PubMed Health⌕ Search

Biomedical subjects

P Aucouturier

Publications and source records attributed to P Aucouturier.

At least 19 recordsLinked to original sources
PubMed1992

Complementary DNA sequence of human amyloidogenic immunoglobulin light-chain precursors.

The primary structure of three amyloid precursor light chains was deduced from the sequence of complementary DNA (cDNA) from bone marrow cells from patients affected with classical lambda (patient Air) or kappa (patient Arn) amyloidosis and from a patient (Aub) in whom lambda amyloid deposits were unusual by their perimembranous location in the kidney glomerulus. All three RNAs were of normal size, as estimated by Northern blotting, and encoded normal-sized light chains. The deduced light-chain sequence from patient Arn was related to the V kappa 1 subgroup, and included ten residues that had not been previously reported at these positions, only one of which (Leu-21) was located in a beta-sheet (4-2). The unusual presence of Asn-70 determined a potential N-glycosylation site. The sequence of the light chain from patient Air belonged to the V lambda 1 subgroup, and included three unusually located amino acid residues, one of which had already been reported in an amyloidogenic lambda-chain. The sequence of the light chain from patient Aub was related to the V lambda 3 subgroup, and contained five amino acid residues that had not previously been described at the corresponding positions; two of them (His-36 and Ser-77) were located in beta-sheets (3-1 and 4-3 respectively). This sequence was also peculiar because of the presence of numerous acidic residues in the complementarity-determining regions. Such unusual primary structures might be responsible for the amyloidogenic properties of these light-chain precursors.

Amino Acid Sequence↗
PubMed1992

Ganglioside GD1b is the target antigen for a biclonal IgM in a case of sensory-motor axonal polyneuropathy: involvement of N-acetylneuraminic acid in the epitope.

We report on a 54-year-old man with a sensory-motor polyneuropathy associated with a biclonal IgM-kappa gammopathy, which reacted with the ganglioside GD1b. Examination of nerve biopsy specimens showed some reduction in the density of myelinated fibers and axonal degeneration with a loss of large fibers and a relative increase in the density of small fibers. Immunodetection on thin-layer chromatography of the glycolipid antigens showed strong reactivity of the patient's serum IgM-kappa with GD1b ganglioside and weak binding to GD1a. biclonal IgM antibodies did not react with GM1, asialo-GM1, GT1b, GD2, or GD3. Indirect immunofluorescence staining showed binding of IgM-kappa mainly in a crescent-like pattern on the internal side of myelin sheaths, which could correspond either to an enlarged periaxonal (adaxonal) space or to the internal mesaxon or to both. The immunostaining was abolished after absorption of the serum with GD1b.

Antigens↗
PubMed1992

Methodological pitfalls in serum IgG2 level measurements by immunoenzymatic assays with monoclonal antibodies.

Four anti-IgG2 monoclonal antibodies (Mabs) were evaluated for their reactivity with purified myeloma IgG2 of different light chain types and Gm allotypes in three distinct immunoenzymatic assays (ELISA). The reactivity of three Mabs with solid-phase antigens was similar whereas an anti-Fab antibody (clone HP 6114) predominantly bound IgG2 kappa. In competitive and immunometric (sandwich type) assays, the binding of the two anti-IgG2 Mabs (HP 6014 and HP 6114) reacting with epitopes located on the Fab fragment was strongly influenced by the light chain type of IgG2 and by other factors (probably including differences in the variable regions); the Mab HP 6114 reacted virtually only with IgG2 kappa whereas the Mab HP 6014 displayed a much stronger affinity for IgG2 lambda than for IgG2 kappa; for both anti-Fab Mabs, important differences were found in their binding to individual IgG2 proteins. In addition, the Mab HP 6014 seemed to show a slightly better affinity for IgG2 bearing the Gm(23) allotype. These results urge much caution in IgG2 level measurement, especially with commercial kits, most of which use the Mab 6014 as the single anti-IgG2 reagent.

Antibodies, Anti-Idiotypic↗
PubMed1992

Isotypic and allotypic analysis with monoclonal antibodies and jacalin of 309 serum monoclonal IgA from French and Japanese myeloma patients.

The subclass and allotype distribution of serum monoclonal IgA from myeloma patients was determined by ELISA with monoclonal antibodies in two French and one Japanese laboratory. In addition, the French sera were tested for their reactivity with the lectin jacalin. No significant difference in the isotypic distribution between French and Japanese series could be demonstrated: kappa/lambda ratios were 0.99 and 1.17, and the IgA1 subclass accounted for 93.9% and 91% of cases in the French and Japanese studies, respectively. Five out of 7 myeloma IgA2 from Japan and only one of the 12 IgA2 from France belonged to the A2m(2) allotype (P less than 0.01). All 219 IgA1 tested reacted with jacalin by immunoelectrophoresis (IEP), although with variable intensities. Among IgA2 proteins, only one (of the A2m(1) allotype) yielded a precipitating line with jacalin by IEP. Molecular analysis demonstrated that this protein was an IgA1-IgA2 hybrid bearing most of the A2m(1) epitopes.

Antibodies, Monoclonal↗
PubMed1992

Primary structure of a monoclonal kappa chain in myeloma with light chain deposition disease.

Previous data suggest that structural abnormalities of immunoglobulin light chains may be responsible for non-amyloid light chain deposition disease (LCDD). We report on the complete primary sequence deduced from complementary (c)DNA analysis of a normal-sized kappa chain in a case of myeloma-associated LCDD. The patient's urine contained a kappa type Bence-Jones protein made of monomers and dimers of an unglycosylated kappa chain. The bone marrow myeloma cells contained intracellular kappa and gamma chains by immunofluorescence. Biosynthesis experiments showed the production of normal-sized gamma chains and of kappa chains with the same apparent molecular mass (Mr) in SDS gels as the urinary kappa chain (26,000-27,000). These kappa chains were secreted as assembled IgG molecules and as a large excess of free monomers and dimers. The complete sequence of two identical cDNA clones derived from a normal-sized kappa messenger RNA indicated that this kappa chain belonged to the rare V kappa IV subgroup. The kappa mRNA had an overall normal structure made up of the V kappa IV sequence rearranged to J kappa 1 and followed by a normal constant exon of the Km(3) allotype. The variable region differed from the V kappa IV-J kappa 1 germline sequence by 17 amino acid substitutions. The peculiar sequence of the variable region of this kappa chain of a rare subgroup might relate to its tissue deposition.

Aged↗
PubMed1991

A filter affinity transfer method for the analysis of rheumatoid factors.

Transfer of serum proteins separated by thin layer agarose electrophoresis onto nitrocellulose sheets precoated with purified human polyclonal IgG followed by revelation with enzyme-coupled anti-mu or anti-alpha antisera resulted in the specific detection of rheumatoid factors (RF) belonging to the IgM or IgA classes. Mono- or polyclonality of such RF can be evaluated from the patterns of the blots (sharp bands). In addition, their light chain type can be determined using affinity filters coated with a gamma heavy chain disease protein or with IgG Fc fragments. This simple and rapid procedure allows an easy characterization of monoclonal RF, even if they are present in minute amount amongst polyclonal RF as in certain sera from rheumatoid arthritis patients.

Antibodies, Monoclonal↗
PubMed1991

The subclass distribution of IgG autoantibodies in cicatricial pemphigoid and epidermolysis bullosa acquisita.

To study the subclass distribution of autoantibodies and their complement-fixing capacity in cicatricial pemphigoid (CP) and epidermolysis bullosa acquisita (EBA) we studied the sera from 23 patients by both indirect immunofluorescence (IIF) on 4-microns cryostat sections of normal human skin and immunoblotting of epidermal or dermal extracts. Monoclonal antibodies of strict specificity for human IgG subclasses were used. Sera from 20 patients with BP served as controls. In addition, total IgG subclass levels were determined by indirect competitive ELISA in all sera. Complement binding capacity was studied by IIF using antibodies to C3 after incubation of skin section with autoantibodies and source of fresh complement. CP autoantibodies reacting with the 230-240 kD and/or the 180-kD epidermal bands showed an IgG4/IgG1 subclass restriction, with a predominance of IgG4 in 10 cases, of IgG1 in four. In BP sera, IgG4 and IgG1 autoantibodies were detected with a similar frequency (100% and 83%, respectively). In EBA sera, autoantibodies reacting with the 290 kD and 145 kD dermal bands also showed an IgG1/IgG4 restriction. Concordant results were obtained by IIF. However, the IIF method had a lower sensitivity for the detection of IgG4 CP antibodies and IgG1 EBA antibodies than immunoblotting. Finally, when CP antibodies were analyzed for their complement-binding activity, it was found that sera containing IgG4 autoantibodies alone never fixed complement whereas all complement-fixing CP sera had IgG1 autoantibodies, suggesting that only this subclass of antibodies is capable of fixing complement.

