Identification of the white blood cell populations responsible for Th1 immunity to trophoblast and the timing of the response in women with recurrent pregnancy loss.
OBJECTIVE
The purpose of this study was to identify the white blood cell populations responsible for Th1 immunity to trophoblast as evidenced in our in vitro assays following trophoblast activation and the timing of this response.


METHODS
Peripheral blood mononuclear cells (PBMC) were isolated from 32 nonpregnant women with a history of at least three prior first trimester spontaneous abortions of unknown etiology except their PBMC secreted Th1 embryotoxic cytokines in response to trophoblast stimulation. White blood cell populations were separated from PBMC by magnetic immunobeads and cultured with and without a trophoblast antigen extract. Supernatants from these cultures were added to two cell mouse embryos and after four days of culture assessment of blastocyst development was made to determine the white blood cell population responsible for embryotoxicity. In separate experiments trophoblast-activated PBMC culture supernatants were prepared over seven time points and individual Th1 cytokines (IL-2, INF-gamma, TNF-alpha) were measured by ELISA to determine the timing of the response to trophoblast stimulation.


RESULTS
The white blood cell (CD45) populations responsible for embryotoxicity in response to trophoblast were T cells (CD3) and NK (CD56) cells. Levels of IL-2 peaked in the first 24 h of culture followed by TNF-alpha and IFN-gamma levels which peaked at 96 h of culture.


CONCLUSIONS
Our data demonstrated that the white blood cell populations responsible for embryotoxicity in our in vitro assays, were both T and NK cells. The kinetics of the cytokine response to trophoblast found in our study parallels the time course of a typical Th1 cytokine response. The profile of secreted cytokines support our hypothesis that trophoblast can produce Th1 immunity in some women with recurrent pregnancy loss that have embryotoxic effects in vitro.
Polgar
K
K
Fearing Research Laboratory, Division of Reproductive Immunology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Hill
J A
JA
D000026:Abortion, Habitual / Q000276:immunology*; D017252:CD3 Complex; D019002:CD56 Antigen; D016207:Cytokines / Q000276:immunology*; D005260:Female; D006801:Humans; D007109:Immunity; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D007962:Leukocytes / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology*; D014327:Trophoblasts / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
D017252:CD3 Complex; D019002:CD56 Antigen; D016207:Cytokines; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma