Effect of cyclosporin A on the function of T cells

Cyclosporin A inhibits the delayed-type hypersensitivity effector function of T lymphocytes without affecting their clonal expansion

The effect of an immunosuppressor, cyclosporin A (CsA), on the induction by sheep erythrocytes of T cells mediating the delayed-type hypersensitivity (DTH) reaction was investigated using a quantitative assay of DTH-mediating T lymphocytes. CsA administration did not affect their clonal expansion following immunization. The frequency of the DTH-mediating T cells was not significantly different in mice sensitized by antigens in the presence or absence of CsA. However, CsA interfered with expression of effector function of DTH-mediating T lymphocytes by impairing the production of pro-inflammatory factor(s). Resting T cells as well as blast T cells were sensitive to this inhibitory effect of CsA.

Cyclosporin A inhibits the delayed-type hypersensitivity reaction: impaired production of early pro-inflammatory mediator(s)

The effect of cyclosporin A (CsA) on the delayed-type hypersensitivity (DTH) elicited in mice by sheep red blood cells was investigated. Evidence is presented that a single injection of CsA adversely affects the inflammatory reaction. Sensitized T lymphocytes initiate the DTH reaction by their recruiting activity on phagocytic cells which infiltrate the cutaneous site of antigen deposition. CsA administration has no adverse effect on the recruitment of phagocytic cells at the site of the inflammatory reaction. The present studies show that CsA acts on specific T cells: (a) in adoptive transfer, T-DTH-mediating cells cannot elicit a response in mice treated with CsA 8 h before; (b) when collected 8 h after a single injection of CsA, T-DTH-mediating lymphocytes are no longer able to adoptively transfer the reaction. This conclusion is strengthened by in vitro studies: (a) the frequency of T-DTH-mediating lymphocytes is 50-fold decreased after a short in vitro incubation with CsA; (b) in vitro production by concanavalin A-activated lymphocytes of chemotactic pro-inflammatory mediator(s) is abolished in presence of CsA.

Immunoenhancing effect of flavonoid compounds on lymphocyte proliferation and immunoglobulin synthesis

Flavonoid compounds are lipophilic agents which can interact with membrane lipids and may affect responsiveness of immune cells. We therefore studied whether cianidanol ((+)-catechin), the O-methyl-derivative (+)-3-methoxy-5,7,3',4'-tetrahydroxyflavan and palmitoyl-derivative (+)-3-palmitoyl-5,7,3',4'-tetrahydroxyflavan influence T and B cell functions. In addition, immunomodulatory property of ubiquinone 50 was also investigated. As controls were used cyclosporin A and inosine which are known to inhibit or enhance immune responses, respectively. The in vitro spontaneous, antigen and mitogen induced proliferation as well as immunoglobulin synthesis of peripheral blood mononuclear cells from healthy individuals was determined in the presence of different concentrations of the agents. All flavonoid compounds and ubiquinone 50 significantly increased (p less than 0.05 - less than 0.01) the spontaneous lymphocyte transformation but hardly affected antigen, alloantigen and mitogen induced proliferative response. Only cianidanol and O-methyl-derivative enhanced significantly (p less than 0.05 - less than 0.01) spontaneous, pokeweedmitogen and Staphylococcus aureus Cowan I induced immunoglobulin synthesis while the palmitoyl-derivative and ubiquinone 50 had only minor influence on B cell function. In contrast, Staphylococcus aureus induced immunoglobulin production was neither increased by inosine nor suppressed by cyclosporin A. These studies show that especially cianidanol and the O-methyl-derivative can exert an immunoenhancing effect on T and B cell functions.

Functional evaluation of murine allogeneic T lymphoblasts separated by Vicia villosa lectin positivity

Mixed-lymphocyte culture-stimulated cells have been fractionated by their ability to bind the lectin Vicia villosa (Vv) and assessed for their cytolytic and suppressor activity in vitro. Vv positive and negative cells were separated either by cell affinity chromatography using Vv-Sepharose 6MB chromatography or by electronic cell sorting with FITC-Vv. Both populations expressed marked cytolytic and suppressor cell activity. Thus this lectin cannot be used to discriminate between these and other functional lymphoid cell population of blastoid cells binding the FITC-Vv appears following allogeneic stimulation; treatment with the immunosuppressive drug cyclosporin A, which affects cytotoxic cells preferentially, results in a considerable reduction of the Vv positive blastoid cells.