Alteration of CD44 expression in HIV type 1-infected T cell lines.

CD44 is known to interfere in HIV replication and to participate in many physiological processes such as lymphocyte binding to high endothelial venules of lymphoid tissue, lymph nodes, and mucosal endothelium. The T cell lines MOLT-4 and CEM, and CEM subclones were infected with the HIV-1 LAI strain and monitored for the expression of CD44 during the course of chronic virus production until the infected cells were at the stage of latent infection. The levels of CD44 protein expression were quantified using cell surface immunostaining and biotinylation.

Autoantibodies directed against CD43 molecules with an altered glycosylation status on human immunodeficiency virus type 1 (HIV-1)-infected CEM cells are found in all HIV-1+ individuals.

Autoantibodies to lymphocytes have been detected in sera from human immunodeficiency virus type 1 (HIV-1)-infected individuals, and several autoantigens have been described. Among them, hyposialylated CD43 has been shown to be a target for autoantibodies in up to 47% of HIV+ individuals. However, the corresponding autoantigen (ie, the incompletely sialylated CD43) has not been isolated from blood cells of HIV-1-infected individuals.

Lymphocytic CD43 and CD45 bear sulfate residues potentially implicated in cell to cell interactions.

CD43 is a major heavily glycosylated lymphocyte surface molecule. It has been shown to play an important role in lymphocyte activation and cell-cell interactions. Here we demonstrate that in human activated lymphocytes and CEM T cells, CD43 is a sulfated molecule.

Altered glycosylation of leukosialin, CD43, in HIV-1-infected cells of the CEM line.

CD43 (leukosialin, gpL115, sialophorin) is a major sialoglycoprotein widely expressed on hematopoietic cells that is defective in the congenital immunodeficiency Wiskott-Aldrich syndrome. It is thought to play an important role in cell-cell interactions and to be a costimulatory molecule for T lymphocyte activation. Using a metabolic 35SO4(2-) radiolabeling assay or biotinylation of cell surface proteins, we describe here that CD43 are sulfated molecules the glycosylation of which is altered in human immunodeficiency virus type 1 (HIV-1)-infected leukemic T cells of the CEM line.

CD3-stimulated Jurkat T cells mediate IL-1 beta production in monocytic THP-1 cells. Role of LFA-1 molecule and participation of CD69 T cell antigen.

In this study we investigated the T cell signals required for monocyte activation. We used an in vitro co-culture system involving two human cell lines: Jurkat T cells and THP-1 monocytes. Monocyte activation was monitored by measuring IL-1 beta production, whereas IL-2 secretion reflected Jurkat activation.

Inhibition of phorbol ester-induced cell activation in microgravity.

T lymphocytes and monocytes were exposed to microgravity and activated to produce interleukin 2 and interleukin 1, respectively. When Jurkat T cells were triggered with monoclonal antibodies directed against the CD3/T cell receptor complex in the presence of THP-1 monocytes used as accessory cells, cell-to-cell contacts took place in microgravity leading to normal production of interleukin 2 and interleukin 1, as compared to ground controls. In contrast, when cells were individually stimulated by soluble substances including a protein kinase C activating phorbol ester, the production of interleukin 1 and interleukin 2 was dramatically inhibited during microgravity exposure.

Isolation and characterization of a T lymphocyte mutant defective in the protein kinase C signal transduction pathway.

The phorbol ester TPA is a potent protein kinase C (PKC) activator and a cofactor in the activation of the human Jurkat leukemic T cell line. We have studied the implication of the PKC signaling pathway in the process of T cell activation by generating TPA resistant mutants of Jurkat. These mutants were obtained by recovery of cells that survived a growth arrest induced by TPA.

Stimulation of human interleukin 1 production and specific mRNA expression by microtubule-disrupting drugs.

The production of interleukin 1 (IL1), a pleiotropic monocyte-derived interleukin, can be induced in vitro by various stimuli. The present study shows that cytochalasins which inhibit actin filament polymerization in various cell types have no significant effect on IL1 production from human monocytic cells. On the contrary, microtubule disrupters such as colchicine, vinblastine, and vincristine dramatically potentiate (15- to 35-fold), in a dose-dependent fashion, cell-associated IL1 and to a lesser extent (2.