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Biomedical subjects

I Gery

Publications and source records attributed to I Gery.

At least 163 records · Page 9Linked to original sources
PubMed1979

Stimulation of keratocyte metabolism by products of lymphoid cells.

Products of leukocytes were found to activate cultures of keratocytes, manifested by the increased incorporation of thymidine or leucine. The keratocyte activation capacity crosses the species barriers between rabbit, monkey, and human. The level of secreted keratocyte-activating factor(s) (KAF) depends on the stimulation of the leukocytes. Thus unstimulated rabbit leukocytes produced very little or no KAF, whereas significant levels were produced by leukocytes stimulated with lipopolysaccharide (LPS) or concanavalin A. High levels of KAF were also found in supernatants of human mononuclear leukocytes stimulated by LPS. The effects of the activated leukocyte supernatants on keratocyte metabolism resembled the increased metabolic activity induced by the fibroblast and epidermal growth factors. The relationship between KAF and a possible modulating role of the products of lymphoid cells on corneal wound healing is suggested.

Animals↗
PubMed1978

Mononuclear phagocytes from carrageenan-induce granulomas. Isolation, cultivation, and characterization.

Stable cultures of mononuclear phagocytes from carrageenan-induced granulomas in mice have been established after enzymatic dispersion of these lesions. The cells can be maintained for up to 3 wk without division in serum-free media. The mononuclear phagocytes were identified by several criteria. The cells are adherent, phagocytic, contain lysosomal acid hydrolases at high specific activities, secrete lysozyme, and bind soluble aggregates of IgG. The activities of 5'-nucleotidase and leucine aminopeptidase in the cultured granuloma cells showed that they resembled macrophages from thioglycollate-stimulated mice but not unstimulated macrophages in these respects. Supernates from the cultured granuloma cells contain factor(s) which induce the proliferation of thymocytes; the release of such factors by the cells is stimulated by lipopolysaccharide.

Acid Phosphatase↗
PubMed1977

Selective accumulation of cells with 'B' properties in stimulated lymph nodes.

Draining lymph nodes from mice which had been stimulated with bacterial adjuvants or the skin sensitizing agent, oxazolone, showed a marked increase in cell content, presumably due to lymphocyte immigration. A surprisingly large proportion of these cells exhibit properties of B lymphocytes: the presence of surface Ig, lack of Thy-1-like antigen and responsiveness to lopopolysaccharide (LPS). The relationship between the presence of surface markerand responses to class-specific mitogens, of cells from the stimulated nodes, was established by testing fractionated lymphocyte populations. Enriched T cells did not react to LPS, whereas removal of cells with Thy-1 antigen by specific antisera eliminated the reactions to T mitogens but had little or no effect on the LPS response. The data thus suggest that B cells, which make up a small portion of the circulating lymphocyte pool, are selectively accumulated in lymph nodes stimulated by different immunogens, including T-specific stimulants. This interpretation contradicts the generally accepted assumption, that stimulat lymph nodes trap mostly T lymphocytes.

Animals↗
PubMed1976

Altered surface morphology of Concanavalin A transformed thymic lymphocytes as seen by scanning electron microscopy.

The present study records the surface architecture of normal and Concanavalin A transformed thymic lymphocytes as seen under the scanning electron microscope, employing different modes of cell preparation and fixation. Murine thymic lymphocytes have a relatively uniform surface architecture and display few microvilli, irrespective of the mode of fixation used in their preparation for SEM. When cells are incubated for 72 hours no gross changes in surface morphology are noted. After incubation with Concanavalin A for 72 hours the transformed cells display multiple microvilli and are easily distinguished from their relatively smooth normal non-transformed counterparts. The results are reviewed in the light of current knowledge on the surface architecture of lymphocytes and the factors influencing lymphocyte surface topography are discussed.

Animals↗
PubMed1976

Effects of in vivo administered B. pertussis and other adjuvants on the mitotic responses of lymphocytes in vitro.

Intraperitoneal treatment of mice with adjuvants affects the in vitro response of their lymphocytes toward class-specific mitogen. Spleen cells from animals injected with Corynebacterium parvum organisms showed in some cases an increase in their response to all mitogens, while in other experiments, a moderate decrease in the reaction to T-specific mitogens (concanavalin A and phytohemagglutinin) was found. Injection of lipopolysaccharide (LPS) and in particular Bordetella pertussis bacteria, brought about a marked reduction in the response of spleen cells to B mitogens (LPS and PPD) but had little or no effect on the reaction to the T mitogens. Intraperitoneal administration of B. pertussis caused a marked depletion of lymph nodes and a high level of lymphocytosis. Blood cells of the treated mice showed an increased response to T mitogens, whereas mesenterial lymph node cultures reacted higher than the controls to LPS and without stimulation. No change was noted in the responses of cells from the axillary lymph nodes of these pertussis-treated mice.

Adjuvants, Immunologic↗
PubMed1976

Antigenic properties of subsets of splenic T lymphocytes responding to lectins.

