Fas ligand is not only expressed in immune privileged human organs but is also coexpressed with Fas in various epithelial tissues.

Abstract

Ains-To confirm the recent data obtained in mice, showing that the Fas ligand (FasL) is involved in the phenomenon of "immune privilege"(the apparent defect ofthe immune system in specific anatomical sites) and to extend this finding to humans. Methods-The expression of FasL was analysed in a panel of histologically normal human tissues by reverse transcriptase polymerase chain reaction and Western blotting. The tissues sampled were brain, breast, bone marrow, oesophagus, kidney, liver, lung, lymph node, ovary, pancreas, pituitary gland, prostate, spleen, stomach (antrum and fundus), striated muscle, testis, thyroid, and uterus. These were obtained from patients with various neoplastic and nonneoplastic disorders; placental tissue was obtained after normal obstetric delivery, and spontaneous or voluntary abortion. Results-Strong FasL expression was detected in testis and placenta. FasL expression was also detectable, although it was seen to a lesser extent, in oesophagus, prostate, lung, and uterus, which also coexpressed variable amounts of Fas mRNA or protein or both. The other organs tested for FasL expression were all negative. Conclusions-FasL in humans is expressed predominantly in immune "sanctuaries" such as testis and placenta, suggesting that, similar to mice, this expression may contribute to the immune privileged status of these organs, by preventing dangerous inflammatory responses. The coexpression ofFasL and Fas in particular epithelia suggests that the physiological cell turnover of some tissues may be regulated by the Fas-FasL apoptotic pathway.

Involvement of Soluble CD95 in Churg-Strauss Syndrome

“…Because normal gastric epithelia are known to express CD95 but not CD95L, 23 extensive CD95L expression in the area of affected gastric mucosa could account for the ulcerative tissue damage observed in this case. The contribution of IEL to CD95L expression in ulcerative gastric mucosa was estimated by quantitative RT-PCR using CD3␦ chain-specific primers.…”

Synthetic retinoids as inducers of apoptosis in ovarian carcinoma cell lines

“…These tissues are called immune privileged tissues (Watanabe-Fukunaga et al, 1992;Leithauser et al, 1993;Hiramatsu et al, 1994;Galle et al, 1995;Xerri et al, 1997;Guller and LaChapelle, 1999;Bernstorff et al, 2002;Niederkorn, 2002). Immune privilege occurs because these tissues express CD95 ligand normally on their surface and normal monitoring immune cells carry the death receptors resulting in a clearing of the immune cells via apoptosis (Krammer, 1998).…”

Circulating miR-21, miR-146a and Fas ligand respond to postmenopausal estrogen-based hormone replacement therapy – A study with monozygotic twin pairs

“…It belongs to the TNF family and its main function is the induction of apoptosis in susceptible and Fas receptor expressing cells (Takahashi, et al 1994). There are two types of FasL: the pro-apoptotic membrane bound form, which is primarily expressed in activated T lymphocytes and immuneprivileged organs (Xerri, et al 1997) -and the soluble one (sFasL), which originates from the membrane-bound FasL by matrix metalloproteinase-mediated cleavage. The physiological role of sFasL is controversial since it has been reported to induce non-apoptotic signals, possibly including NF-kβ-mediated stimulation of cell proliferation, survival or inflammation within an elevated cytokine milieu (Suda, et al 1997, Mogi, et al 2001, Serrao, et al 2001).…”