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J Thonnard

Publications and source records attributed to J Thonnard.

12 recordsLinked to original sources
PubMed2001

High frequency of cytolytic T lymphocytes directed against a tumor-specific mutated antigen detectable with HLA tetramers in the blood of a lung carcinoma patient with long survival.

We have identified an antigen recognized by autologous CTL on the lung carcinoma cells of a patient who enjoyed a favorable clinical evolution, being alive 10 years after partial resection of the primary tumor. The antigenic peptide is presented by HLA-A2 molecules and encoded by a mutated sequence in the gene coding for malic enzyme, an essential enzyme that converts malate to pyruvate. In the tumor cell line derived from the patient, only the mutated malic enzyme allele is expressed, because of a loss of heterozygosity in the region of chromosome 6 that contains this locus. Tetramers of soluble HLA-A2 molecules loaded with the antigenic peptide stained approximately 0.4% of the patient's blood CD8 T cells. When these cells were stimulated in clonal conditions, 25% of them proliferated, and the resulting clones were lytic and specific for the mutated malic enzyme peptide. T-cell receptor analysis indicated that almost all of these antimalic CTLs shared the same receptor. Antimalic T cells were consistently found in blood samples collected from the patient between 1990 and 1999, at frequencies ranging from 0.1 to 0.4% of the CD8 cells. Their frequency appeared to double within 2 weeks after intradermal inoculation of lethally irradiated autologous tumor cells. These results indicate that nonmelanoma cancer patients may also have a high frequency of blood CTLs directed against a tumor-specific antigen.

Amino Acid Sequence↗
PubMed1999

Two antigens recognized by autologous cytolytic T lymphocytes on a melanoma result from a single point mutation in an essential housekeeping gene.

We have pursued our analysis of antigens recognized by autologous cytolytic T lymphocytes (CTLs) on the melanoma cells of patient LB33. This patient enjoys an unusually favorable evolution, which is associated with a strong and sustained antitumor CTL response. We reported previously the analysis of two melanoma cell lines, MEL.A and MEL.B, which were derived from metastases removed from the patient at 5 years' distance. Autologous CTL clones derived from blood lymphocytes recognized several antigens presented by different HLA class I molecules on MEL.A. The MEL.B cells resisted lysis by these CTLs because they have lost expression of most HLA molecules, suggesting that they were selected in vivo by the anti-MEL.A CTL response. One of the MEL.A antigens was shown to result from a point mutation in the tumor. Here we report the cloning of a gene that encodes two other MEL.A antigens. This new gene, MUM-2, is expressed ubiquitously. In the melanoma cells of patient LB33, it contains a point mutation that changes one amino acid in the translated protein. Two different antigenic peptides, one presented to CTL by HLA-B44 molecules and another by HLA-C6 molecules, overlap and contain the mutated residue. Gene MUM-2 is homologous to an essential yeast gene, bet5, that was recently shown to be implicated in the vesicular transport of proteins from the endoplasmic reticulum to the Golgi. In a mutant yeast with a disrupted bet5 gene, both the wild-type and the mutated MUM-2 genes could complement for bet5 function. These results indicate that the antigenic mutation does not destroy the function of the protein, a function that is conserved in eukaryotic cells. The identification of these antigens suggests that point mutations could be the major cause of the strong immunogenicity of MEL.A cells.

Amino Acid Sequence↗
PubMed1999

Effects of chronic median nerve compression at the wrist on sensation and manual skills.

The aim of this study was to analyse the functional impairments caused by chronic median nerve compression at the wrist on hand sensation and manual skill. Hand function was assessed in 11 patients (8 women and 3 men) with severe carpal tunnel syndrome (CTS) and compared with that of an age- and sex-matched control group. Apart from CTS, the subjects were healthy and the electrodiagnostic examination was normal. The pressure and vibration detection thresholds of the index finger were partially impaired and statistically different (P<0.05) when compared with controls, suggesting a reduction of tactile acuity in the territory of the median nerve. The thermal thresholds were identical in both groups, suggesting that the small-diameter fibres were not affected. When a small object was lifted and positioned in space, the coordination between the grip force and the vertical lifting force did not seem to be affected in our patients. They were able to modify their grip force according to the friction between the fingertips and the object, i.e. the more slippery the object, the higher the grip force. The unimanual Purdue Pegboard subtest results suggest that digital dexterity was also not significantly perturbed in our sample of CTS patients when compared with controls. Despite the severe abnormalities of median nerve conduction, our results suggest that chronic median nerve compression occurring in CTS induces partial impairment of tactile sensibility with minor impact on grasp force regulation and digital dexterity.

Carpal Tunnel Syndrome↗
PubMed1999

Derivation of tumor-specific cytolytic T-cell clones from two lung cancer patients with long survival.

We derived lung carcinoma cell lines from tumor material resected from a patient with small-cell lung cancer (SCLC) and from a patient with non-small-cell lung cancer (NSCLC). The patient with NSCLC was vaccinated with irradiated autologous tumor cells. The two patients enjoyed an exceptionally favorable clinical evolution and are currently without signs of cancer 10 and 8 yr after their diagnoses, respectively. Autologous mixed lymphocyte-tumor cell cultures (MLTC) were produced with blood lymphocytes stimulated with irradiated autologous tumor cells. The first patient's SCLC cells, which carried a small amount of human leukocyte antigen (HLA) class I molecules, were incubated with interferon-gamma (IFN-gamma) before being used as stimulator cells. A cytolytic T-lymphocyte (CTL) clone was derived that specifically lysed the IFN-gamma-treated SCLC cells but did not lyse untreated tumor cells or autologous lymphoblasts. Clones of autologous tumor-specific CTL, directed against the NSCLC cells of the other patient, were also obtained. These tumor cells carried a higher level of HLA class I molecules and were lysed by the CTL without incubation with IFN-gamma. Altogether, these results indicate that SCLC and NSCLC cancer cells can be recognized by autologous CTL, and might therefore be susceptible to specific immunotherapy.

