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R E Cone

Publications and source records attributed to R E Cone.

At least 73 records · Page 4Linked to original sources
PubMed1983

Analysis of normal and neoplastic lymphocyte surface-labeled proteins by two-dimensional polyacrylamide gel electrophoresis.

Normal and neoplastic murine and human lymphocytes were surface-labeled by lactoperoxidase-catalyzed radioiodination, and the cell lysates were subjected to two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) analyses, combining isoelectric focusing in the first dimension and sodium dodecyl sulfate-PAGE (SDS-PAGE) in the second dimension. 2D-PAGE autoradiogram patterns were reproducible and reflected differences in cell types. A string of spots with a Mr of 100K was tentatively identified as a new T-cell marker (Tp100) which was present in all murine and human T cells examined including human T lymphomas. Murine and human B cells displayed markers characteristic to B cells of each species with some similarities between them. Human lymphomas and murine cell lines showed markers which were absent or only weakly visible in normal cells. Thus, 2D-PAGE analysis of lymphocyte surface proteins proved to be a method useful for searching for various markers.

Animals↗
PubMed1983

Heterologous antisera to Lyt-1+, 2- -derived antigen-binding factor detect a subfactor of an antigen-specific suppressor factor and cell surface proteins on Lyt-1+, 2- and Lyt-1-, 2+ T cells.

Rabbits were immunized with TNP-specific Lyt-1+, 2- T cell-derived, antigen-binding proteins (PCI-F) released by T cells sensitized by skin painting with picrylchloride. The resulting antiserum (anti-PCI-F) bound to PCI-F and TNP-specific factors that suppressed delayed hypersensitivity (TSF) known to be comprised of PCI-F and Lyt-2+ -derived polypeptides released by cells sensitized by injection of trinitrobenzenesulfonic acid (TNBSF). Anti-PCI-F bound to T lymphocytes and 68,000 to 72,000 m.w. T cell surface proteins but not B cells on their surface proteins. Anti-PCI-F bound to both Lyt-1+ and Lyt-2+ T cells and surface proteins. A comparison of anti-PCI-F with anti-TSF indicates that anti-TSF contains specificity for Ly-2+ T cell-derived components of TSF and T cells not present in anti-PCI-F. The possibility of multiple isotypes of T cell receptors and antigen-binding molecules is discussed.

Animals↗
PubMed1983

Purification and characterization of TNP-specific immunoregulatory molecules produced by T cells sensitized by picrylchloride (PC1F).

T cell-derived TNP-specific factors associated with immunoregulatory activity were obtained by culture of T cells obtained from mice sensitized by skin-painting with picrylchloride. Culture medium was absorbed to TNP-Sepharose and TNP binding proteins were prepared by elution with TNP. The hapten affinity-purified proteins were characterized by size and charge and were found to be acidic 70,000 m.w. polypeptides that occur as monomers or oligomers. Oligomeric proteins interact with factors produced by mice injected with trinitrobenzenesulfonic acid to form factors that suppress specifically the ability of TNP-sensitized T cells to transfer contact sensitivity to TNP. Monomeric (no more than 70,000 m.w.) molecules do not form suppressor factors but can transfer contact sensitivity to TNP. Moreover, reduction and alkylation of oligomeric molecules inactivates their suppressor activity but causes them to be able to transfer contact sensitivity. The results suggest that T cell-derived antigen-specific molecules may have different effector functions dependent on their oligomeric state.

Animals↗
PubMed1982

Absorption of shed I-Ak and H-2Kk antigens by lymphoid cells.

The fate of cell surface I-Ak and H-2Kk antigens shed by murine spleen cells in culture was studied by incubation of nonlabeled spleen cells or splenic T or B cells with culture fluids containing shed radiolabeled alloantigens. Approximately 30 to 40% of the shed alloantigens could be absorbed by syngeneic or allogeneic murine T cells, B cells, or macrophages, but not by heterologous erythrocytes of human peripheral blood lymphocytes. Absorption was dependent on temperature and lipids associated with the shed glycoproteins. Once absorbed, the alloantigens were catabolized by the absorbing cells with a half-life of approximately 4 hr. It is suggested that absorption of shed cell surface alloantigens may be a vehicle for intercellular communication in the immune system.

