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D T Yu

Publications and source records attributed to D T Yu.

At least 37 records · Page 2Linked to original sources
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

The lysine requirement of young growing male guinea pigs.

The lysine requirement of young, growing male guinea pigs was investigated by using crystalline amino acid diets containing 3.58% nitrogen. One hundred eighty-seven 3-wk-old guinea pigs were fed one of 10 crystalline amino acid diets ranging from 0.4 to 2.0% lysine or the control diet consisting of 30% casein in four 21-d performance trials. Diets were evaluated on the basis of changes in body weight, nitrogen retention, carcass weight, gastrointestinal tract weight, liver weight, hematocrit and hemoglobin plus carcass weight, gastrointestinal tract weight and liver weight as percentages of live body weight. A 0.7% dietary lysine level (0.875% lysine X HCl) was the lowest that gave results similar to those attained when casein or higher levels of lysine were fed.

Amino Acids↗
PubMed1985

Cystic renal involvement in tuberous sclerosis.

We describe two cases of unusual presentation of tuberous sclerosis with cystic renal involvement. A 19-month-old white male who was initially misdiagnosed as having polycystic kidney disease of "adult-type" developed petit mal seizures and small "ash-leaf" depigmented areas, raising a suspicion of tuberous sclerosis. Computerized tomography (CT) of the brain revealed periventricular calcifications, confirming the diagnosis of tuberous sclerosis. A 15 3/4-year-old black female with tuberous sclerosis showed acceleration of renal failure. Computerized tomography scan of the abdomen showed cystic lesions of the kidneys. In young children with cystic renal involvement but a negative family history of tuberous sclerosis or polycystic kidney disease, a CT scan of the brain should assist in the diagnosis. A CT scan or ultrasound examination of the abdomen will differentiate cystic renal lesions from angiomyolipoma of the kidneys.

Adolescent↗
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

Antibodies against Yersinia enterocolitica in patients with Reiter's syndrome.

Reiter's syndrome can be induced by several different bacteria. A frequent cause in Finland is Yersinia enterocolitica serotypes 03 and 09, but these strains are rarely found in the United States. Although this does not exclude the possibility that U.S. patients with Reiter's syndrome have been infected with Yersinia, it is more likely that they develop Reiter's syndrome as a consequence of infection by non-Yersinia arthritis-causing organisms that share certain determinants with Yersinia organisms. We used radioimmunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis to analyze the serum antibodies against iodine 125-labeled, detergent-solubilized serotype 03 Y. enterocolitica. Our results demonstrated that most serum samples of United States subjects precipitate three to five radioactively labeled Yersinia molecules. A Yersinia antigen of 88K appeared to be of possible discriminatory value. Protein A-reacting antibodies directed against this antigen were detected in only two of twenty-five patients with rheumatoid arthritis and only seven of 44 normal control subjects, compared with 18 of 27 patients with Reiter's syndrome (p less than 0.005) and eight of 16 patients with ankylosing spondylitis (p less than 0.01). Our results indicate that, despite the relatively rare occurrence of Y. enterocolitica serotypes 03 and 09 infection in the United States, examination of the immune response to the serotype 03 Yersinia strain is a promising approach to the study of Reiter's syndrome in the United States.

Adolescent↗
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↗
PubMed1979

Ia determinants on stimulated human T lymphocytes. Occurrence on mitogen- and antigen-activated T cells.