Carcinoma, Non-Small-Cell Lung↗
PubMed1996

A peptide encoded by the human MAGE3 gene and presented by HLA-B44 induces cytolytic T lymphocytes that recognize tumor cells expressing MAGE3.

The human MAGE3 gene is expressed in a significant proportion of tumors of various histological types, but is silent in normal adult tissues other than testis and placenta. Antigens encoded by MAGE3 may therefore be useful targets for specific antitumor immunization. Two antigenic peptides encoded by the MAGE3 gene have been reported previously. One is presented to cytolytic T lymphocytes (CTL) by HLA-A1, the other by HLA-A2 molecules. Here we show that MAGE3 also codes for a peptide that is presented to CTL by HLA-B44. MAGE3 peptides containing the HLA-B44 peptide binding motif were synthesized. Peptide MEVDPIGHLY, which showed the strongest binding to HLA-B44, was used to stimulate blood T lymphocytes from normal HLA-B44 donors. CTL clones were obtained that recognized not only HLA-B44 cells sensitized with the peptide, but also HLA-B44 tumor cell lines expressing MAGE3. The proportion of metastatic melanomas expressing the MAGE3/HLA-B44 antigen should amount to approximately 17% in the Caucasian population, since 24% of individuals carry the HLA-B44 allele and 76% of these tumors express MAGE3.

Amino Acid Sequence↗
PubMed1996

Beta-thalassaemia in indigenous Belgian families: identification of a novel mutation.

The molecular basis of beta-thalassemia was investigated at the DNA level in 28 Belgians from 14 unrelated families. All the patients were heterozygous for beta-thalassaemia. Seven different mutations were identified using a combination of dot-blot hybridization with allele-specific oligonucleotide probes and direct automated fluorescence-based DNA sequencing. Among these mutations, four are commonly found in the Mediterraneans - codon 8 (-AA), IVS-I-1 (G --> A), IVS-I-6 (T --> C) and codon 39 (C --> T)-and two have occasionally been reported-initiation codon (T --> C) and codon 35 (C --> A). The last mutation, a -CC deletion at codons 38/39, appears to be a novel mutation and can routinely be investigated by AvaII restriction on amplified DNA. We report our findings, discuss the diversity of the mutations found in Belgium and show the usefulness of direct DNA sequencing in a population in which the molecular defects of beta-thalassaemia have yet to be characterized and in which screening is hampered by the wide range of potential mutations.

Belgium↗
PubMed1996

HLA class II-associated genetic susceptibility in idiopathic progressive sensorineural hearing loss.

To investigate the association between genes in the major histocompatibility complex and inner ear disease susceptibility at the DNA level, high-resolution genotyping for HLA class II (HLA-DR, -DQ, -DP) was performed by polymerase chain reaction-sequence-specific oligonucleotide reverse dot blot and polymerase chain reaction-restriction fragment length polymorphism analysis in 34 patients with idiopathic progressive sensorineural hearing loss (PSHL) and in 214 controls. The frequencies of DRB1*0301, DRB3*0101, DQB1*0201, and DPB1*0401 were significantly increased in patients with idiopathic PSHL compared with controls. The DQB1*0301 allele was significantly decreased in the patients. A linkage disequilibrium was probably responsible for the concomitant increase of both DRB1*0301 and DRB3*0101 alleles in patients. The increase of DQB1*0201 in patients was associated with the DRB1*0301 allele. In addition, the telomeric DPB1*0401 allele may act as an independent risk factor. The DQB1*0301 allele may have a protective role in the pathogenesis of idiopathic PSHL. These results suggest that the specific HLA class II gene products may confer susceptibility or resistance to idiopathic PSHL.

Adult↗
PubMed1995

HLA class II genotyping: two assay systems compared.

In the last few years, a variety of DNA-based human leukocyte antigen (HLA) typing methods have emerged, revealing the extreme polymorphism of HLA genes. This polymorphism makes it difficult for a clinical laboratory to establish the best HLA typing strategy. In this study we have compared two techniques for performing HLA-DRB typing: a commercial rapid assay based on the polymerase chain reaction (PCR) followed by reverse dot-blot hybridization of the PCR products (the Inno-LiPA assay), and a method based on PCR followed by restriction fragment length polymorphism analysis. We found that both methods provide reliable results with a high rate of concordance (97%) and that Inno-LiPA is convenient for large-scale routine typing. However, if a high-resolution allelic typing is required, each method lacks accuracy but using them in association improves the accuracy of the results.

Alleles↗
PubMed1994

[Rochalimaea henselae, Afipia felis and cat-scratch disease].

Several years ago, Rochalimaea henselae has emerged as an agent of bacillary angiomatosis, bacillary peliosis and recurrent septicaemia that generally occur in patients infected with human immunodeficiency virus. An aetiologic role in cat scratch disease is also suspected widely on the basis of a serologic survey. Its slow growth and its culture requirement explain that this pathogen, a gram-negative bacterium, could not be isolated until 1990. Moreover, blood and tissue samples request lysis and crushing for recovering by culture. The clinical, histological, microbiological and pathogenic aspects of these infections are described and discussed.

AIDS-Related Opportunistic Infections↗