PubMed Health⌕ Search

Biomedical subjects

D H Kono

Publications and source records attributed to D H Kono.

66 records · Page 4Linked to original sources
PubMed1988

Two minor determinants of myelin basic protein induce experimental allergic encephalomyelitis in SJL/J mice.

Experimental allergic encephalomyelitis (EAE) is an autoimmune demyelinating disease of the central nervous system (CNS) that occurs after immunization of animals with myelin basic protein (MBP). The disease is a prototype model for the study of antigen-specific T helper cell-mediated autoimmune disease. In SJL/J mice, EAE is mediated by T helper cells directed against a 40-amino acid COOH-terminal peptic fragment of mouse small MBP. To identify the minimal T cell epitopes of MBP responsible for EAE, overlapping peptides completely encompassing the epitopes within this region were synthesized. A 28-residue peptide of mouse MBP spanning residues 87-114 (pM87-114) was able to elicit both a strong T cell response and chronic relapsing disease. To better localize the T cell epitopes, shorter peptides within this region were synthesized and two overlapping peptides, pM87-98 and pM91-104, were able to induce EAE. T cell clones and bulk lymph node cell populations reactive with pM87-98 did not respond to pM91-104. However, lymph node cells reactive with pM91-104 also reacted with pM87-98, thus showing that these two peptides represent contiguous, but distinct encephalitogenic epitopes and that both these epitopes may be contained within pM87-98. In addition, pM87-114 and pM87-98 were found to be minor determinants of the total T cell response to rat and rabbit MBP. The restricted response to MBP in SJL/J mice is similar to that of the PL/J mice in that each appears to have only a single peptide region in MBP that elicits encephalitogenic T cells. However, within the region studied, there were two if not more T cell epitopes. This differs from the single encephalitogenic PL/J epitope. These findings of a single encephalitogenic peptide region with multiple T cell epitopes and the fact that encephalitogenic T cell epitopes may be subdominant have implications for the design of treatments directed at the T cell receptor-MHC-peptide epitope complex in autoimmune disease.

Animals↗
PubMed1987

A Yersinia pseudotuberculosis protein which cross-reacts with HLA-B27.

The most-debated question in the investigation of the spondyloarthropathies has been whether there is molecular mimicry between host HLA-B27 antigens and the arthritis-causing pathogens. We have generated a monoclonal anti-HLA-B27 antibody in our laboratory and have used a radioimmunoassay to screen a panel of bacterial species. Two strains of Yersinia pseudotuberculosis were found to be highly reactive. The cross-reactive Yersinia component was identified by Western blot to be a 19,000 component. A preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis chromatography apparatus was constructed to isolate milligram quantities of this component. To verify that the component carried the HLA-B27-specific epitope, rabbits were hyperimmunized with the purified materials. Affinity-purified antibodies from one of the immunized rabbits indeed carried anti-HLA-B27 activity. Last, antibodies generated against synthetic peptides derived from the HLA-B27.1 amino acid sequence were tested against the Yersinia component. Positive reactivity was found with antibodies generated against a peptide spanning residues 69-83 of the HLA-B27.1 protein. Since this resides in the segment responsible for the allotypic specificity of the antigen, these experiments establish the presence of molecular mimicry to a high degree of confidence.

Antibodies, Monoclonal↗
PubMed1986

Mimicry of human histocompatibility HLA-B27 antigens by Klebsiella pneumoniae.

Anti-HLA-B27 monoclonal antibody M2, which was relatively specific for human histocompatibility antigen HLA-B27, was used to test several bacteria, some of which could potentially induce chronic arthritis in HLA-B27-positive individuals. Using the Western blot procedure, we observed positive reactions with 80,000- and 60,000-dalton antigens with one strain of Klebsiella pneumoniae. Reactivity was not observed with five other monoclonal antibodies which were not reactive with HLA-B27 antigens, nor was reactivity observed with seven other gram-negative bacteria, irrespective of their arthritis-causing potential. To test the validity of our observation, the 80,000-dalton Klebsiella cross-reactive antigen was isolated and used to generate an immune guinea pig serum. We found that the reactivity of this guinea pig serum with Klebsiella envelopes in an enzyme-linked immunosorbent assay was adversely affected by absorption with HLA-B27-positive cells. Our results support the existence of mimicry between HLA-B27 antigens and bacteria.

