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L Fugger

Publications and source records attributed to L Fugger.

At least 55 records · Page 3Linked to original sources
PubMed1996

Specificity of an HLA-DRB1*0401-restricted T cell response to type II collagen.

A panel of HLA-DRB1*0401-restricted CD4+ mouse T cell hybridomas specific for bovine type II collagen were generated from transgenic mice expressing the human HLA-DRA1*0101/-DRB1*0401 and CD4 molecules. The vast majority recognized a single peptide determinant corresponding to residues 261-273 (CII 261-273). This determinant was rapidly defined by the use of a predictive algorithm for peptide binding to DRB1*0401. CII 261-273 is conserved in bovine and human type II collagen and overlaps with an important I-A q - restricted T cell determinant in mice with collagen-induced arthritis. This study demonstrates how HLA-DR and human CD4-transgenic mice can be used to identify a T cell epitope in a potential or candidate autoantigen.

Amino Acid Sequence↗
PubMed1996

Quantitative analysis of peptides from myelin basic protein binding to the MHC class II protein, I-Au, which confers susceptibility to experimental allergic encephalomyelitis.

BACKGROUND: An important issue in autoimmune diseases mediated by T cells, such as experimental allergic encephalomyelitis (EAE), is the affinity of the disease-inducing determinants for MHC class II proteins. Tolerance, either due to clonal deletion or anergy induction, is thought to require high-affinity interactions between peptides and MHC molecules. Low-affinity binding is compatible with the hypothesis that breaking tolerance to self proteins does not have to occur for onset of disease. In contrast, a high-affinity interaction implies that an event leading to a breakdown of tolerance is central to the autoimmune process. MATERIALS AND METHODS: Detergent-solubilized and affinity-purified I-Au was incubated with varying concentrations of a set of peptides from myelin basic protein and a biotinylated peptide agonist. The specific complexes were separated from excess peptide by capture on antibody-coated plates, and the affinity of the peptides was measured by adding europium-labeled streptavidin and measuring the resultant fluorescence. RESULTS: The immunodominant and encephalitogenic determinant, Ac 1-11, was shown to bind to I-Au relatively poorly (IC50 = 100 microM), demonstrating that in this protein, immunodominance did not correlate with high-affinity binding. In contrast with the natural sequence, the ability of shorter analogs to induce EAE did correlate with their apparent affinity. CONCLUSIONS: The dominance of the natural determinant does not arise from a high-affinity interaction with the MHC class II molecule. This suggests that other mechanisms are operative and that the specific T cell for this peptide/MHC ligand is of high affinity.

Amino Acid Sequence↗
PubMed1994

Expression of HLA-DR4 and human CD4 transgenes in mice determines the variable region beta-chain T-cell repertoire and mediates an HLA-DR-restricted immune response.

Inherited susceptibility to rheumatoid arthritis is associated with genes encoding the human major histocompatibility complex class II molecule HLA-DR4. To study the immune function of HLA-DR4 and attempt to generate a murine model of rheumatoid arthritis we have produced triple transgenic mice expressing HLA-DRA*0101, -DRB1*0401, and human CD4. The expression of the HLA transgenes is driven by the promoter of the murine major histocompatibility complex class II I-E alpha gene and was found on murine cells that normally display major histocompatibility complex class II molecules. The expression of the human CD4 transgene is driven by the murine CD3 delta-promoter, and therefore its gene product was found on cells that express murine CD3. In contrast to other HLA-DR and HLA-DQ transgenic mouse lines, the transgenes are functional in our mice. In H-2 I-E-negative transgenic mice, T cells expressing variable region beta chain (V beta) 3, 5, 6, 7, 9, 11, 12, or 13 were either absent or significantly reduced, in contrast to H-2 I-E-negative nontransgenic littermates. In addition, the peptide antigen influenza A virus hemagglutinin 307-319, which binds to the HLA-DRA*0101/-DRB1*0401 heterodimer with high affinity and induces an HLA-DR-restricted and CD4+ T-cell response in humans, also induced a T-cell response in the triple transgenic mice but not in nontransgenic littermates. Thus, these transgenic mice should permit extensive testing of the antigen-presentation capabilities of the HLA-DRA*0101/-DRB1*0401 molecule.