The aim of the present study was to characterize the antigenic properties of spleen cells responding in vitro to various mitogenic stimuli. Mouse spleen cells were treated with alloantibodies and C and then cultured with various concentrations of lectins. The exposure of spleen cells to various dilutions of either anti-theta serum and C or anti-Ly serum and C inhibited the response to optimal concentrations of PHA to a greater extent than the response to optimal concentrations of Con A. With the exception of the optimal lectin concentration, theta-antiserum and C had a stronger inhibitory effect on the response to Con A than to PHA. The exposure of spleen cells to H-2 antiserum and C inhibited their response to Con A to a greater extent than to PHA. The inhibitory activity of H-2 antiserum and C was inversely correlated with the dose of PHA used for stimulation. The lower the concentration of PHA used for stimulation the more effective was the inhibitory effect of the antiserum. The inhibitory effect of H-2 antiserum and C on the response to Con A was highest at optimal concentrations of the mitogen, and somewhat less pronounced above or below this concentration. The present study suggests that subsets of splenic T-cells that react to various concentrations of mitogens, differ in their theta- and H-2 alloantigenicity.

Animals↗
PubMed1976

The reactivity of spleen cells from malarious rats to non-specific mitogens.

The reaction of spleen cells from rats infected with Plasmodium berghei to non-specific mitogens has been measured. The cells have been stimulated in vitro by phytohaemagglutinin, concanavalin-A and by bacterial lypopolysaccharide. In addition the release of lymphocyte activating factor (LAF) by splenic macrophages has been assayed using a heterologous thymocyte culture. The reactivity of spleen lymphocytes from malarious rats is severly affected. The cells do not react either to the T cell-specific mitogens or to the B-cell stimulant. The reactivity of macrophages, as measured by the release of LAF, was not altered by the disease.

Animals↗
PubMed1975

The nature and function of T-cell antigens.

T-lymphocytes differ antigenically from B-lymphocytes. In the present study attempts were made to determine the role of surface antigens of T-cells, in their migration in vivo and in their response to mitogens. Exposure of thymus cells to anti-H2 sera inhibits migration to the lymph nodes (LN) to a greater extent than to the spleen. Fab fragments of H-2 antisera had only a slight effect on lymphocyte migration, inhibiting the LN-seeking stream only slightly more than the spleen-seeking stream. The interaction of Con-A with carbohydrates on the cell-surface of lymphocytes inhibits preferentially their localization in LN. Studies on the migration of lymphocytes that had localized either in the LN or spleens of primary host indicate that Con-A does not eliminate LN-seeking cells, but rather inhibits their active localization in LN. The subpopulation of lymphocytes, in both thymus and spleen that responds to Con-A was found to possess a higher H-2 antigenicity and a lower Ly and theta-antigenicity than the cells responding to PHA. Spleen cells responding to low concentrations of PHA had a relatively high H-2 antigenicity, whereas thos responding to high concentrations of PHA had a low H-2 antigenicity. Exposure of thymus cells to H-2 antiserum alone markedly inhibited their response to Con-A. Similar treatment of spleen cells had only a weak inhibitory effect.

Animals↗
PubMed1975

Subpopulations of mouse spleen lymphocytes. II. Immunological reactivity of spleen cells fractionated on BSA density gradients.

We found in previous experiments that fractionation of non-immune mouse spleen cells on bovine serum albumin density gradients yields two subpopulations of T cells, one of high, the other of low density. Both subopopulations could be stimulated in corporate thymidine by the T cell-specific mitogen concanavalin A (con A). In the present investigation, spleen cells of mice immunized to sheep red cells (SRC) were similarly fractionated and the fractions recovered were assayed for: (a) reactivity to con A; (B) REACTIVITY TO SRC and (c) capacity to function as helper cells when stimulated with the homologous (SRC) or with a heterologous (donkey red cells) (DRC) antigen. Two subpopulations of cells reacting to con A were found in the spleens of the primed mice, corresponding to the subpopulations found in the non-immune mice. Both subpopulations contained cells responding to SRC (as measured by thymidine incorporation) and cells endowed with helper activity. The two subpopulations appeared to differ, however, in their specificity: while the denser cells could only exert their helper effect when stimulated by the specific antigen, the light cells could be effectively stimulated by both the specific (SRC) and the nonspecific (DRC) antigen.

Animals↗
PubMed1975

Subpopulations of mouse spleen lymphocytes. III. Cellular interactions in the response to concanavalin A.

The profile of response to concanavalin A (con A) of purified mouse T cells was found to differ appreciably from that of non-fractionated spleen cells, in agreement with results previously published by other investigators. Experiments designed to elucidate the reasons underlying these differences have revealed that the response of the spleen cells to con A is determined by a complex interplay between several cell types. (a) B cells contribute to the overall incorporation of thymidine in the presence of con A-stimulated T cells. However, the B cells participate in the response only if the T cells are dividing. (b) A population of 'adherent cells' is present in the spleen, which enhances the stimulation of the spleen cells by low doses of con A but suppresses the response to high doses of mitogen. These adherent cells include most likely the conventional macrophages, but probably also a population of 'suppressor T cells'. (c) Such 'suppressor T' cells can be readily detected among the peritoneal exudate cells. Addition of the exudate cells to cultures of purified T cells enhances the response to low doses of con A. This effect can be further increased by treating the peritoneal cells with a cell T-specific antiserum and complement, i.e. by eliminating the T cells.

Animals↗