Absorption↗
PubMed1981

Regulation of murine B lymphocyte plasma membrane protein turnover and shedding.

Lactoperoxidase-catalyzed cell surface radioiodination was employed to radiolabel murine splenic B-cell membrane immunoglobulins (IgM and IgD) and alloantigens encoded by the Major Histocompatibility Complex (I-Ak, I-Ek, H-2Kk, H-2Dk). The fate of the radiolabeled proteins was monitored by in vitro culture of labeled cells and isolation of labeled antigens from detergent lysates of the cells or culture fluids obtained at different times during culture. The effects of temperature, antimetabolites, colchicine, and cytochalasins on membrane protein catabolism demonstrated heterogeneity in rate, energy dependence, and cytoskeletal control of turnover suggesting that functional domains of turnover control exist in the B lymphocyte membrane.

Animals↗
PubMed1981

Characterization of T-cell surface proteins bound by heterologous antisera to antigen-specific T-cell products.

Heterologous antisera specific for murine T-cell antigen-recognition molecules were prepared by immunization of rabbits with dinitrophenyl-specific murine T-cell suppressor factors that had been purified by hapten-affinity chromatography. The antisera (i) bind to antigen-specific T-cell products that differ in their antigen-recognizing specificity; (ii) absorb the specific suppressor activity in preparations containing suppressor factors; (iii) stain all Lyt2+ T cells brightly in indirect immunofluorescence examination, stain some Lyt1+ cells (with low intensity), and do not stain B cells; (iv) precipitate cell membrane proteins from T cells that bear striking structural resemblance to the antigen-specific molecules used for immunization. These results suggest that, like B cells, there is a commonality between antigen-specific effector molecules released by T cells and their membrane-associated receptors.

Animals↗
PubMed1981

Detection of T cells that secrete molecules which share determinants with antigen-specific T-cell factors.

A single-cell secretion assay was used to detect cells that secrete products which react with an antiserum that binds T cell antigen-binding polypeptides. The antiserum (R11), which was produced by immunization of rabbits with a murine trinitrophenyl-specific suppressor factor, reacts with T cells and their products and with a suppressor T-cell clone but not with B cells or their products. The secretory cells this antiserum detected were found to be unevenly distributed among various organs (spleen, lymph node, and thymus) and, to different degrees, in spleens of various strains of mice. In unimmunized CBA/J mice, approximately 1-3% of spleen cells secreted macromolecules precipitable by R11. The majority of the secretory cells could be removed by panning with a mixture of Ly 1 and Ly 2 antibodies but not with either antibody alone. This is consistent with the cells having low surface antigen densities as a result of being either "pre-T" cells or mature secretory cells analogous to B-lineage plasma cells. In agreement with the latter possibility was our finding that the secretory activity of cells detected with antisuppressor factor was comparable to that of Ig-secretory cells as detected with an anti-Ig antiserum. However, higher numbers of R11+ secretory cells were seen in the immunoglobulin-negative fraction of spleen cells from nude mice, which could be interpreted to favor the first possibility. In either case this study shows that the single-cell assay technique is well suited for the detection and characterization of molecules released by immunoregulatory T cells.

Animals↗
PubMed1981

Isolation and partial characterization of an antigen-specific T-cell factor associated with the suppression of delayed type hypersensitivity.

Antigen-specific factors associated with immunosuppressive activity, released by cultured T cells from mice tolerant to the haptens trinitrophenyl, dinitrophenyl and oxazolone, were purified by hapten affinity chromatography. Their binding specificity for antigens paralleled their immunoregulatory activity. Like some immunoglobulin molecules, these factors had blocked NH2 termini and could be bound to Fc-like receptors on macrophages. However, neither immunoglobulin constant region determinants (isotypes) nor antigens encoded by the major histocompatibility complex were detected on the suppressive factors. The purified factors occurred as 68,000-dalton proteins and non-covalently linked dimers. No associated immunoglobulin light chain molecules were detected. The factors showed a marked propensity toward degradation with major breakdown products of 45,000-50,000 and 25,000-30,000 daltons. These results suggest that these molecules are the T-cell products analogous to B-cell immunoglobulin (equivalent to heavy chains) and that they may be the antigen-specific components which act in conjunction with major histocompatibility-controlled gene products to perform antigen-specific suppression.