Animals↗
PubMed1994

Prediction of peptide affinity to HLA DRB1*0401.

Hydrogen bonding between conserved amino acids in the HLA DR and the peptide backbone of the ligand both provide the majority of free energy of binding and force the peptide ligands to adopt a similar extended conformation. Consequently the corresponding side chains of all peptides interact with similar pockets in the binding site. For peptides of a common length the contribution of the peptide backbone can be treated as a constant and the differential affinity can be viewed as a simple sum of the side chain interactions. These can be quantified by measuring the effects of each of the naturally occurring amino acids in the context of a simplified polyalanine backbone containing an aromatic amino acid to orient the peptide unequivocally in the binding site. The dataset of the relative contributions can be used to predict quantitatively the affinity of any peptide sequence.

Amino Acid Sequence↗
PubMed1994

Major histocompatibility complex-encoded antigen processing gene polymorphism in IDDM.

Susceptibility to insulin-dependent diabetes mellitus (IDDM) is greatly influenced by polymorphisms in the genes of the class II region of the human leukocyte antigen (HLA) complex. The complexity of this genetic association and the lack of a direct proof of involvement of HLA class II genes in human IDDM have continued to support speculation on a possible role of genes encoded in the close vicinity of these loci in IDDM. Because the recently discovered transporter associated with antigen processing (TAP) and large multifunctional protease (LMP) genes are encoded in the HLA class II region and are implicated in the processing of antigenic proteins for presentation by HLA class I molecules, they are additional candidates for a role in IDDM pathogenesis. We have analyzed genomic and coding sequence polymorphisms in the LMP2, TAP1, and TAP2 genes of 77 Danish IDDM patients and 102 control subjects. Although patients and control subjects did not differ in TAP1 and LMP2 alleles, we found a striking absence of the TAP2 allele B (long form) in IDDM patients. An analysis of the TAP2 alleles in individual DR types, however, revealed that this phenomenon is likely to be caused by linkage disequilibrium between the two loci. Thus, polymorphisms in the TAP and LMP genes are unlikely to be associated with IDDM.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Immune response to glutamic acid decarboxylase correlates with insulitis in non-obese diabetic mice.

Knowing the autoantigen target(s) in an organ-specific autoimmune disease is essential to understanding its pathogenesis. Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease characterized by lymphocytic infiltration of the islets of Langerhans (insulitis) and destruction of insulin-secreting pancreatic beta-cells. Several beta-cell proteins have been identified as autoantigens, but their importance in the diabetogenic process is not known. The non-obese diabetic (NOD) mouse is a murine model for spontaneous IDDM. Here we determine the temporal sequence of T-cell and antibody responses in NOD mice to a panel of five murine beta-cell antigens and find that antibody and T-cell responses specific for the two isoforms of glutamic acid decarboxylase (GAD) are first detected in 4-week-old NOD mice. This GAD-specific reactivity coincides with the earliest detectable response to an islet extract, and with the onset of insulitis. Furthermore, NOD mice receiving intrathymic injections of GAD65 exhibit markedly reduced T-cell proliferative responses to GAD and to the rest of the panel, in addition to remaining free of diabetes. These results indicate that the spontaneous response to beta-cell antigens arises very early in life and that the anti-GAD immune response has a critical role in the disease process during this period.

Aging↗
PubMed1993

Antigen processing gene polymorphisms in HLA-DR2 multiple sclerosis.

The association between multiple sclerosis (MS) and alleles of the HLA class II genes indicates that at least one MS susceptibility gene is linked to the HLA class II region. However, the actual locus responsible has not been precisely identified. The recent cloning of new genes involved in antigen processing that map within the HLA class II region led us to investigate--using the restriction fragment length polymorphism (RFLP) technique and sequence-specific oligonucleotide analysis--whether these genes might play a role in conferring susceptibility to MS. We studied large multifunctional protease (LMP) 2 and 7 and transporter associated with antigen processing (TAP) 1 and 2 gene polymorphisms in 60 HLA-DR2 MS patients and 60 HLA-DR2 healthy subjects and found no specific or preferential RFLP patterns or coding sequence variants in the patient group. Our data do not support a role for these genes in MS susceptibility.

Adult↗
PubMed1992

DNA polymorphism of HLA class II genes in primary biliary cirrhosis.

We investigated the DNA restriction fragment length polymorphism of the major histocompatibility complex class II genes: HLA-DRB, -DQA, -DQB, DPA, -DPB, the serologically defined HLA-A, B, C, DR antigens, and the primed lymphocyte typing defined HLA-DP antigens in 23 Danish patients with primary biliary cirrhosis (PBC) and in healthy Danes. The following genetic markers were found with increased frequencies in PBC: HLA-B8 (relative risk, RR = 2.4, P less than 0.05, 'corrected' P greater than 0.05), HLA-DR3 (RR = 3.4, P less than 0.01, 'corrected' P less than 0.05), the DRB3*01/02/03 (DRw52) associated DRB Bgl II 9.1 kilobase (kb) fragment (RR = 2.9; P less than 0.05, 'corrected' P greater than 0.05), the DQA1*0501 associated DQA Taq I 4.8 kb fragment (RR = 3.1; P less than 0.05, 'corrected' P greater than 0.05), the DQB1*0201 (DQw2) associated DQB Hin dIII 11.5 kb fragment (RR = 3.1; P less than 0.05, 'corrected' P greater than 0.05). No DNA fragments specific for DRB1*0301 (DR3) could be identified. The frequencies in PBC of other genetic markers including DRw8, DRB1*08, HLA-DP antigens, DPA, and DPB genes did not differ significantly from those in controls. The associations between PBC and B8, DR3, DQA1*0501, and DQB1*0201, which are frequently found together on the same haplotype, are at variance with recent reports on associations between PBC and Drw8. The discrepancy suggests that PBC is genetically heterogenous.

Genes, MHC Class II↗
PubMed1991

Restriction fragment length polymorphism of two HLA-B-associated transcripts genes in five autoimmune diseases.

The restriction fragment length polymorphism of the two human HLA-B-associated transcripts (BATs) genes, BAT1 and BAT2, identifying polymorphic bands of 12, 8, 2.5, and 1.1 kb, and at 3.3, 2.7, 2.3, and 0.9 kb, respectively, was investigated in patients with primary biliary cirrhosis (PBC), systemic lupus erythematosus (SLE), pauciarticular juvenile rheumatoid arthritis (P-JRA), rheumatoid arthritis (RA), and primary Sjögren's syndrome (pSS), and in healthy Danes. The BAT2/RsaI 2.7-kb band fragment was more frequent in PBC, pSS, and SLE than in controls, but the p values did not reach significance when corrected for multiple comparisons. For pSS and SLE, the associations may be secondary to primary associations with HLA-B8 because the BAT2/RsaI 2.3-kb band, which is allelic to the BAT2/RsaI 2.7-kb band, is strongly negatively associated with HLA-B8 and HLA-DR3. The only significance obtained shows that the HLA-B8 frequency is increased in BAT2/RsaI 2.7-kb positive pSS patients as compared to the corresponding controls indicating that the HLA-B8 association may be strongest. No missing or extra DNA fragments were observed in the disease groups when compared with controls indicating that gross deletions or duplications of the BAT1 and BAT2 genes in the patients are unlikely. In conclusions, it cannot be excluded that the BAT2/RsaI 2.7-kb band may contribute to the susceptibility to PBC, pSS, and SLE.

Autoimmune Diseases↗
PubMed1991

DNA polymorphism of HLA class II genes in pauciarticular juvenile rheumatoid arthritis.

