G. De Panfilis et al., Identification of fas-L-expressing apoptotic T lymphocytes in normal humanperipheral blood - In vivo suicide, AM J PATH, 158(2), 2001, pp. 387-391
Citations number
48
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Medical Research Diagnosis & Treatment
Fas-L molecules expressed by in vitro stimulated T cells may be critically
involved in suicidal activation-induced cell death (AICD) of such cells thr
ough engagement of their Fas receptors, A similar suicide of T cells was po
stulated to occur even in vivo, to eliminate dangerous activated lymphocyte
s; however, the demonstration of suicidal AICD of T cells in healthy humans
in vivo is still lacking. We therefore investigated the possible occurrenc
e of Fas-L-linked suicidal apoptosis of T cells in normal human peripheral
blood. For this purpose, we took advantage of immunoelectron microscopy, wh
ich allows simultaneous visualization of the morphological apoptotic cellul
ar changes together with surface expression of Fas-L molecules. Very few T
lymphocytes were observed showing the ultrastructural features of apoptotic
lymphocytes; these occasional apoptotic T cells, together with the majorit
y of the normal T cell population, expressed the Fas molecule on the plasma
membrane, as expected. Interestingly, the apoptotic cells were also Fas-L-
positive, whereas normal T cells were Fas-L-negative. Such Fas-L-associated
T cell suicide operating in vivo in healthy individuals is presumably able
to suppress Immune responses and prevent autoreactivity, thus maintaining
the homeostasis of human-blood.