Animals↗
PubMed1981

I-Kk and H-2Kk antigens are shed as supramolecular particles in association with membrane lipids.

The form of 125I-labeled membrane alloantigens (I-Ak and H-2Kk) and immunoglobulin M shed by murine splenic lymphocytes labeled by lactoperoxidase-catalyzed radioiodination was determined by gel chromatography and ultracentrifugation. I-Ak and H-2Kk antigens are shed as particles ranging in size from 3 X 10(5) to 2 X 10(6), whereas membrane IgM is shed as an individual unit consonant with its native size of 180,000. The effects of detergents on the size of shed I-Ak and H-2Kk and the coprecipitation of (3H) lipids with these proteins suggest that I-Ak and H-2Kk are shed in association with local membrane lipids as small membrane-derived vesicles, whereas membrane IgM is shed without detectable associated lipid.

Animals↗
PubMed1980

Selective turnover and shedding of H-2K and H-2D antigens is controlled by the major histocompatibility complex. Implications for H-2-restricted recognition.

Lactoperoxidase-catalyzed cell surface radioiodination and incorporation of [3H]-leucine were employed to radiolabel H-2K and H-2D antigens of murine spleen cells. The fate of H-2 antigens was monitored by in vitro culture of labeled cells and isolation of labeled antigens from detergent lysates of the cells and culture supernates obtained at different times during culture. H-2Kk antigens were found to be rapidly turned over and shed by CBA/J cells, whereas the turnover of H-2Dk antigens was extremely slow. Analysis of the membrane residence times of surface-labeled H-2K and H-2D antigens on spleen cells from various H-2-congenic and -recombinant strains demonstrated variations in the shedding rates of H-2K and H-2D antigens, which were controlled by genes mapping in the major histocompatibility complex. These variations show a striking correlation with published, genetically controlled quantitative variations in the cytotoxic response of T lymphocytes to chemically modified or virus-infected syngeneic cells.

Animals↗
PubMed1980

Ia antigen turnover. II. The kinetics of biosynthesis and release of Ia alpha- and beta-chains by murine spleen cells in culture.

The kinetics of biosynthesis, release, and turnover of Ia antigens were determined by 3H-leucine labeling, immunoprecipitation and SDS-PAGE analysis. Continuous incorporation and pulse-chase experiments demonstrated that the half-life of the total cell Ia pool was 8 hr, with radiolabeled Ia antigens released from the cell within 4 hr of culture initiation. Both Ia alpha- and beta-chains were released by the cells. I-A antigen turnover was more rapid than I-E antigen turnover. However, detailed comparison of I-A and I-E alpha- and beta-chain biosynthesis demonstrated that the E beta (Ae) chains were synthesized more rapidly than E alpha chains, at rates similar to A alpha- and A beta-chains. Once assembled, however, E alpha- and E beta (Ae)- chains were turned over at the same rate. This kinetic anomaly may reflect post-translational association of polypeptides coded by separate genes into complete I-E antigens.

Animals↗
PubMed1979

Differential effects of colchicine and cytochalasins on the shedding of murine B cell membrane IgM and IgD.

Lactoperoxidase (EC 1.11.1.7) catalyzed cell surface radioiodination was employed to monitor the fate of murine B cell membrane (mem) IgM and IgD on radiolabeled cells in short-term culture. Both mem-IgM and mem-IgD were shed from the cell surface with biphasic kinetics. The rapid phase of mem-IgD shedding was somewhat slower (half-time = 12 hr) than that of mem-IgM shedding (half-time = 7-8 hr). The effect of temperature, colchicine, and cytochalasin on the shedding of the two membrane immunoglobulin isotypes was determined. The shedding of mem-IgD was more energy dependent than that of mem-IgM and was sensitive to colchicine but not cytochalasin. Conversely, the shedding of mem-IgM was sensitive to cytochalasin but not colchicine. The results suggest that the mechanisms of shedding of mem-IgM and mem-IgD are qualitatively distinct and may be regulated by microfilaments or microtubules, respectively.

Animals↗