A Placenta-Derived Suppressor Factor with a T-Cell Bias


Department of Microbiology, Faculty of Medicine, Kuwait University, PO Box 24923, Safat 13110 Kuwait. E-mail: raj@hsc.kuniv.edu.kw


Raghupathy R, Khan SFB, Syamasundar PV, Bansal P, Azizieh F. A placenta-derived suppressor factor with a T-cell bias. AJRI 1999; 42:205–218 © Munksgaard, Copenhagen

PROBLEM: Functional and mechanistic aspects of immunosuppression by murine placental supernatants (MPS) were investigated.

METHOD OF STUDY: MPS and a low molecular weight fraction of the supernatant (MPSf) were tested for suppressive action on T-cell reactivity in vitro and in vivo, on B-cell responses and on T-cell activation events.

RESULTS: MPS and MPSf suppress mitogen-induced proliferation and mixed lymphocyte reactions of human and murine lymphocytes, antigen-induced proliferation of T cells in vitro and in vivo, proliferation of CD8+ lymphocytes, proliferation induced by cross-linking of surface CD3 and the in vivo response of mice to allogeneic stimuli. MPSf affects cell cycling of activated T cells and blocks interleukin (IL)-2 production. MPSf does not affect antibody production or the induction of MHC class II expression on B cells.

CONCLUSIONS: MPSf is a potent inhibitor of T-cell responses in vitro and in vivo, with no demonstrable effect on B-cell function.