Human T-cell blasts were generated by stimulation with mitogens and antigens. A proportion of these blasts expressed Ia antigens detectable by immunofluorescence with both allo- and hetero-antiserums. The maximal expression of Ia antigens was delayed and usually occurred after the peak of blastogenesis. Among the three mitogens used, pokeweed mitogen (PWM) was most effective in giving a high percentage and intense Ia staining of T-cell blasts. Phytohemagglutinin and concanavalin A blasts gave weaker and lower percentages of Ia staining. Activation by alloantigens and soluble antigens such as tetanus toxoid and purified protein derivative resulted in Ia expression on T cells comparable to PWM stimulation. Depletion of Ia+ cells from freshly isolated T cells with anti-Ia and complement decreased subsequent Ia expression, suggesting that a proportion of Ia+ blasts were derived from Ia-bearing peripheral blood T cells. When the specificities of the Ia antigens on T-cell blasts were examined with alloantiserums, it was evident that the T blasts expressed similar HLA-DR determinants to those on B cells from the same donor; occasional minor differences between stimulated T cells and autologous B-cell lines or fresh B cells were encountered.

Cells, Cultured↗
PubMed1978

Glucocorticoids administered in vivo inhibit human suppressor T lymphocyte function and diminish B lymphocyte responsiveness in in vitro immunoglobulin synthesis.

The effects of corticosteroid given in vivo on human lymphocyte subpopulation function were investigated using an in vitro system of pokeweek mitogen-stimulated immunoglobulin production. Peripheral blood lymphocytes were obtained from normal volunteers before and 4 h after the intravenous administration of methylprednisolone. Unfractioned peripheral blood lymphocytes showed a consistent decrease (mean congruent with 50%) in immunoglobulin and total protein synthesis after steroid administration. Utilizing separated thymus-derived (T) and bone marrow-derived (B) lymphocyte fractions, the pathophysiology of this alteration in immunoglobulin production was elucidated. B lymphocytes obtained after steroid treatment showed a markedly diminished immunoglobulin response (20% of normal) to normal T lymphocytes and to normal T cells that had been irradiated to remove suppressor T lymphocyte function. All major classes of immunoglobulin (IgG, IgM, and IgA) were affected. T lymphocytes procured after steroid administration were capable of providing normal amounts of T cell help for B cells in immunoglobulin production. However, suppressor T lymphocyte activity, observed with normal T lymphocytes at high T to B cell ratios, was absent from the post-steroid T lymphocytes. This loss of suppressor T lymphocyte function was not due to the presence of excess help as irradiated pre- and poststeroid T cells provided equal amounts of helper activity. On recombining the poststeroid treatment B cells, which are hyporesponsive in immunoglobulin synthesis, with the posttreatment T lymphocytes, which lack suppressor activity, diminished amounts of immunoglobulin were produced which correlate well with the effects observed with unseparated cells. Thus, corticosteroids have differential effects on the lymphocyte populations involved in immunoglobulin biosynthesis. B cell responsiveness is diminished, suppressor T lymphocyte activity is removed, and helper T lymphocyte function is unaffected.

Adult↗
PubMed1978

Cellular collaboration in the production of human leucocyte migration inhibition factor.

The participation of cell subpopulations in the expression of leucocyte migration inhibition factor (LMIF) in response to Concanavalin A and Protein A was evaluated for cells isolated from the peripheral blood of five healthy subjects. LMIF activity could not be attributed to the function of T cells, B enriched cells, or monocytes acting alone, or to a combination of B enriched cells and monocytes. The LMIF response was the result of a collaborative event that occurred between T cells and B enriched cells, or between T cells and monocytes.

B-Lymphocytes↗
PubMed1978

Effect of corticosteroids on committed lymphocytes.

Human peripheral blood lymphocytes were cultured for 48 hr with concanavalin A. The amount of [3H]thymidine incorporated during the last 4 hr of culture, as well as the percentage of rosettes of activated lymphocytes generated, were assayed at the 48th hr. Adding 0.1 M alpha-methyl-D-mannoside (MAM) at progressively later times after the initiation of culture caused progressively less suppression because of the commitment phenomenon. This suppression was not exceeded by the addition of 10(-4) M preparations of corticosteroids and was statistically the same as that induced by a combination of both corticosteroids and MAM. The addition of PGE2 alone and in combination with methylprednisolone also failed to affect [3H]thymidine incorporation by committed lymphocytes.

Adrenal Cortex Hormones↗