Colony formation by subpopulations of T lymphocytes. IV. Inhibitory effect of hydrocortisone on human and murine T cell subsets.

The sensitivity of human T lymphocyte colony formation to hydrocortisone (HCS) was studied in the presence and absence of an exogenous source of interleukin-2(IL-2). In the presence of IL-2, T colony formation by T inducer/helper (Th) cells was found to be 100-fold more resistant to the inhibitory effect of HCS in vitro than colony formation by T suppressor/cytotoxic (Tsc) cells, the IC50 values for HCS being 10(-4)M and 10(-6)M, respectively. In the absence of IL-2,Tsc cells do not form colonies and T cell colony formation by Th cells is inhibited 50% by less than 5 x 10(-8)M HCS. T lymphocyte colony formation by murine cortical thymocytes in vitro was inhibited by physiological concentrations of HCS in vitro, the IC50 value being 2 x 10(-8)M HCS. T cell colony formation by medullary thymocytes and peripheral lymphocytes was found to be 100-fold more resistant to HCS than control cells, the IC50 value being 2 x 10(-6)M HCS

Identification of differentially expressed proteins in spontaneous thymic lymphomas from knockout mice with deletion of p53

BACKGROUND: Knockout mice with a deletion of p53 spontaneously develop thymic lymphomas. Two cell lines (SM5 and SM7), established from two independent tumours, exhibited about fifty to seventy two-fold differentially expressed proteins compared to wild type thymocytes by two-dimensional gel electrophoresis (2D-PAGE). RESULTS: Protein spots excised from 2D-PAGE gels, were subjected to in-gel tryptic digestion and identified by liquid chromatography – tandem mass spectrometry. A total of 47 protein spots were identified. Immunological verification was performed for several of the differentially regulated proteins where suitable antibodies could be obtained. Functional annotation clustering revealed similarities as well as differences between the tumours. Twelve proteins that changed similarly in both tumours included up-regulation of rho GDP-dissociation inhibitor 2, proteasome subunit α type 3, transforming acidic coiled-coil containing protein 3, mitochondrial ornithine aminotransferase and epidermal fatty acid binding protein and down-regulation of adenylosuccinate synthetase, tubulin β-3 chain, a 25 kDa actin fragment, proteasome subunit β type 9, cofilin-1 and glia maturation factor γ. CONCLUSION: Some of the commonly differentially expressed proteins are also differentially expressed in other tumours and may be putative diagnostic and/or prognostic markers for lymphomas

Specific antibody-forming B-lymphocyte colonies. I. Distribution and nature of SRBC antibody-forming B-lymphocyte colonies in mouse lyphomyeloid organs.

Wehn normal mouse spleen or lymph node cells are cultured for 7 days in agar-medium containing 2-mercaptoethanol and sheep red blood cells (SRBC), approximately one B lymphocyte colony (BLC) develops per 50-100 cells seeded. Incubation of cultures for 3 h with guinea-pig complement at day 7, demonstrated that 0.05-0.25% of all BLC form specific antibody against SRBC (SRBC-AF-BLC). The SRBC specific colonies appear centrally in lytic plaques of 2-5 mm in diameter and cells recovered from individual SRBC-AF-BLC were shown to produce antibodies of the IgM class against SRBC. Cells forming SRBC-AF-BLC are absent in the new-born and infantile spleen but appear in adult mice with a frequency of 5, 10-25 and 25-70 per 10(6) bone marrow, spleen and lymph node cells respectively. specific immunization in vivo or in vitro does not greatly affect the number of SRBC-AF-BLC-forming cells. Cytolysis of spleen cells with anti-Ig serum plus complement prior to culture reduced the number of total BLC and that of specific SRBC-AF-BLC by 93% and 94% respectively. The peak sedimentation velocity of both SRBC-AF-BLC-forming cells and total BLC-forming cells was 3.5 mm/h. Spleen cells enriched 200-300 times for cells that bind specifically to the hapten NIP were not enriched for cells forming colonies with specific antibody production against NIP. The data indicate that the cells that give rise to specific antibody-forming colonies belong to a mature virgin B cell group of small Ig-positive B lymphocytes