Aged↗
PubMed1991

Changes in serum immunoglobulin patterns in adults with common variable immunodeficiency.

Striking variations of serum immunoglobulin class and IgG subclass levels were observed in five patients with common variable immunodeficiency. They occurred mainly in untreated patients or, in those patients who received substitutive therapy, could not be merely due to replacement. They result in major changes in the immunoglobulin deficiency patterns, such as a shift from profound hypoimmunoglobulinaemia to IgA/IgG2/IgG4 deficiency or to isolated IgG2 deficiency. These findings have practical implications for the diagnosis and management of patients with primary humoral immunodeficiency.

Adult↗
PubMed1991

Structure of a monoclonal kappa chain of the V kappa IV subgroup in the kidney and plasma cells in light chain deposition disease.

That structural abnormalities may be responsible for nonamyloid immunoglobulin (Ig) light chain deposition disease (LCDD) is suggested by previous results of Ig biosynthesis studies, but this hypothesis was not documented at the molecular level. We report on the first complete primary sequence deduced from cDNA analysis of a kappa light chain responsible for LCDD associated with an apparently nonsecretory myeloma. Bone marrow myeloma cells contained intracellular kappa chains and no heavy chains by immunofluorescence. Kidney biopsy showed typical nonamyloid PAS-positive kappa chain deposits. SDS-PAGE analysis of material extracted from a kidney biopsy specimen and of Ig produced by the myeloma cells revealed kappa chains of abnormally high apparent molecular mass (30,000). Comparison of the NH2-terminal aminoacid sequence of the kappa chain deposited in the kidney and of the complete sequence of several identical kappa cDNA clones from bone marrow cells showed the identity of the tissue deposited and plasma cell kappa chain. The kappa mRNA had an overall normal structure and corresponded to the V kappa IV gene rearranged to J kappa 1 and followed by a normal constant exon of the Km(3) allotype. The variable sequence differed from the V kappa IV germline gene by nine point mutations, including an Asp----Asn substitution at position +70 resulting in a potential N-glycosylation site. In vitro biosynthesis experiments and treatment with N-glycosidase provided evidence for the intracellular glycosylation of the monoclonal kappa chain. The peculiar sequence and the glycosylation of a kappa chain of the rare V kappa IV subgroup might be responsible for structural abnormalities leading to tissue deposition.

Amino Acid Sequence↗
PubMed1990

Immunoglobulin light chain transcripts with altered V regions in Burkitt's lymphoma cell lines producing short mu chains.

The Burkitt lymphoma cell lines Ly91, Ly47 and Ly66 produce short mu chains in the absence of associated light (L) chains. mu mRNA lack two-thirds of the variable (V) region due to an alternate splicing event that takes place within V genes. L chain genes were found to be rearranged in these lines and to lead to transcripts with altered V regions. Although these abnormal transcripts displayed specific abnormalities in each cell line, they shared some features, including large deletions involving the V-J junction. In one cell line, L chain transcripts made up of either V kappa I subgroup gene J kappa 3 or V kappa IV gene-J kappa 4 recombination products bore a similar alteration: the donor splice site of the rearranged J kappa segment was modified, leading to the alternate use of the donor site of either the leader peptide exon or the next 3' unrearranged J kappa segment.

Base Sequence↗
PubMed1990

Immunoblot analysis of IgG subclasses of circulating antibodies in bullous pemphigoid.

