The inhibitory effect of human syncytiotrophoblast plasma membrane vesicles on in vitro lymphocyte proliferation is associated with reduced interleukin 2 receptor expression.
The mechanisms by which vesicles of syncytiotrophoblast plasma membranes (STPM) prepared from full-term human placentas inhibit lymphocyte proliferation have been investigated. In the presence of STPM, IL-2 secretion and the expression of protein P55 (IL-2R P55) from its receptor were examined in two models of PBMC proliferation: induced by PHA in 3-day-old cultures, and induced by IL-2 in 6-day-old cultures. In the case of PHA stimulation, STPM strongly inhibited IL-2 (but not IL-1) secretion and IL-2R P55 expression at a concentration where lymphocyte proliferation was also blocked. In these conditions, the addition of excess recombinant IL-2 (rIL-2) only partially restored proliferation and IL-2R P55 expression. In addition, STPM inhibited proliferation and IL-2R P55 expression when resting PBMC were stimulated by a high concentration of rIL-2. These results suggest that STPM inhibit lymphocyte proliferation by affecting one or several events occurring in the synthesis and/or expression of IL-2R P55 by a mechanism which is at least partially independent of its inhibitory effect on IL-2 secretion. The significance of these results is discussed in the context of the survival of the fetal allograft.
Laboratoire d'Immunologie, Faculté de Médecine, Tours, France.
G
G
Thibault
D
D
Degenne
A C
AC
Girard
J M
JM
Guillaumin
M
M
Lacord
P
P
Bardos
D002462:Cell Membrane / Q000502:physiology; D005260:Female; D015726:Giant Cells / Q000502:physiology*; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D010835:Phytohemagglutinins; D011247:Pregnancy; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D014327:Trophoblasts / Q000502:physiology*
D007375:Interleukin-1; D007376:Interleukin-2; D010835:Phytohemagglutinins; D015375:Receptors, Interleukin-2