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J C Weber

Publications and source records attributed to J C Weber.

At least 55 records · Page 3Linked to original sources
PubMed1994

Structure-function studies on a polyreactive (natural) autoantibody. Polyreactivity is dependent on somatically generated sequences in the third complementarity-determining region of the antibody heavy chain.

SMI is a previously characterized IgM kappa polyreactive (natural) autoantibody. The variable regions of the heavy and light chains of SMI are respectively encoded by a nonmutated VH1 gene, designated 51p1, and a conserved nonmutated V kappa gene, designated Humkv325. These V genes seem to be over-represented in the autoimmune and fetal B cell repertoires, and to be frequently expressed in malignant B cells during certain lymphoid proliferations such as chronic lymphocytic leukemia. Polyreactive natural autoantibodies are thought to rely mainly on the use of such V genes in germ-line configuration. However, this model underestimates the contribution of the somatically generated heavy chain third complementarity-determining region (HCDR3) to autoantibody specificity. We used oligonucleotide site-directed mutagenesis to permute the sequence of the SMI-HCDR3 to generate a family of mutant proteins, each of which differed from the original SMI-IgM kappa by one amino acid residue. This allowed us to examine the relative contribution of selected amino acid residues in this region to the binding affinity of SMI against a panel of self-Ags. We found that a single amino acid substitution within the HCDR3 could dramatically alter the specificity of this autoantibody. Some substitutions abrogated the reactivity with all the tested Ags, whereas others changed the affinity or spectrum of reactivity for certain self-Ags. These results demonstrate that the autoantibody-binding activity of these conserved autoantibody-associated germ-line V genes is dependent upon heavy chain junctional sequences that are generated somatically during Ig gene rearrangement.

Animals↗
PubMed1994

[Granulomatous mastitis, erythema nodosa and oligoarthritis. Apropos of a case].

The authors report a case of granulomatous mastitis associated with erythema nodosum and oligoarthritis. The skin and joint symptoms improved with potassium iodide. The breast lesion clinically simulated a tumor of high malignant grade. Granulomatous mastitis is a benign and rare disease. Its interest lies in the possible association with systemic manifestations and in its steroid responsiveness. This condition has been recently described as a distinct entity. When associated with systemic manifestations, sarcoidosis should be considered.

Adult↗
PubMed1994

Evidence that the V kappa III gene usage is nonstochastic in both adult and newborn peripheral B cells and that peripheral CD5+ adult B cells are oligoclonal.

There is evidence that in certain situations the expressed antibody repertoire is dominated by small subsets of V gene segments. They include fetal, CD5+, and autoantibody-forming B cells as well as low grade B cell malignancies. For instance, inside the V kappa III family of approximately 10 members, only 3 (humkv325, 328, and Vg) are used recurrently for autoantibody production. However, the significance of this recurrence is difficult to interpret without a clear vision of the actual repertoire in normal subjects. To address this, we have sequenced and compared two sets of rearranged V kappa III genes generated by cDNA PCR amplification from a normal newborn, a normal adult, and from CD5+ B cells of the same adult donor. The results show that: (a) only four V kappa III gene segments are used by neonatal and total adult B cells (humkv325, humkv328, Vg, and kv305), humkv325 being overexpressed in both repertoires; (b) there is no significant difference in terms of V kappa III gene usage between the adult and newborn repertoires; (c) regarding the junction regions, there is a favored use of the most 5' JK gene segments (Jk1-Jk2); approximately 20% of the newborn and adult junction sequences was characterized by one or two additional codons, most probably resulting from a nontemplate addition of nucleotides; (d) adult clones, in contrast to most newborn clones, show sequence divergences from prototype sequences with patterns which suggest antigen-driven diversity; (e) regarding the adult CD5+ B cell library, it is most probable that the 78 clones analyzed derived from no more than nine different VK-JK rearrangements. Humkv325 is used by at least six of them, and most of the expressed V genes were in exact or very near germline configuration. Collectively these results suggest that the expressed antibody V kappa III repertoire in the adult represents only a fraction of the potential genetic information and that it resembles the preimmune repertoire of the neonate. The data, which also suggest that the adult peripheral blood CD5+ B cell population may be dominated by a small number of B cell clones, are discussed with regards to the V kappa III usage in pathological situations.

Adult↗
PubMed1994

Molecular analysis of rearranged VH genes during B cell chronic lymphocytic leukemia: intraclonal stability is frequent but not constant.

