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Biomedical subjects

C E Hayes

Publications and source records attributed to C E Hayes.

At least 91 records · Page 5Linked to original sources
PubMed1984

I-A-controlled T cell molecules: protease sensitivity.

An I-A subregion-controlled structure (I-At) characterizes some helper T cells and augmenting factors. This epitope is associated with a glycoprotein. Extended trypsin digestion removed the determinant; tunicamycin blocked its reexpression. In contrast, limited trypsinization increased the number of I-At-bearing peripheral T cells from 17 to 35%. The I-At molecule density on cells expressing this structure did not change measurably with limited enzyme treatment. Rather, some previously negative T cells (20%) expressed the epitope after mild proteolysis. A third T cell subset (60%) expressed no I-At molecules regardless of enzyme treatment. We conclude that the I-At molecule is shielded by trypsin-labile material on some T cells, whereas on others it is fully exposed. The transition from a shielded to an exposed configuration may correlate with T cell activation. Cycloheximide inhibited the biosynthesis of both the I-At molecule and the shielding substance by T cells. Unlike I-A-controlled T cell structures, B cell I-A-encoded molecules are neither shielded nor trypsin labile. The relationship between I region-controlled T cell and B cell molecules is discussed.

Animals↗
PubMed1983

Enhancement of murine T cell I-J expression by limited proteolysis.

I-J-encoded structures on peripheral T cells and thymocytes appear normally to be blocked or shielded by material that is susceptible to proteolysis. Limited proteolysis with trypsin, papain, pronase, or chymotrypsin increased the number of peripheral T cells and thymocytes lysed by anti-I-Jk serum and complement. Proteolysis did not induce I-Jk expression on B cells or on negative strain T cells. Increased lysis was enzyme concentration and time dependent and was not due to increased susceptibility of protease-treated cells to lysis by antibody plus complement; proteolysis rendered T cells and thymocytes less susceptible to lysis by anti-H-2Kk, anti-H-2Dd, and anti-Lyt-2 antibodies. Absorption experiments showed that I-Jk determinant density was increased in the protease-treated T cell population. The I-Jk determinants detected are proteins or glycoproteins; extended proteolysis removed these molecules from the T cell surface. Treatment of T cells or thymocytes with activated macrophage culture supernatant containing proteolytic activity produced a small but reproducible increase in I-Jk expression. Proteolysis of lymphocyte membranes, possibly mediated by macrophages, may have a role in cellular differentiation and immune activation.

Animals↗
PubMed1982

Lung water quantitation by nuclear magnetic resonance imaging.

Nuclear magnetic resonance imaging was used to determine quantitatively the water distribution of saline-filled and normal rat lungs in both isolated lung and in situ preparations. Regional lung edema was easily detected. Studies of an isolated lung fragment indicate an accuracy of better than 1 percent and images of H2O/D2O phantoms indicate an average error of 2.7 percent.

Animals↗
PubMed1982

Murine T cell-specific Ia antigens: monoclonal antibodies define an I-A-encoded T lymphocyte structure.

T lymphocytes express a unique I-A subregion-controlled surface molecule that is not expressed on B lymphocytes. We produced antisera and monoclonal antibodies recognizing this structure. Exhaustive B cell adsorption (A.TH X B10.HTT)F antiserum, produced against activated A.TL T cells, left antibodies that bind an I-Ak specificity on some B10.A(4R) T lymphocytes (11 +/- 2%, mean +/- SEM). Similarly, exhaustive B cell adsorption of (A/J X B10.MBR)F antiserum, produced against activated B10.A(5R) cells, left antibodies specific for an I-Ab determinant on B10.A(5R)T cells (17 +/- 2%). We fused A.TL-immune (A.TH X B10.HTT)F splenocytes with NS-1 myeloma cells and identified antibody-producing hybrid cells by a fluorescent enzyme-linked immunosorbent microassay described herein. Eight monoclonal antibodies were selected; these lyse 7--26% of peripheral T cells from I-Ak strains. Thymocytes and bone marrow cells do not express the I-Ak T cells determinant. Exhaustive B cell adsorption did not remove I-Ak T cell-specific monoclonal antibodies.

Animals↗
PubMed1980

Generation of primary cytotoxic lymphocytes against non-major histocompatibility complex antigens by anti-Ia serum plus complement-treated lymphocytes.

The results presented in this paper demonstrate that responding cells that remain after anti-Ia serum plus complement (C) treatment generate a highly significant in vitro cytotoxic response against minor histocompatibility complex antigens. The cytotoxic response appears to be antigen specific in that target cells of strains other than the sensitizing strain are not lysed, or lysed to a lesser extent. The cytotoxic cells are susceptible to anti-Thy-1 plus C lysis. Anti-Ia serum may function by removing an unprimed suppressor cell, although other mechanisms cannot be ruled out.

Animals↗
PubMed1980

I-N: a newly described H-2 I subregion between K and I-A.

Strong, primary mixed leukocyte culture-proliferative responses in certain K region-incompatible strain combinations led us to consider whether an I region-like locus might exist between K and I-A. Results obtained with an (A. TL X B10.D2)F1 anti-B10.BR serum provided serological evidence for a new locus; B10.T(6R)-absorbed serum retained reactivity on AQR lymphocytes. This finding demonstrates an antigen, Ia.W41, encoded by a locus, Ia-7, within a new I subregion, I-N.

