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- Loftenius, A, et al.
(författare)
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Fluoride augments the mitogenic and antigenic response of human blood lymphocytes in vitro
- 1999
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Ingår i: Caries research. - : S. Karger AG. - 0008-6568 .- 1421-976X. ; 33:2, s. 148-155
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Tidskriftsartikel (refereegranskat)abstract
- It has been shown that fluoride, the agent responsible for reduction of dental caries worldwide and a recognized proliferative agent, is an adjuvant when given intragastrically to rats. Furthermore, plasma fluoride levels increase in humans after various fluoride treatments. The studies presented here show that fluoride also has the ability to affect the cells of the human immune system. This was tested by measuring the effect of sodium fluoride (NaF) on cytokine production by human whole blood cells stimulated in vitro. These studies revealed that NaF augments the human lymphocyte response from human blood to a mitogen (phytohemagglutinin, PHA) or a specific antigen (morbilli antigen from infected cells, MorbAg). The cytokine interferon–γ (IFN–γ), released from activated T and/or NK cells, was significantly (p<0.01) increased when whole blood cells were simultaneously incubated with 0.62 mmol/l NaF and PHA compared to PHA alone. This tendency was also true for NaF and MorbAg. The lymphocyte activation marker interleukin–2 receptor (measured in soluble form) increased after simultaneous stimulation of the cells with PHA and 0.62 mmol/l NaF compared to stimulation with PHA only. However, 0.62 mmol/l NaF did not enhance interleukin–6 release, in blood mainly produced by monocytes. The ability to influence the IFN–γ release during an immune response could be one of the primary means by which the fluoride ion influences the immune system.
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- Loftenius, A, et al.
(författare)
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HgCl(2)-induced human lymphocyte activation in vitro: a superantigenic mechanism?
- 1999
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Ingår i: International archives of allergy and immunology. - : S. Karger AG. - 1018-2438 .- 1423-0097. ; 120:1, s. 63-70
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Tidskriftsartikel (refereegranskat)abstract
- Mercuric chloride (HgCl<sub>2</sub>) has been proposed to be a mitogen for human blood lymphocytes in vitro. In our previous study, we demonstrated that HgCl<sub>2</sub> preferentially stimulates the CD4+ T cell subset to blast transformation and DNA synthesis and that the reaction is dependent on CD14+ accessory cells. In order to characterise the responding cells further and to elucidate the mechanism of T cell activation, the T cell receptor (TCR) Vβ chain expression of the blast–transformed cells was analysed by monoclonal antibodies and flow cytometry. The 22 TCR–Vβ–specific antibodies used were found to react with 55–80% of the naive CD4+ and CD8+ blood T cells from the different donors. Six to 18% of the lymphocytes, mainly CD4+ T cells, were blast transformed after addition of HgCl<sub>2</sub>. The distribution of the lymphoblasts carrying certain TCR Vβ chains were skewed, and 15–40% expressed the TCR Vβ2 chain. Furthermore, if cells were pretreated for 5 days with HgCl<sub>2</sub>, whereafter recombinant interleukin–2 in fresh medium was added, the TCR Vβ7+ T cell subset was also stimulated to blast transformation. The superantigen staphyloccal enterotoxin B, as a control, induced blast transformation in 10–26% of the lymphocytes, mainly CD4+ T cells, which were, as expected, positive for Vβ3, Vβ12, Vβ14 or Vβ17. We conclude that HgCl<sub>2</sub> has characteristics of a superantigen, activating the human lymphocytes in a Vβ–chain–selective manner in vitro.
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- Loftenius, A, et al.
(författare)
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In vitro effects of mercuric chloride (HgCl2) on human mononuclear cells
- 1997
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Ingår i: Clinical and experimental immunology. - : Oxford University Press (OUP). - 0009-9104 .- 1365-2249. ; 110:3, s. 418-422
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Tidskriftsartikel (refereegranskat)abstract
- Due to the release of the toxic compounds of mercury from amalgam fillings, dental amalgam has been questioned as an adequate restoration material for tooth fillings. HgCl2 has been found to be mitogenic for human blood lymphocytes in vitro. However, activation required much higher concentrations than are ever found in vivo. This study has been initiated to evaluate further the influence of HgCl2 on human immunocompetent cells in vitro. It is found that HgCl2 in a narrow concentration range has the ability to preferentially stimulate the CD4+ T cell subset to blast transformation and DNA synthesis. The reaction, when monitored during days 2–6, is maximal at day 6, and most blasts express the IL-2 receptor (IL-2R), indicating in vitro activation. The CD8+ T cell subset is not affected to the same extent. In addition, HgCl2-induced lymphocyte reactivity is dependent on accessory cells, i.e. CD14+ cells.
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