We investigated the DNA restriction fragment length polymorphism (RFLP) of the major histocompatibility complex (MHC) class II genes: HLA-DRB, -DQA, -DQB, DPA, and -DPB in 54 patients with pauciarticular juvenile rheumatoid arthritis (PJRA) and in healthy Danes. The frequencies of DNA fragments associated with the following HLA class II genes were increased in PJRA when compared to normal controls: DRB1*08 (DRw8) (35.2% vs 10.3%, RR = 4.6, p less than 10(-3), DRB3*01/02/03 (DRw52) (76.3% vs 48.1%, RR 3.5, p less than 10(-3)), DQA1*0401 (41.0% vs 7.4%, RR = 7.9, p less than 10(-3)), DQA1*0501 (55.6% vs 29.7%, RR = 3.0, p less than 10(-2), DQB1*0301 (DQw7) (46.2% vs 17.5%, RR = 4.0; p less than 10(-2)), DPA1*0201 (44.2% vs 7.9%, RR = 8.7, p less than 10(-5)), and DPB1*02 (DPw2) (40.7% vs 7.1%, RR = 8.5, p less than 10(-6)). The frequency of DRB1*11 was not significantly increased. The frequencies of DNA fragments associated with the following HLA class II genes were decreased in PJRA although not statistically significantly so after 'correction' of p values: DRB1*04 (14.8% vs 40.2%, RR = 0.27; p less than 10(-3)), DRB1*07 (0% vs 25.9%, RR = 0.04, p less than 10(-3)), DRB4*0101 (DRw53) (25.9% vs 53.6%, RR = 0.31, p less than 10(-3)), DQA1*0102 (11.6% vs 36.0%, RR = 0.25, p less than 10(-4)), and DQA1*0201 (2.6% vs 34.2%, RR = 0.05, p less than 10(-2)).(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Juvenile↗
PubMed1990

Technical aspects of typing for HLA-DP alleles using allele-specific DNA in vitro amplification and sequence-specific oligonucleotide probes. Detection of single base mismatches.

The polymerase chain reaction (PCR) is an effective method for in vitro DNA amplification which combined with probing with synthetic oligonucleotides can be used for, e.g., HLA-typing. We have studied the technical aspects of HLA-DP typing with the technique. DNA from mononuclear nucleated cells was extracted with either a simple salting out method or phenol/chloroform. Both DNAs could be readily used for PCR. The MgC2 concentration of the PCR buffer and the annealing temperature of the thermal cycle of the PCR were the two most important variables. The MgCl2 concentration and the temperature must be carefully titrated for each primer pair in the PCR. The influence of mismatches between the primer and the DNA template were studied and we found that, by using primers differing only from each other at the 3' end, cross-amplification of closely homologous alleles could be avoided. Thus, single base mismatches may be detected in the PCR and typing for HLA-DP gene variants, which differ for only one base, may be performed.

Alleles↗
PubMed1990

DNA typing for HLA-DPB1*02 and -DPB1*04 in multiple sclerosis and juvenile rheumatoid arthritis.

DP gene typing using in vitro DNA amplification combined with sequence-specific oligonucleotide probes (SSOP) has recently been reported. The amplification step may be specific for the HLA-DPB locus, or it may be specific for one or a group of HLA-DPB alleles, thus increasing the discriminatory power of the system. We report the combined use of group-specific DNA in vitro amplification followed by SSOP in typing for DPB1*02 and DPB1*04 variants. The method was used to type for these variants in 96 randomly selected, healthy Danes, in 37 patients with pauciarticular juvenile rheumatoid arthritis (PJRA), and in 38 patients with multiple sclerosis (MS). Increased frequencies of the cellularly defined HLA-DPw2 in PJRA and of HLA-DPw4 in MS have previously been reported. In the patient groups, the frequencies of the DPB1*02 and DPB1*04 variants did not differ significantly from those expected based on the cellularly defined HLA-DP types of the patients and the frequencies of the DPB1*02 and DPB1*04 variants among healthy Danes.

Amino Acid Sequence↗
PubMed1990

Tumor necrosis factor alpha gene polymorphism in multiple sclerosis and optic neuritis.

The NcoI tumor necrosis factor (TNF alpha) polymorphism was studied in relapsing/remitting multiple sclerosis and monosymptomatic optic neuritis. The frequency of the NcoI marker phenotypes did not differ between healthy controls and the two disease groups. No extra or missing DNA fragments were observed in the disease groups when compared with controls.

Adolescent↗