Antibodies, Monoclonal↗
PubMed1985

A heat-modifiable outer membrane protein carries an antigen specific for the species Yersinia enterocolitica and Yersinia pseudotuberculosis.

The outer membranes of gram-negative bacteria are considered to be of importance in host-bacteria interaction, in protective immunity, and occasionally in subclassification within a species. In this study, the outer membranes of several strains of Yersinia enterocolitica and Y. pseudotuberculosis were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). It was found that the appearance of the major proteins depended on the temperature at which they were solubilized in SDS. A protein was identified with the use of two-dimensional gels and preparative SDS-PAGE, which was equivalent to the "heat-modifiable protein" (protein II) of other Enterobacteriaceae species. A monoclonal antibody, 4G1, was generated against an isolated preparation of this Y. enterocolitica protein. This antibody was tested with whole cell bacterial antigens of 46 individual bacterial strains. The reactive strains included only Y. enterocolitica and Y. pseudotuberculosis. In addition, the reactivity of the 4G1 monoclonal antibody preparation could be absorbed only with Y. enterocolitica and Y. pseudotuberculosis, and not with other strains of bacteria. The reactivity of this 4G1 monoclonal antibody was also tested by the Western Blot technique. Six individual strains were tested: a Y. enterocolitica serotype 0:3, a Y. enterocolitica serotype 0:9, an Escherichia coli, a Salmonella typhimurium, a Shigella flexneri, and a Klebsiella pneumoniae. The 4G1 antibody reacted with only the proteins of the two Y. enterocolitica strains. In conclusion, the equivalent of the heat-modifiable protein was present in Y. enterocolitica and Y. pseudotuberculosis. Moreover, this protein also carried a species-specific antigenic determinant.

Absorption↗
PubMed1985

A Yersinia enterocolitica serotype 0:3 lipopolysaccharide-specific monoclonal antibody reacts more strongly with bacteria cultured at room temperature than those cultured at 37 degrees C.

It has been suggested that the O-side chains of the lipopolysaccharide (LPS) of serotype 0:3 strains of Yersinia enterocolitica vary quantitatively and qualitatively depending on whether they are cultured at 37 degrees C or 25 degrees C. It is uncertain whether this affects the expression of the serotype-specific antigens that are probably carried on the LPS. We studied this question with a serotype 0:3-specific monoclonal antibody, 2C1. This monoclonal antibody immunoprecipitated a 39K major protein from detergent-solubilized 125I-labeled Yersinia preparation. However, results of Western blot experiments demonstrated that the antigens reactive with 2C1 were not actually the 39K protein but the O-side chains of the LPS. Significantly, reactivity could be detected whether the bacteria were cultured at room temperature or at 37 degrees C. However, absorption experiments confirmed that there were less accessible antigenic determinants on the 37 degrees C-LPS. The LPS preparations were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining. These SDS-PAGE profiles showed that less O-side chains were present in the 37 degrees C-LPS. Hence, the most likely explanation for our observation is that the 37 degrees C incubation condition induced a partial smooth to rough transition of the Yersinia LPS with a decrease in the amount of 2C1-reactive antigen.

Absorption↗
PubMed1985

Ye-1, a monoclonal antibody that cross-reacts with HLA-B27 lymphoblastoid cell lines and an arthritis causing bacteria.

A monoclonal antibody, Ye-1, was generated by immunizing BALB/c mice with Yersinia enterocolitica. This antibody also reacted with all of 12 B27 positive lymphoblastoid cell lines, but only four of 31 B27 negative ones. Three of the four reactive B27 negative cell lines were B7 positive. A B27 positive cell line which has lost the B27 expression because of experimentally-induced mutation became unreactive with the Ye-1. These findings support the possibility that there is cross-reactivity between HLA-B27 antigens and Y. enterocolitica.

