Search PubMed⌕ Search

Biomedical subjects

J M Decker

Publications and source records attributed to J M Decker.

51 records · Page 3Linked to original sources
PubMed1977

Lymphocyte-like cells of the tunicate, Pyura stolonifera: binding of lectins, morphological and functional studies.

In vitro investigations were carried out to determine whether lymphocyte-like (small round) cells of the tunicate Pyura stolonifera react to allogeneic cells and mitogens in a manner comparable to that of vertebrate immunocytes. The lymphocyte-like cells possessed receptors for concanavalin A, wheat germ agglutinin and soybean lectin as shown by binding of radioiodinated lectins in scintillation counting and autoradiographic assays. This binding did not induce mitogenesis. Mixtures of cells of P. stolonifera individuals taken from the same or distinct localities did not show enhanced DNA synthesis when assayed at time intervals ranging from 3 to 10 days. The small round cells of this and other tunicates are not completely similar to vertebrate lymphocytes in morphology. Our observations support the concept that these cells are not directly homologous to immunologically competent vertebrate lymphocytes, but may serve as haemopoietic stem cells as proposed by other (Endean, 1954; Freeman, 1970).

Animals↗
PubMed1977

Spontaneous cytotoxicity of human peripheral blood mononuclear cells toward red blood cell targets. II. Time-dependent loss of suppressor cell activity.

In a previous paper we demonstrated that human peripheral blood mononuclear cells become strikingly cytotoxic toward a wide variety of red blood cell targets after 7 days of in vitro culture. The cell responsible for cytotoxicity does not rosette with SRBC and demonstrates both surface adherence and phagocytic properties. In this paper we wish to show that development of spontaneous cytotoxicity is due to a time-dependent loss of suppressor cell function. Fresh autologous lymphocytes, when added to cultured cells, abrogate the subsequent expression of spontaneous cytotoxicity toward RBC targets. The suppressor cell is radioresistant; requires 24 hr to suppress optimally; is inactivated by heating at 56 degrees C for 15 min, and is enriched in the non-T interface after SRBC rosette depletion over a discontinuous Ficoll-Hypaque gradient. Furthermore, the addition of a cell-free sonicate of fresh lymphocytes is capable of inhibiting spontaneous cytotoxicity toward RBC targets. However, if mononuclear cells are allowed to incubate in tissue culture medium for 7 days they are no longer suppressive after sonication. These data suggest that fresh mononuclear cells exert a potent negative regulatory influence on monocyte killing. Our culture conditions by removing this negative influence have produced a new model of spontaneous nonspecific killing by monocytes.

Antigens↗
PubMed1976

Evolutionary and developmental aspects of T-cell recognition.

Studies relating to the nature of the antigen-specific T-cell receptor are reviewed in the light of present knowledge of phylogenetic and ontogenetic development. It is suggested that this evidence supports the concept that immunoglobulin (Ig) is the T-cell receptor, and that the following conclusions may be tentatively drawn.

Aging↗
PubMedDate not supplied

Uromodulin: a specific inhibitor of IL-1-initiated human T cell colony formation.

Uromodulin, an 85 kDa naturally occurring immunosuppressant, was found to selectively and specifically inhibit the ability of IL-1 to induce colony responses by highly enriched suspensions of PHA-stimulated T lymphocytes. Dilutions of 1 x 10(-8) M completely blocked the colony growth of T lymphocytes cultured with 50 U/ml IL-1; 1 x 10(-9) M dilutions reduced scores by 83%. By contrast, uromodulin did not inhibit the responses of unseparated mononuclear cells, isolated T lymphocytes cultured with irradiated adherent cells, or stimulated T cells whose growth was initiated by either IL-2 or a soluble factor derived from Raji cells.

Colony-Forming Units Assay↗
PubMedDate not supplied

Mechanism of inhibition of natural killing by a glycopeptide isolated from the K562 plasma membrane.

The mechanism of lysis by cytotoxic T lymphocytes, K cells, and natural killer (NK) cells is imperfectly understood at this point. In this report, material (glycopeptide) isolated from the plasma membranes of K562 cells and fractionated on lectin affinity adsorbents which has been shown to inhibit NK lysis, was used in several specific NK assays to ascertain what stages of the NK-lytic sequence is inhibited by this substance. Results indicate that this glycopeptide (a) does not inhibit initial binding, but dissociates conjugates following initial effector target interactions; (b) inhibits NK lysis beyond Ca-dependent programming, and (c) inhibits lysis induced by NK cell-derived soluble cytotoxic factors (NKCF) in a soluble factor assay. These results suggest that this glycopeptide can effect the lethal hit stage of NK lysis and may represent structures which can associate directly with NKCF.

Binding, Competitive↗