Human pregnancy serum suppresses the proliferative response of lymphocytes to autologous PHA-activated T lymphoblasts.
OBJECTIVE
We have previously demonstrated that human serum can suppress the proliferative response in autologous mixed lymphocyte reaction (AMLR) in which phytohemagglutinin (PHA)-activated T lymphoblasts act as stimulators (T-TPHA AMLR). The aim of the present work was to determine whether pregnancy serum (PS) possesses an inhibitory capacity similar or different in magnitude.


METHODS
Sixteen PS were added to T-TPHA AMLR cultures and the proliferative response was compared with that in the presence of human serum. The effect of PS on the IL-2 dependent proliferation of PHA-activated T Lymphoblasts was examined as well.


RESULTS
PS induced a significantly more pronounced suppression of T-TPHA AMLR than human serum (P < 0.05). One PS tested was not inhibitory but rather stimulatory. This PS was obtained from a woman who subsequently had IUGR. The inhibition is related to the existence of a serum inhibitory factor and not to the lack of a serum supporting factor. PS inhibited not only T-TPHA AMLR of the same woman but also T-TPHA AMLR of other individuals as well, implying that the inhibitor is a non-MHC restricted factor. IL-2 dependent cell proliferation was not inhibited by PS, implying that the inhibitor detected in T-TPHA AMLR is not a general cell proliferation inhibitor.


CONCLUSIONS
These results suggest that a non-MHC restricted inhibitory factor present in PS may play an important biological role in regulating local immune responses in the fetal-placental unit mediated by autoreactive T cells restricted to autologous activated T lymphocytes.
Wolf-Levin
R
R
Department of Molecular Biology, Nagoya City University Medical School, Japan.
Aoki
K
K
Azuma
T
T
Yagami
Y
Y
Okada
H
H
D000961:Antilymphocyte Serum / Q000502:physiology*; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects*; D007959:Lymphocyte Culture Test, Mixed; D010835:Phytohemagglutinins / Q000276:immunology / Q000494:pharmacology*; D011247:Pregnancy; D013491:Suppressor Factors, Immunologic / Q000502:physiology*; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology*
D000961:Antilymphocyte Serum; D007376:Interleukin-2; D010835:Phytohemagglutinins; D013491:Suppressor Factors, Immunologic