PubMed Health⌕ Search

Biomedical subjects

A Novogrodsky

Publications and source records attributed to A Novogrodsky.

At least 145 records · Page 8Linked to original sources
PubMed1973

Induction of lymphocyte transformation by sequential treatment with neuraminidase and galactose oxidase.

Treatment of mouse-spleen cells with galactose oxidase (EC 1.1.3.9) after incubation with neuraminidase (EC 3.2.1.18) induced extensive blastogenesis. Treatment of the cells with galactose oxidase before incubation with neuraminidase had very little stimulatory effect. Either of these enzymes alone had practically no effect on the cells. The lymphocyte transformation induced by galactose oxidase in neuraminidase-treated cells was decreased upon reacting the cells with borohydride or hydroxylamine, whereas treatment with these compounds did not affect transformation of cells by concanavalin A. It is suggested that galactosyl residues exposed by the action of neuraminidase on the cell membrane are oxidized by galactose oxidase, and the aldehyde moiety thus formed is involved in the induction of blastogenesis.

Alcohol Oxidoreductases↗
PubMed1973

Transformation of neuraminidase-treated lymphocytes by soybean agglutinin.

Transformation of mouse-spleen lymphocytes in the presence of soybean agglutinin is markedly enhanced after their treatment with neuraminidase (EC 3.2.1.18). Incubation of the cells with the enzyme also facilitates their agglutination by the lectin. The soybean agglutinin-induced agglutination and transformation is inhibited specifically by N-acetyl-D-galactosamine. New specific binding sites for soybean agglutinin were shown to appear after neuraminidase treatment. It is postulated that the transformation of neuraminidase-treated mouse-spleen lymphocytes induced by soybean agglutinin is caused by the binding of the lectin to galactosyl residues exposed by the action of neuraminidase on the cell membrane.

Animals↗
PubMed1972

Membrane site modified on induction of the transformation of lymphocytes by periodate.

Lymphocytes isolated from different sources undergo blastogenesis after mild treatment with periodate. Incubation of mouse spleen lymphocytes with neuraminidase or papain markedly reduces their response to periodate. Transformation induced by concanavalin A of the enzymically treated cells is not impaired. Blastogenesis induced by periodate is decreased when periodate-treated lymphocytes are reacted with borohydride, hydroxylamine, or semicarbazide. Treatment with these compounds does not affect transformation of cells by concanavalin A. It is suggested that different membrane sites are involved in lymphocyte transformation induced by periodate and by concanavalin A. The periodate target site seems to include a glycoprotein complex containing sialic acid that yields, on oxidation, an aldehyde moiety that is essential for transformation.

Animals↗
PubMedDate not supplied

1,25-Dihydroxyvitamin D3 acts directly on human lymphocytes and interferes with the cellular response to interleukin-2.

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) inhibits mitogen-induced lymphocyte proliferation in peripheral blood mononuclear cell preparations. Receptors for 1,25(OH)2D3 are present in monocytes and are acquired by lymphocytes upon activation. It is not clear whether the hormone inhibits lymphocyte mitogenesis by a direct action on the lymphocyte or only indirectly by affecting the regulatory monocytes. We addressed this question by using highly purified human lymphocyte preparations which contain less than 0.1% monocytes. 1,25(OH)2D3 inhibited the stimulation of purified lymphocytes by phytohemagglutinin and in the presence of fixed accessory cells, which cannot respond to 1,25(OH)2D3. The inhibitory effect attained 35% similar to that obtained in the presence of monocytes. 1,25(OH)2D3 inhibited interleukin 2 (IL-2)-driven stimulation of purified T cells in three different systems: cells treated with a submitogenic concentration of phytohemagglutinin, IL-2-dependent cells which bear receptors for IL-2 and naive cells in the absence of other mitogens. We conclude: (1) the human T lymphocyte is a direct target for 1,25(OH)2D3; (2) 1,25(OH)2D3 inhibits the response of activated, IL-2-receptor-bearing human T cells to interleukin-2.

Calcitriol↗