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D T Yu

Publications and source records attributed to D T Yu.

70 records · Page 4Linked to original sources
PubMed1975

Effect of polycations and polyanions on behavior of sheep red blood cell rosettes of human lymphocytes.

The role of cell surface charges in the behavior of sheep red blood cells (SRBC) rosettes with human lymphocytes was investigated by using various polycations and polyanions. Polycations (DEAE-dextran, polybrene, poly-L-lysine, spermadine) at appropriate concentrations (1) invariably increased the proportions of early rosettes. This was so irrespective of whether it was the SRBC or the lymphocytes that were being treated with the reagents. (2) The rosettes so formed also consisted of a greater number of red blood cells per rosette (3). On incubating the rosettes at 37 degrees C, they dissociated by capping. The rates of dissociation and capping were retarded by polycation treatment. (4) The resistance to rosette disruption was increased. These properties were very similar to those observed on cells treated with neuraminidase. Treatment of cells with the polyanions heparin and dextran sulfate induced the opposite effects: reduced the number of rosettes and increased the rate of dissociation, and decreased the resistance of rosettes to disruption. It was concluded that alterations of cell surface charges could drastically influence SRBC-lymphocyte interactions. To investigate whether rosette inhibitors could do so by altering cell surface charges, cell were treated with anti-lymphocytic sera, 2,4-dinitrophenol and sodium azide. All three agents inhibited rosette formation. Whereas DEAE-dextran could partially reverse the inhibition by the first two agents, it failed to do so with the third. This suggested that the first two may have inhibited rosette formation by altering the surface charges.

Animals↗
PubMedDate not supplied

Lymphocyte involvement in rheumatoid arthritis. Studies during thoracic duct drainage.

Grip strength, ring size, duration of morning stiffness, and the number of tender joints improved significantly in 9 patients with severe rheumatoid arthritis during prolonged continuous removal of thoracic duct lymphocytes through a surgical fistula. There was no improvement in 4 subjects in whom surgery failed to establish satisfactory lymph drainage. Reinfusion of unlabeled or 51Cr-labeled autologous lymphocytes resulted in transient exacerbation of disease activity in 3 subjects. Following reinfusion, some 51Cr-labeled lymphocytes could be found in the inflamed synovium and synovial fluid by autoradiography, and radioactivity was detected over the joints by surface counting of gamma radiation. Active rheumatoid arthritis recurred in all subjects at variable intervals after cessation of lymph drainage. These findings are compatible with the hypothesis that some of the lymphocytes in the thoracic duct lymph are essential for the continued activity of the inflammation associated with rheumatoid arthritis.

Adult↗
PubMedDate not supplied

Epitope analysis of an HLA-B27-derived synthetic peptide: a possible approach to analyzing HLA class I antigens.

A monoclonal antibody, F3H7, was generated by immunizing mice with a synthetic peptide corresponding to residues 63-84 of the B*2705 allele of the HLA-B27 antigens. The reactive epitope and the contact residues on the peptide were localized by ELISA using a large panel of overlapping peptides as well as peptides with substituted amino acids. Residues corresponding to R75, D77 and L78 on the HLA-B27 protein appeared to be critical. The clarity of these results indicate that this is a potentially useful approach to the study of HLA class I epitopes.

Alleles↗
PubMedDate not supplied

A monoclonal anti-HLA-B27 antibody which is reactive with a linear sequence of the HLA-B27 protein is useful for the study of molecular mimicry.

In the search for cross-reactivity between bacteria and HLA-B27, three groups of investigators have identified several bacterial envelope proteins which are reactive with the monoclonal anti-HLA-B27 antibodies B27.M1 and B27.M2. Since these two antibodies react poorly with HLA-B27-derived synthetic peptides, it is not possible to locate the reactive epitopes on the HLA-B27 using synthetic peptides. Here, we introduce Ye-2, a monoclonal anti-HLA-B27 antibody which, unlike B27.M1 and B27.M2, is reactive with a synthetic peptide derived from residues 63-84 of HLA-B27.1. Analysis with a cross-reactive peptide derived from residues 226-244 of bovine carbonic anhydrase suggests that only a few of the amino acid residues in the HLA-B27-derived peptide are responsible for the reactivity. This antibody should be a useful adjunct in a preliminary assessment of whether a bacterial protein mimics HLA-B27 in primary structure.

Amino Acid Sequence↗
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↗