Polyclonal human T-cell activation by silicate in vitro.
Silica (SiO2) or related substances such as silicone ([-R2Si-O-]n), which is used in plastic surgery, or asbestos (e.g. chrysotile; 3MgO.2SiO2.H2O) have 'adjuvant effects'. In a study of scleroderma patients in Germany more than 78% had experienced exposure to silicate dust. T-cell receptor (TcR) V beta gene analysis on CD4- CD8- double-negative alpha beta T cells from scleroderma patients, using polymerase chain reaction (PCR), showed that certain V beta genes, V beta 5, V beta 7 and V beta 17, were predominantly expressed in the cells. We found that certain V beta repertoires, V beta 5.3 and V beta 6.7, were predominantly expressed on fractionated T cells with a high Ca2+ level that had been stimulated by chrysotile in vitro. The intracellular Ca2+ level in human peripheral blood mononuclear cells (PBMC) increased after incubation with silica or chrysotile. Interleukin-2 (IL-2) release from PMBC also rose significantly with chrysotile stimulation, but no change was observed when major histocompatibility complex (MHC) class II DP/DR positive cells were depleted. Therefore, our results support the possibility that silicate acts as a superantigen.
Ueki
A
A
Department of Hygiene, Kawasaki Medical School, Kurashiki, Japan.
Yamaguchi
M
M
Ueki
H
H
Watanabe
Y
Y
Ohsawa
G
G
Kinugawa
K
K
Kawakami
Y
Y
Hyodoh
F
F
D000328:Adult; D017632:Asbestos, Serpentine / Q000276:immunology*; D002118:Calcium / Q000097:blood; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000097:blood; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis / Q000235:genetics; D012822:Silicon Dioxide / Q000276:immunology*; D018089:Superantigens / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D017632:Asbestos, Serpentine; D007376:Interleukin-2; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens; D012822:Silicon Dioxide; D002118:Calcium