MoAbs). For each cluster, the percentage of positive cells and the antigen density were determined, giving rise to a "quantitative phenotype". We thus classified the HMCLs into two different groups: those with cytoplasmic mu chains (c mu+) and those without (c mu-). In the first (c mu+) group, comprising seven cell lines, the HMCLs had a phenotype of pre-B/B cells close to that of Burkitt's lymphoma cell lines. They expressed low densities of surface mu chains, without detectable cytoplasmic or surface light chains. Three of them were infected with the Epstein Barr virus (EBV). These c mu+ HMCLs bore most of the B-cell antigens except CD23. They expressed the CALLA antigen (CD10) and lacked the plasma-cell antigen PCA1. In contrast, LCLs expressed surface light chains, high densities of CD23, low densities of PCA1 antigen, and no CD10 antigen. The c mu- HMCLs had a plasma-cell phenotype, lacking most of the B-cell antigens and expressing high densities of PCA1 antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Differentiation, B-Lymphocyte↗
PubMed1989

[Keratinocyte-fibroblast interactions: I. Production by the keratinocytes of soluble factors stimulating the proliferation of normal human skin fibroblasts].

Epidermal cells produce IL-1 and contra IL-1 which respectively stimulate and decrease fibroblast proliferation. In order to get better insight into the nature of keratinocyte-fibroblast interactions, we have analyzed the effect of soluble factors produced by unstimulated normal human keratinocytes and keratinocyte cell lines on the proliferation of normal human dermal fibroblasts. The results were compared to these obtained with human recombinant IL-1 and IL-2. We observed that: 1) normal keratinocytes (monolayers or stratified) released in the culture medium a factor stimulating fibroblast proliferation by 45 to 160%; 2) supernatants of unstimulated PAM 212 keratinocyte cell line also contained the stimulatory activity; 3) addition of IL-1 beta to the culture medium at concentration ranging from 0.1 to 1.000 U/ml induced a dose-dependent increase in fibroblast proliferation, whereas IL-2 was ineffective; 4) gel filtration analysis (ACA 54) of serum-free supernatant showed that the activity could be eluted from 3 peaks (Mw ranging from 10 to 20 kD). The present data show that unstimulated normal human keratinocytes produce soluble factor(s) (maybe related to IL-1) which stimulate human dermal fibroblast proliferation and which could be of major importance in the modulation of fibroblast metabolism, in vivo.

Adult↗
PubMed1989

Spontaneous expression of a low affinity Fc receptor for IgA (Fc alpha R) on human B cell lines.

Expression of receptors for IgA (Fc alpha Rs) was investigated on a panel of 35 human B cell lines by labelling with human secretory IgA (0.5 mg/ml) and flow cytometry analysis after staining with fluoresceinated goat anti-human secretory component and/or anti-alpha chain F(ab')2 fragments. Receptors for IgA could be demonstrated on one out of nine Burkitt's lymphoma cell lines, three out of five myeloma cell lines and five out of 21 lymphoblastoid cell lines. The percentage of Fc alpha R-positive cells within the same B cell line varied upon repeated examination. Human dimeric IgA1 lambda myeloma protein revealed the same number of IgA receptor positive cells as did secretory IgA, whereas monomeric IgA did not bind to Fc alpha R. Detection of Fc alpha R was not inhibited when the tests were carried out in the presence of human dimeric IgG, IgM, asialo-orosomucoid, and secretory component but it was abrogated by pre-treatment of the cells with trypsin. The binding characteristics of Fc alpha Rs were studied on the myeloma cell line Esteve, using 125I-labelled human dimeric IgA and secretory IgA. The binding was dose-dependent with rapid kinetics and specific inhibition by unlabelled secretory IgA. Scatchard plot analysis resulted in an equilibrium constant K ranging from 3.2 to 4.7 x 10(6) M/l. No correlation was observed between Fc alpha R expression and differentiation stage, monoclonality, polyclonality of the cell lines, or Ig class produced by the B cells.

Antibody Affinity↗
PubMed1988

The binding of beta-2-microglobulin to renal brush-border membrane: affinity measurement, inhibition by serum albumin.

In the kidney, filtered proteins are rapidly reabsorbed so that the final excretion is less than 0.1% of the filtered amount for low molecular weight proteins such as beta 2-microglobulin and a few percent for albumin. In order to investigate the affinity of proteins for luminal membranes, rat renal brush-border membranes were incubated with 125I-labelled human beta 2-microglobulin and the initial binding rate determined by the filtration method. Scatchard plot analysis of binding rate revealed two types of binding sites: one with Km = 0.25.10(-6) M and Vmax = 0.1 nmol/min per mg protein and another with Km = 1.10(-5) M and Vmax = 1.3 nmol/min per mg protein. The lower affinity type is likely to represent non-specific binding the physiological role of which is to be discussed. The higher affinity sites seem to play the major role in binding rate. beta 2-Microglobulin initial binding is reversible, and inhibited by bovine serum albumin. Comparison of the time course of bound beta 2-microglobulin removal by unlabelled beta 2-microglobulin and by albumin suggests that these two proteins have a different internalization mechanism.

Alpha-Globulins↗
PubMed1988

Sandwich-type ELISA for free and bound secretory component in human biological fluids.

Three sandwich-type enzyme-linked immunosorbent assays (ELISA) are described for the measurement of free secretory component (SC) and SC bound to IgA (S-IgA) or IgM (S-IgM). These assays do not require preliminary fractionation of the biological fluids to be tested. The specificity of the assays is achieved with monoclonal antibodies specific for free SC (855 SC) and for SC bound to IgA or IgM (8545 SA). The amount of the three SC molecules in various biological fluids is reported. We demonstrate the presence of low levels of free SC in most of these fluids, including normal serum. Moreover our results suggest that S-IgM in serum may result from a non-covalent association between serum IgM and free SC.

Adult↗
PubMed1988

High serum levels of secretory component in hepatocellular carcinoma.

PURPOSE: Elevated levels of secretory IgA (S-IgA) have been detected in serum samples from patients with liver diseases and neoplasia with liver metastasis. We undertook the current study in order to determine the concentrations of different forms of free secretory component (SC) in sera from patients with hepatocellular carcinoma. MATERIALS AND METHODS: The concentrations of SC, S-IgA, and secretory IgM (S-IgM) were quantified in the sera of 100 patients with hepatocellular carcinoma, and in 77 matched healthy control subjects by using an enzyme-linked immunosorbent assay. RESULTS: Free SC serum levels exceeded the upper limits of control values in 82 percent of patients with hepatocellular carcinoma, S-IgA levels in 88 percent of them, and S-IgM levels in 32 percent. Free SC levels were positively correlated with S-IgA and S-IgM levels. They were weakly correlated with gamma-glutamyl transpeptidase activity, but not with alpha-fetoprotein, beta 2-microglobulin, albumin, or IgA serum concentrations, nor with alkaline phosphatase activity. CONCLUSION: The data clearly demonstrate the elevation of serum free SC concentrations as a novel biologic alteration in hepatocellular carcinoma since free SC levels appear to be correlated neither with tumor markers (alpha-fetoprotein, beta 2-microglobulin) nor with biliary obstruction.

Adult↗
PubMed1988

Estrogen and progesterone receptors in some human myeloma cell lines and murine hybridomas.

The control of immune responses by sex hormones is well documented but the effect of sex hormones on lymphoid cell subsets is poorly understood. We have investigated the expression of receptors for androgens (AR), estradiol (ER) and progesterone (PR) by human cell lines of the B lymphocyte lineage and by murine myeloma or hybridomas. AR, ER and PR were determined by cytosol and nuclear binding assays. Eleven human lymphoblastoid cell lines obtained by in vitro infection of blood or tonsil B cells with Epstein-Barr Virus (EBV) B95, did not express AR or ER. Similarly, 10 Burkitt's lymphoma cell lines were AR, ER and PR negative with the exception of the pre-B RAJI cells which bear AR. Among 13 cell lines derived from patients with multiple myeloma none expressed AR but five were found to bear ER (20-164 fmol/mg DNA or 5-10 fmol/mg protein). Four of the latter group also bear PR (86-450 fmol/mg DNA). Two mouse hybridomas out of seven tested were ER and PR positive. The MOPC 315 myeloma expressed ER but not PR. The possible functional role of these sex hormone binding sites in cell proliferation and immunoglobulin secretion deserves further investigation.

Animals↗
PubMed1988

Intestinal secretory antibody response induced by an oral cholera vaccine in human volunteers.

The ability is reported of a new oral cholera vaccine composed of Vibrio cholerae antigenic fractions to induce a serum and mucosal antibody response after three oral administrations of microgranules to 18 French volunteers according to different protocols of immunization. Specific antibodies were detected in the three different fluids studied (saliva, jejunal fluid, serum) in one third of volunteers before vaccination. An increase of specific IgA antibody level was observed in jejunal fluids of most volunteers after oral vaccination. An augmentation of specific antibodies against vaccine antigenic components was also observed in serum and in saliva after vaccination but in fewer volunteers.

Administration, Oral↗