Sera from 20 patients with bullous pemphigoid (BP) were analyzed for the subclass distribution of IgG autoantibodies by Western immunoblotting of normal human heat-separated epidermal extracts. Strips were sequentially probed with patient sera, monoclonal antibodies (Mab) anti-human IgG1-4, and a labeled anti-mouse Ig. The relative dilutions of each subclass-specific Mab were determined in dot immunobinding experiments in order to give uniform reactivity to the corresponding human IgG subclass. Circulating BP autoantibodies reacting with the major BP antigen of 220 kDa and/or a 165-kDa band showed a stricking predominance of IgG4. Overall, IgG4 was the major subclass reactive with the 220-kDa band, whereas, in addition to IgG4, IgG1 and IgG2 were frequently represented in the response to the 165-kDa band. Complement fixation of circulating BP antibodies was studied by complement indirect immunofluorescence using human serum as source of complement and FITC goat anti-human C3, C1q, and C4, on normal human skin substrate. When circulating BP antibodies contained IgG1 or IgG2 in addition to IgG4, they fixed C3 and, in some cases, C1q and C4, suggesting complement activation by either the classical or the alternate pathway.

Blotting, Western↗
PubMed1990

Structural and functional similarities of breadfruit seed lectin and jacalin.

Aquous extracts from seeds of Artocarpus altilis (breadfruit) and Artocarpus heterophyllus (jackfruit) were compared by polyacrylamide gel electrophoresis. Two bands of the same size (12 and 15 kD) as the jacalin subunits were the major components in breadfruit seed extract. They strongly reacted with anti-jacalin antibodies by western blotting. The breadfruit lectin displayed the same IgAl and IgD precipitation specificity as jacalin in gel double diffusion experiments. It also stimulated in vitro proliferation of human peripheral blood mononuclear cells. These results suggest that lectins from both species of Artocarpus are very similar.

Cell Division↗
PubMed1990

Jacalin: a lectin mitogenic for human CD4 T lymphocytes.

The major protein component of seeds from jackfruit is the lectin jacalin. Jackfruit crude extracts are known to stimulate human lymphocytes, but the mitogenic properties of purified jacalin have not been studied in detail so far. Study of the proliferative response of cell populations from normal human peripheral blood to purified jacalin showed it to be mitogenic through an interaction with lymphocytes by its lectin-binding site, as shown by inhibition by IgA. Jacalin failed to stimulate B cells to proliferate and to undergo plasma cell maturation. It induced a proliferation of CD4 (and not CD8) lymphocytes, as shown by phenotypic analysis of cells recovered after culture and by studies of the response of isolated T cell subpopulations. The proliferative response to jacalin was autologous monocyte-dependent. The kinetics of jacalin-induced DNA synthesis, expression of CD25 and interleukin-2 secretion was shifted by comparison with that induced by phytohaemagglutinin. The reason for the restricted responsiveness of CD4 T cells is presently unclear; jacalin bound to all blood cells and did not significantly co-cap with CD1, CD2, CD3, CD4, CD8 and CD38, and jacalin response was neither enhanced nor inhibited by antibodies to these surface antigens.

Adult↗
PubMed1990

Haemophilus influenzae type b cellulitis of the lower extremity in a non-immunocompromised elderly patient.

An 83-year-old non-immunocompromised man who developed Haemophilus influenzae cellulitis on his lower left leg is described. H. influenzae type b was isolated by conventional bacteriological cultures from one blood culture and from a cutaneous blister fluid aspirate, and identified within the dermis by immunofluorescence on a punch biopsy of lesional skin. Evolution was characterized by a slow healing during appropriate systemic antibiotherapy, and absence of any significant increase in antibodies to the capsular polysaccharide of H. influenzae type b.

Aged↗
PubMed1989

Functional brain asymmetry and murine systemic lupus erythematosus.

The role of brain lateralization in antibody production was studied in a murine systemic lupus erythematosus model. Male and female New Zealand black mice that spontaneously produce pathogenic auto-antibodies directed against red blood cells and DNA, were divided into right- and left-handers using a paw preference test, and anti-erythrocyte and anti-DNA antibody production was repeatedly determined. In females, antibodies against erythrocytes and double-stranded DNA appeared earlier in left-handers. These results provide the first evidence of an association between a functional brain asymmetry and auto-antibody production and suggest the involvement of the central nervous system in the pathogenesis of autoimmune processes.

Aging↗