Search results for "Lymphokines"
showing 10 items of 29 documents
T-cell-derived helper factor allows in vivo induction of cytotoxic T cells in nu/nu mice
1980
T-cell immunocompetence and diversity are thought to be generated in the thymus1,2. This view is based on the findings that (1) T-cell ontogeny is thymus dependent3,4, (2) the major histocompatibility restrictions of T-cell interactions are phenotypically related to the H–2 type of the thymus5–9, and (3) the phenotypic manifestation of H–2-linked immune responsiveness parallels the restriction elements selected in thymus10–12. However, it is unclear whether pre-thymic cells programmed to develop into T cells do already express a receptor diversity, also whether pre-thymic cells have the potential to react against self-antigens, and whether the mechanism of self-tolerance is initiated in the…
The in Vivo Effects of Interleukin 2 (TCGF)
1982
This brief review of our experiments concerning the in vivo activity of crude Il-2 led us to the following conclusion: The first is the existence, in vivo, of a cyclophosphamide-sensitive T-cell controlling the activity of a serum born Il-2 inhibitor in thymus-bearing normal mice. Under in vivo conditions which are characterized by high Il-2 inhibitor activities, locally applied Il-2 administered along with antigen amplified in vivo CTL-responsiveness, yet the effect observed was poor. Crude Il-2 proved to be a potent immuno-enhancing agent in the athymic (nu/nu) mouse, which lacks Il-2 inhibitor activity. It was found that together with antigen administration of Il-2 to nude mice results i…
Phosphodiesterase inhibitor pentoxifylline, a selective suppressor of T helper type 1- but not type 2-associated lymphokine production, prevents indu…
1993
The phosphodiesterase inhibitor pentoxifylline (POX), which is known to have pharmacological effects in animal models of multiorgan failure and endotoxin-mediated shock, was tested for its immunosuppressive potential on T lymphocyte activation in vitro and in vivo. POX was found to have a profound inhibitory effect on both mitogen- and antigen-induced proliferation of CD4+ T cells in vitro. This inhibitory activity of the drug could be reproduced by treating T lymphocytes with cAMP analogues during stimulation. Responses of repeatedly in vitro stimulated cells were much more strongly inhibited by the drug and by cAMP analogues than responses of fresh resting lymphocytes. Furthermore, POX co…
Sumoylation of the transcription factor NFATc1 leads to its subnuclear relocalization and interleukin-2 repression by histone deacetylase.
2009
The family of NFAT (nuclear factor of activated T-cells) transcription factors plays an important role in cytokine gene regulation. In peripheral T-cells NFATc1 and -c2 are predominantly expressed. Because of different promoter and poly(A) site usage as well as alternative splicing events, NFATc1 is synthesized in multiple isoforms. The highly inducible NFATc1/A contains a relatively short C terminus, whereas the longer, constitutively expressed isoform NFATc1/C spans an extra C-terminal peptide of 246 amino acids. Interestingly, this NFATc1/C-specific terminus can be highly sumoylated. Upon sumoylation, NFATc1/C, but not the unsumoylated NFATc1/A, translocates to promyelocytic leukemia nuc…
Lymphokine profile and activation pattern of two unrelated antigen- or idiotype-specific T suppressor cell clones.
1992
Two T suppressor (Ts) clones of different specificity have been analyzed for their lymphokine spectrum. BVI/5 is an I-Ek-restricted bovine serum albumin (BSA)-specific Ts cell clone from a CBA/J mouse tolerized by low doses of BSA. It affects directly or indirectly the function of BSA-specific T helper (Th) cells. The Ts cell clone 178-4 from a BALB/c mouse is I-Ed restricted and recognizes the public J558 Id on B cells. It prevents alpha(1----3)dextran B 1355S (Dex)-specific IgG antibody production and drives Dex-specific J558 idiotype-bearing B cells into an anergic B IgG memory cell state. Both Ts cell clones thus cause specific suppression, yet in different experimental systems using di…
B8, DR3 antigens and production of human leucocyte migration inhibitory factor (LIF) by mononuclear cells stimulated with concanavalin A (Con A)
2008
LIF release by Con A stimulated mononuclear cells was evaluated in 67 randomly selected healthy Sicilians typed for HLA antigens. The results show that B8 and/or DR3 positive subjects release less LIF than negative ones, suggesting that this immunological response might be controlled by HLA-linked immune response (Ir) gene(s).
Spontaneous lymphokine production by human B lymphocytes.
2009
When human blood lymphocytes are cultured in vitro without any intended stimulus, they produce activities in the supernatant resembling lymphokine. This phenomenon was further investigated in the present study, where it has been demonstrated by physicochemical characterization and inhibition experiments that leukocyte migration inhibitory activity in the supernatants is due to leukocyte inhibitory factor (LIF). When T and B lymphocytes were purified by carbonyl iron and SRBC-rosette sedimentation, only B cells produced LIF and leukocyte chemotactic lymphokine(s) in subsequent cultures. B cells elaborated lymphokines without the help of T cells, the need for co-operation of monocytes was als…
Biochemical properties of MHC class II molecules endogenously synthesized and expressed by mouse Langerhans cells
1991
The cell surface expression and biosynthesis of Langerhans cells (LC)-derived major histocompatibility complex (MHC) class II molecules from epidermal cells (EC) prepared freshly and cultured for up to 3 days was investigated. Based on the constitutive expression of MHC class II determinants by LC, a panning and magnetic bead selection procedure was employed, yielding 65% and 86% of I-A+ cells, respectively. Phenotypical and cytochemical examinations revealed that the two LC preparations were free of contaminating macrophages as well as B and T cells. Freshly prepared enriched LC were highly efficient in the stimulation of protein antigen-specific T cell clones, while LC purified from short…
Characterization of a T-cell-derived mast cell costimulatory activity (MCA) that acts synergistically with interleukin 3 and interleukin 4 on the gro…
1990
The proliferation of mucosal mast cells (MMC) depends on the presence of interleukin 3 (IL 3) and can be further enhanced by interleukin 4 (IL 4). The supernatant of a TH2 cell clone (ST2/K.9) stimulated by concanavalin A was found to contain a factor, provisionally termed mast cell costimulatory activity (MCA), that substantially enhances the proliferation of MMC promoted by a combination of IL 3 and IL 4. In comparison to other lymphokines MCA is rather resistant to tryptic digestion but is very sensitive to pH values lower than 6.0 and to organic solvents. Chromatographic fractionation of MCA revealed that activity is associated with protein(s) or glycoprotein(s) of 35 to 40 kDa. Partial…
The role of accessory cells in polyclonal T cell activation. I. Both induction of interleukin 2 production and of interleukin 2 responsiveness by con…
1983
Recent studies from other laboratories have shown that concanavalin A (Con A) acts at two separate steps in polyclonal T cell activation: interleukin 2 (IL2) production, and induction of responsiveness to IL2. Using a combination of techniques for the depletion of accessory cells from lymph node T cells, we have investigated which of these steps, if not both, is responsible for the known requirement for accessory cells in the Con A response. It was found that with increasing T cell purification, first the ability is lost to produce sufficient levels of endogenous IL2, whereas induction of IL2 responsiveness can still take place. Further removal of accessory cells however yields a population…