Inhibition of natural killer cell activity by retroplacental sera as compared to peripheral sera. Lack of influence of immune complexes.
A decrease of natural killer cell activity (NKCA) during human pregnancy might contribute to the acceptance of the allogeneic fetus by the maternal host. The inhibition of NKCA might be due to serum factors derived from the trophoblast. We focused especially on the role of immune complexes, as it has already been described that these complexes depress NKCA and as they are found frequently in retroplacental serum. We have compared the influence of 19 paired retroplacental and peripheral blood sera on NKCA of normal donors. One peripheral and eight retroplacental sera contained immune complexes. Normal donor mononuclear cells were incubated with carboxyfluorescein-labeled K562 cells in the presence of retroplacental serum or peripheral serum. NKCA was measured on a FACS Analyzer. Ten of 19 retroplacental sera inhibited NKCA significantly in comparison to the corresponding peripheral serum (P = 0.003). There was no correlation between NKCA and the immune complex level. We conclude that, as compared to peripheral serum taken at delivery, there is a retroplacental serum-induced inhibition of NKCA, which is not correlated with the presence of immune complexes.
Struyf
N J
NJ
Department of Immunology and Rheumatology, University of Antwerpen, Belgium.
De Cleyn
K M
KM
Bridts
C H
CH
De Clerck
L S
LS
Buytaert
P M
PM
Stevens
W J
WJ
D000936:Antigen-Antibody Complex / Q000097:blood / Q000276:immunology*; D001790:Blood Physiological Phenomena; D002460:Cell Line; D005260:Female; D005434:Flow Cytometry; D005452:Fluoresceins; D006801:Humans; D007108:Immune Tolerance; D007694:Killer Cells, Natural / Q000502:physiology*; D010920:Placenta / Q000276:immunology*; D011247:Pregnancy
D000936:Antigen-Antibody Complex; D005452:Fluoresceins; C027780:carboxyfluoresceindiacetate