Several genetic mechanisms have been shown to diversify the expressed antibody repertoire of committed B lymphocytes. These include V gene replacement, ongoing gene rearrangement and somatic hypermutation. These mechanisms may be operational at discrete points in the B cell differentiation pathway and generate idiotype diversity in various malignant B cell tumors. In particular, V region mutations have been established as a major mechanism of tumor escape from anti-idiotype immunotherapy in some lymphoma. On the other hand, previous studies on a few selected cases have shown that this mutation process does not affect the B cell clone during chronic lymphocytic leukemia. However, to what extent this intraclonal stability is a general phenomenon during B cell CLL is not clear. Therefore, we randomly selected 6 patients suffering from classical B cell CLL (sIgM (+), CD5 (+), CD19 (+)) at different stages of the disease and analysed the intraclonal variability of the expressed variable region of the heavy chain (VH). After PCR amplification of the cDNA corresponding to the rearranged VDJ regions, the products were cloned and sequenced. In five cases, multiple clone analysis did not show any intraclonal variability whatever the stage of the disease. Furthermore, in a single case, this intraclonal stability was confirmed during a three year period of time when the disease progressed. The sixth case behaved differently since we found multiple nucleotide substitutions, apparently accumulating as the malignant clone expanded. Besides the theoretical difficulties that these changes can induce during immunotherapy, two findings merit further discussion: 1) the distribution of the ongoing mutations affecting the VH region was not suggestive of an antigen driven selection, 2) this intraclonal variability was specific for the VH region, since the VL region showed no intraclonal variation.

Aged↗
PubMed1993

Association between gastrointestinal tract carriage of Candida, blood group O, and nonsecretion of blood group antigens in patients with peptic ulcer.

Of 112 patients with peptic ulcer disease examined for oral carriage of Candida, 66 (59%) were carriers. Candida carriage was associated with blood group O (P < 0.05) and, independently, with nonsecretion of blood group antigens (P < 0.01). For each subject, the presence or absence of yeasts was found to be a constant characteristic, and only among patients positive for Candida was blood group O or nonsecretion more frequent than expected in the general population. The quantity of yeasts isolated was significantly greater in patients than in normal subjects (P < 0.002), as was the frequency of carriage in the patient population (59% vs 32%). This increase was not associated with treatment with H2-receptor antagonists. The results of paired oral and gastroduodenal aspirate cultures suggested that identifying Candida in the oral cavity was a good indicator of the presence of yeasts elsewhere in the gastrointestinal tract. Mechanisms whereby overgrowth of Candida in the upper gastrointestinal tract might contribute to the inflammatory background of peptic ulcer disease are discussed.

ABO Blood-Group System↗
PubMed1993

Analysis of the V kappa III variable regions of polyclonal rheumatoid factors arising during Epstein Barr virus induced infectious mononucleosis.

The mechanisms that govern autoantibody production are still under debate. In particular, auto-antibodies can appear as a consequence of a polyclonal activation of B cells or as a consequence of an antigen driven B cell expansion. The molecular analysis of the variable regions of auto-antibodies arising during different clinical situations can help to understand the origin of auto-antibodies. We recently described the main light chain variable regions of polyclonal rheumatoid factors occurring during rheumatoid arthritis and suggested that the mutation pattern of these regions could reflect an antigen driven process. Using the same approach, we now report the molecular analysis of the same light chain variable region containing a VKIII segment of rheumatoid factors originating from a polyclonal activation of B cells during an in vivo Epstein-Barr virus infection, infectious mononucleosis. The cDNA derived from rheumatoid factor synthetizing cells were amplified by two sets of polymerase chain reaction. The amplified products were cloned in M13mp19 phages and sequenced. The nucleotide analysis of the VKIII containing VK regions shows that: 1) the rheumatoid factor activity is associated with the 3 VKIII genes (Kv 325, Kv 328 and Vg) already known to encode for monoclonal and polyclonal rheumatoid factors, 2) there is a preferential use of Kv 328 and Vg, each one of these genes being poorly mutated, 3) the CDR mutation rates of these genes is no higher than the framework mutation rates, 4) there is a restriction of the JK usage; Kv 328 derived gene segments rearrange exclusively with JK1, Vg preferentially rearranges with JK1 and JK4. These results mainly suggest that naturally occurring polyclonal activation of autoreactive B cells produces poorly mutated autoantibodies.

Adult↗
PubMed1992

[Rheumatoid factors].

Rheumatoid factors (RF), which are auto-antibodies recognising the Fc fragment of IgGs, are the commonest auto-antibodies in man. They are present in polyclonal form in a large number of auto-immune disorders as well as in certain inflammatory states. In monoclonal form, they are frequently the product of "mature" malignant (chiefly Waldenström's macroglobulinemia and chronic lymphoid leukemia) and allegedly benign (such as cryoglobulinemias) lymphoid proliferations. In addition, RF account for a significant part of the normal antibody repertory, notably during the fetal and neonatal periods, suggesting that they may play an important role in the development and regulation of the immune system. As a result, RF are an excellent model for the analysis of auto-immunity in man. Thus many indirect (analysis of antigens recognised and of idiotopes carried) and, more recently, direct (protein or nucleotide sequencing of their various regions) studies have now provided the following conclusions. RF are coded by a very limited repertory of V genes. These genes are present in the normal genome and appear to be highly preserved in the human species. They are used with very few somatic mutations by monoclonal B proliferations (which opens up valuable therapeutic possibilities) as well as probably by RF producing B lymphocytes in normal individuals. In contrast, in the context of auto-immune disorders, these same genes have many somatic mutations suggesting maturation governed by the antigen and/or escape from idiotype control.

