Cell culture

About: Cell culture is a research topic. Over the lifetime, 133361 publications have been published within this topic receiving 5364150 citations. The topic is also known as: cell culture techniques.

Ability of HIV to promote a TH1 to TH0 shift and to replicate preferentially in TH2 and TH0 cells

Abstract: Both interferon gamma (IFN-gamma) produced by T helper 1 (TH1) lymphocytes and interleukin-4 (IL-4) produced by TH2 lymphocytes were reduced in either bulk circulating mononuclear cells or mitogen-induced CD4+ T cell clones from the peripheral blood of individuals infected with human immunodeficiency virus (HIV). There was a preferential reduction in clones producing IL-4 and IL-5 in the advanced phases of infection. However, enhanced proportions of CD4+ T cell clones producing both TH1-type and TH2-type cytokines (TH0 clones) were generated from either skin-infiltrating T cells that had been activated in vivo or peripheral blood T cells stimulated by antigen in vitro when cells were isolated from HIV-infected individuals. All TH2 and most TH0 clones supported viral replication, although viral replication was not detected in any of the TH1 clones infected in vitro with HIV. These results suggest that HIV (i) does not induce a definite TH1 to TH2 switch, but can favor a shift to the TH0 phenotype in response to recall antigens, and (ii) preferentially replicates in CD4+ T cells producing TH2-type cytokines (TH2 and TH0).

Cyclic x ray responses in mammalian cells in vitro.

Abstract: Various radiation responses in mammalian cells depend on the position of the cell within its generation cycle (that is, its age) at the time of irradiation. Studies have most often been made by irradiating synchronized populations of cells in vitro. Results in different cell lines are not easy to compare, but an attempt has been made here to point out similarities and differences with regard to cell killing and division delay. In general, survival data obtained so far show that, in cells with a short G1, cells are most sensitive in mitosis and in G2, less sensitive in G1, and least sensitive during the latter part of the S period. In cells with a long G1, in addition to the above, there is usually a resistant phase early in G1 followed by a sensitive stage near its end. (The latter may be as sensitive as mitosis.) Exceptions to the above, especially in some L cell sublines, have been noted, and a possible explanation is given. In Chinese hamster cells, maximum survival after irradiation occurs during S, b...

Proteolytic Enzymes Initiating Cell Division and Escape from Contact Inhibition of Growth

Abstract: BRIEF treatment with very low concentrations of proteolytic enzymes can bring about a change in the cell surface similar to that occurring in the chemical or viral transformation of normal to malignant cells1. This suggests to us that proteolytic enzymes may not only convert the surface structure into the type seen in malignant cells but that the whole cell may respond to the proteolytic enzyme with initiation of new rounds of cell division and a concomitant escape from contact inhibition of growth, as is the case for malignant cells in tissue culture2.

Interaction of the carbohydrate-binding protein concanavalin a with normal and transformed cells

Abstract: It has been shown that the carbohydrate-binding protein concanavalin A (ConA) can agglutinate leukemic cells and cells transformed by polyoma virus, simian virus 40, chemical carcinogens, and X-irradiation. This protein did not agglutinate normal cells under the same conditions. The agglutination was reversed by competition with α-methyl-D-glucopyranoside (α-MG), a carbohydrate that strongly binds to ConA, but not by the carbohydrates α-methyl-L-fucopyranoside or N-acetylglucosamine, with no binding or weak binding to ConA. Destruction of the α-MG binding sites of the native protein by removal of bivalent metal ions abolished the agglutination produced by the native protein. The treatment of cells with trypsin resulted in the agglutination of normal cells by ConA and a decrease of agglutinability of transformed cells. When nonagglutinating untransformed 3T3 cells were infected with simian virus 40 and normal rat cells were infected with polyoma virus, the infected cells became agglutinable several days after virus infection. The percentage of cells agglutinated, about 50 per cent, was much higher than the percentage of cells hereditarily transformed. The results indicate that the surface membrane of transformed cells contains sites that interact with the α-MG binding sites of ConA, that such sites can be found on the surface membrane of normal cells after treatment with trypsin, and that the change in the surface structure from normal to transformed occurs in cells that are abortively transformed.

The bone marrow-derived stromal cell lines MC3T3-G2/PA6 and ST2 support osteoclast-like cell differentiation in cocultures with mouse spleen cells.

Abstract: After our previous report that osteoclast-like multinucleated cells (MNCs) were formed in response to lα,25- dihydroxyvitamin D3 [lα,25-(OH)2D3] in cocultures of mouse spleen cells and osteoblast-rich populations freshly isolated from fetal mouse calvariae, we examined whether such primary osteoblast- like cells can be replaced by established cell lines in inducing osteoclast-like cell formation. We first used two clonal cell lines simultaneously established from newborn mouse calvariae. One was the osteoblastic cell line MC3T3-E1, and the other was the preadipose cell line MC3T3-G2/PA6. Tartrateresistant acid phosphatase (TRACP; a marker enzyme of osteoclasts)-positive mononuclear cells and MNCs were formed in the cocultures of spleen cells and MC3T3-G2/PA6 cells in the presence of lα,25-(OH)2D3. Dexamethasone greatly potentiated TRACP-positive MNC formation induced by lα,25-(OH)2D3, whereas the glucocorticoid alone had no effect on it. In contrast, osteoblastic MC3T3-E1 cells failed to induce T...