Animals↗
PubMed1980

Murine T cell Ia antigens: specificity Iat.46 maps in I-J to I-E chromosomal segment of H-2 complex.

An alloantiserum was prepared in C57BL/10 mice hyperimmunized with concanavalin A-stimulated B10.HTG thymocytes. Absorption with separated B10.A(3R)B and T lymphocytes, followed by titration on these cell types, revealed a new I-region controlled T-cell specificity, Iat.46. The determinant is present on a subpopulation of mature peripheral T cells but not on B lymphocytes, thymocytes, or bone marrow cells. It is also observed using (A.TH X B10.HTT)F1 anti-A.TL antiserum on B10.A(3R) T lymphocytes. The k and d haplotypes are fully crossreactive with regard to Iat.46 expression. B10.HTT, C57BL/10, and BSVS do not carry the Iat.46-encoding allele. Moreover, Iat.46 is not a determinant formed by I-A--I-E gene complementation. The Iat.46-controlling gene, Ia-8, may be positioned to the left of the B10.HTT crossover and to the right of the B10.A(3R) recombinational event. Thus, this determinant may be considered either to represent complexity within the I-J subregion or to demarcate a new I subregion between I-J and I-E.

Animals↗
PubMed1978

T-cell-specific murine Ia antigens: serology of I-J and I-E subregion specificities.

(B10 X B10.D2)F1 mice were immunized with B10.A(5R) concanavalin A-stimulated thymocyte blasts. The genetic disparity between donor and recipient was restricted to the I-J and I-E subregions of the murine major histocompatibility (H-2) complex. A high-titered, T-cell-specific anti I-JkEk serum was obtained. The antiserum lysed 27-30% of haplotype k, q, or s lymph node cells, 5.3 +/- 2% of haplotype k spleen cells, and did not lyse thymocytes. Nylon wool-passed lymph node or spleen cells (H-2k) showed considerable reactivity with anti-I-JkEk serum (35-40% lysis); anti-Thy1.2 plus complement-treated spleen cells did not react (less than 5% lysis). I-Ek antibody was detected by B10.A(3R) lymph node cell reactivity (20% lysis), whereas reaction with H-2k lymph node cells after B10.A(3R) absorption demonstrated IJk antibody (12% lysis). Lymphocyte activation with alloantigen or mitogen led to increased anti-I-JkEk serum reactivity. These results, showing antibody production to at least two T-cell Ia antigenic determinants by concanavalin A thmocyte blast immunization, suggest that a group of I-region-encoded T-cell specificities may not have been detected using conventional immunization protocols because they would not have comprised a major antigenic component of the immunizing cell population. The existence of multiple Ia antigenic determinants unique to T lymphocytes would have important implications for serological and functional studies of T-cell subpopulations.

Animals↗
PubMed1976

Carbohydrate-binding properties of an immobilized alpha-D-galactopyranosyl-binding protein (lectin) from the seeds of Bandeiraea simplicifolia.

The alpha-D-galactopyranosyl-binding lectin from Bandeiraea simplicifolia has been coupled to cyanogen bromide-activated Sepharose 4B. Using this immobilized system, we have been able to study the interaction of the lectin with model carbohydrate-protein conjugates and polysaccharides, and to reaffirm this protein's carbohydrate-binding specificity. The opportunity for the isolation of biopolymers containing alpha-D-galactopyranosyl end-groups is demonstrated by the single-step purification of a new galactomannan from the seeds of Cassia alata.

Binding Sites↗
PubMed1975

Equilibrium dialysis and cell binding studies on Bandeiraea simplicifolia lectin.

Equilibrium dialysis studies on the binding of the blood group B-specific Bandeiraea simplicifolia lectin to methyl alpha-D-galactopyranoside demonstrated the existence of one carbohydrate binding site per subunit for the tetrameric protein, with an intrinsic association constant of 8.6 x 10(4) (M) (-1) at 2 degrees and 3.3 x 10(4) (M)(-1) at 20 degrees. These values correspond to a free energy of binding, ΔG(0') (pH 7.2), of -6.21 kcal/mol and-6.06 kcal/mol at 2 degrees and 20 degrees, respectively. The sites appeared homogeneous and noninteracting. B. simplicifolia lectin receptor sites per human B erythrocyte varied from 0.72 x 10(5) to 1.34 x 10(5) with an apparent association constant of 1.1 x 10(7) (M)(-1) to 2.9 x 10(7) (M)(-l). The binding characteristics of B. simplicifolia lectin are compared to other purified lectins.

ABO Blood-Group System↗
PubMedDate not supplied

MR imaging of the pelvis with an endorectal-external multicoil array.

Magnetic resonance (MR) images of the pelvis obtained with an endorectal coil have improved resolution relative to that of body coil images; however, they have limited spatial coverage. The sensitivity profile can be improved by using the endorectal coil combined with an external anterior coil as part of a multicoil array. If each coil is connected to a separate receiver, the individual images can be combined to provide an optimal signal-to-noise ratio (S/N). The authors have investigated a 5-inch (12.7-cm) surface coil or a two-coil array as the anterior coil. In both of these configurations, the S/N is improved relative to that of the endorectal coil alone at distances greater than 3 cm from the endorectal coil. The anterior two-coil array provides more lateral coverage. The improved spatial coverage available with this technique expands potential clinical applications of endorectal MR imaging.

Female↗