Animals↗
PubMed1985

Rabbit antisera against three different bacteria which can induce reactive arthritis: analysis by ELISA, immunoprecipitation and Western Blot.

Three strains of bacteria which induce reactive arthritis were collected: a Shigella flexneri, designated 7060; another Sh. flexneri, designated 316; and a Yersinia enterocolitica of serotype 03. Rabbit antisera were generated against each of them to test for the extent and nature of cross-reactivity among these strains. When analysed by the ELISA technique, antisera against 7060 and 316 showed strong cross-reactivity with Y. enterocolitica. In contrast, the reaction of antisera prepared against putatively non-arthritis-causing bacteria reacted several-folds less. Using immunoprecipitation, sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western Blot procedures, a 92,000 MW cross-reactive antigen on the Yersinia was identified. The antigen was present on the outer membranes of the Y. enterocolitica, and enzyme digestion experiments showed that this antigen was protein in nature.

Animals↗
PubMedDate not supplied

The genes of systemic autoimmunity.

Autoimmune diseases include a wide spectrum of disorders, which have been divided into systemic and organ-specific disorders. Lupus, the prototypic systemic autoimmune disease, is characterized by female predominance, multiorgan pathology, and autoantibodies, primarily directed against nuclear antigens. The disease is heterogeneous, with variable organ involvement, serology, and clinical course. Susceptibility to lupus is inherited as a polygenic trait with added contributions from environmental and stochastic variance. Concerted efforts have recently been made by several laboratories to define the genetic basis of this disease in predisposed mice and humans. The identification of the Fas/FasL defects in lpr and gld lupus mice was the first example of spontaneous mutations of apoptosis-promoting genes being associated with systemic autoimmunity. This research was instrumental in clarifying the roles of these genes in tolerance and immunoregulation, and in extrapolating these results to other autoimmune diseases, as well as cancer and transplantation. To these findings have been added those from transgenic and gene knockout mouse studies that have helped to define the systemic autoimmunity-inducing or -modifying effects of specific genes in normal background and lupus-congenic mice. In addition, the findings from genome-wide searches have begun to identify predisposing loci (and ultimately genes) for the spontaneous lupus-like diseases in various mouse strains and in humans. The emerging picture is that multiple genetic contributions can independently lead to systemic autoimmunity in mice, which reinforces the view that human lupus may be similarly composed of diverse genotypes. This complexity underscores the importance of defining the predisposing alleles and mechanisms of action, an undertaking that is certainly feasible given current technologies and future advances in the definition of mammalian genomes.

Animals↗
PubMedDate not supplied

An animal model to study serum immunoglobulin response to infection by Yersinia enterocolitica.

Using an Elisa method, we tested whether the serum immunoglobulin response of CBA/H mice, orally infected by a serotype 03 strain of Yersinia enterocolitica was of sufficient magnitude to serve as an experimental model. We found that the dose of bacteria administered was important. At a dose of 10(10)-10(12) bacteria per mouse, easily detectable IgM, IgG and IgA antibody titers could be obtained. At 10(8) bacteria per mouse, although diarrhea occurred and Yersinia was shed into the stool, the antibody titers were minimal.

Animals↗
PubMedDate not supplied

Absence of lymphotoxic antibodies in patients with Yersinia-induced arthritis, Reiter's syndrome and ankylosing spondylitis.

Serum samples from patients with Reiter's syndrome, ankylosing spondylitis, Yersinia-induced arthritis and Yersinia infections not followed by arthritis were collected and assayed for complement-dependent cytotoxicity, using a standard dye-exclusion microcytotoxicity technique. A total of eighty-nine serum samples derived from these patients were compared to those of forty control subjects, using as target cells six different cultured cell line cells and peripheral blood mononuclear cells isolated from the blood samples of four subjects. Serum samples from only five of the subjects demonstrated cytotoxicity. This did not depend on whether the target cells were HLA-B27 or not. Hence, if antilymphocytic auto-antibodies are present in these patients, they will require a different technique for their detection.

Adolescent↗