Autoimmune Diseases↗
PubMed1991

Cunninghamella bertholletiae: an uncommon agent of opportunistic fungal infection. Case report and review.

Cunninghamella bertholletiae is a fungus of the Zygomycetes class, Mucorales order. Only very few cases of disseminated infection have been reported. We observed a new case in a 19 years old man with severe aplastic anemia, due to pulmonary primoinfection and hematologic dissemination. This aplastic anemia failed to respond first to an antithymocyte globulin and steroid treatment and then to cyclosporine A. Deferoxamine was infused weekly to prevent iron overload. During a second antithymocyte globulin and steroid treatment, the patient developed bilateral pneumonia. Culture of the broncho-alveolar washing fluid established the diagnosis by isolation of C. bertholletiae. Despite amphotericin B and 5-fluorocytosine intravenous therapy, the patient died of disseminated infection six days after diagnosis, which was confirmed by necropsy. Underlying conditions, diagnosis and treatment are discussed, together with a review of the literature.

Adult↗
PubMed1990

Recognition of synthetic peptides of Sm-D autoantigen by lupus sera.

The reactivity of autoantibodies present in the serum of patients with systemic lupus erythematosus (SLE) was investigated by ELISA using seven overlapping synthetic peptides representing the entire sequence of the polypeptide D component of 'Sm antigen'. Of the 165 SLE sera tested, 59% were found to contain IgG antibodies able to bind to peptide 1-20, while 37% of the sera reacted with peptide 44-67. All sera reacting with peptide 44-67 also reacted with peptide 1-20. These two peptides were only seldom recognized by the sera of 187 patients with other rheumatic autoimmune diseases or by 53 sera of normal individuals. In a parallel study using sera that reacted with the D band in immunoblotting, most of the sera recognized peptides 44-67 (89%) and 1-20 (67%), while 33% of them reacted with peptide 97-119. The use of these synthetic peptides in ELISA may be of considerable help for detecting anti Sm autoantibodies.

Amino Acid Sequence↗
PubMed1989

X-ray crystallographic analysis of the structural distortions induced by substitution and annulation of the dodecahedrane nucleus.

Methyl dodecahedranecarboxylate, C22H22-O2, (4), Mr = 318.42, monoclinic, C2/c, a = 12.600 (2), b = 7.992 (4), c = 28.975 (7) A, beta = 101.79 (2) degrees, V = 2856 A3, Z = 8, Dx = 1.48 g cm-3, lambda(Mo K-alpha) = 0.71073 A, mu = 0.84 cm-1, F(000) = 1360, T = 294 K, R = 0.044 for 2109 unique reflections with Fo2 greater than 3 sigma(Fo2). 21-Phenylcyclopropadodecahedrane, C27H24, (5), Mr = 348.49, tetragonal, P4(2)/n, a = 17.528 (3), c = 10.752 (2) A, V = 3303 A3, Z = 8, Dx = 1.40 g cm-3, lambda(Mo K-alpha) = 0.71069 A, mu = 0.85 cm-1, F(000) = 1488, T = 295 K, R = 0.053 for the 1773 unique reflections with Fo2 greater than 1 sigma(Fo2). The molecular geometries of methoxycarbonyldodecahedrane (4) and 21-phenylcyclopropadodecahedrane (5) are compared to those of the parent C20H20 hydrocarbon (1) and its 1,16-dimethyl derivative (2). For both (2) and (4), the framework is modestly distorted by the substituents, the intracavity distance being more extended along the axis that contains the pendant group(s). Remarkably for (5), its cyclopropane ring has all C-C bonds and internal angles essentially equal, and those dodecahedrane bonds in the immediate vicinity of the ring fusion are extensively perturbed.

Molecular Structure↗
PubMed1988

Oral carriage of Candida albicans, ABO blood group and secretor status in healthy subjects.

ABO blood group and secretor status were determined in healthy subjects in relation to oral carriage of Candida albicans, using a mouthwash technique to identify carriers and non-carriers. Of 100 subjects studied, 32% carried Candida, the main species isolated being C. albicans (94% isolates). Carriage of C. albicans was significantly associated with blood group O (p less than 0.001) and independently, with non-secretion of blood group antigens (p less than 0.001), with the trend towards carriage being greatest in group O non-secretors. This suggests that in healthy subjects, blood group O and non-secretion of blood group antigens are separate and cumulative risk factors for oral carriage of C. albicans.

ABO Blood-Group System↗