ABSTRACT
Crude human decidual extracts containing up to 26.6 mg/l of placental protein 14 (PP14) and purified PP14 were assessed for their effects on the in vitro lymphocyte reactivity to phytohemagglutinin (PHA). Both decidual extract and purified PP14 suppressed the mitogenic response to PHA with the suppression being dose-dependent over the range of PP14 concentrations investigated (0-26.6 mg/l). On the specific reduction of the PP14 content by a monoclonal anti-PP14 immunoadsorbant the suppression was reduced. The suppressive activity of PP14 was related to the degree of proliferation of the stimulated lymphocytes. These results suggest that PP14, which is present at peak levels in the first trimester of pregnancy and constitutes up to 10% of the soluble protein content of decidual tissue, may be an immunomodulator important for the survival of the implanting embryo and maintenance of early pregnancy.
Subject(s)
Glycoproteins , Lymphocyte Activation , Pregnancy Proteins/pharmacology , Decidua/immunology , Female , Glycodelin , Humans , In Vitro Techniques , Phytohemagglutinins/pharmacology , Pregnancy , Pregnancy Proteins/immunology , Pregnancy Proteins/isolation & purification , Suppressor Factors, ImmunologicABSTRACT
Extracts of human decidual tissue obtained in the first trimester of pregnancy showed potent suppressive activity in mixed lymphocyte cultures. These extracts contained substantial amounts of the decidual protein PP14. Purified PP14 also exhibited in vitro immunosuppressive activity, and such activity in decidual extract and purified PP14 preparations was removed by treatment with a monoclonal anti-PP14 antibody-based immunoadsorbent. PP14 was present in seminal plasma, which also exhibited immunosuppressive activity that could be reduced, but not removed, by the immunoadsorbent. PP14 may be an important immunomodulator in the human reproductive system.
Subject(s)
Glycoproteins , Immunosuppression Therapy , Pregnancy Proteins/immunology , Pregnancy/immunology , Animals , Antibodies, Monoclonal/analysis , Endometrium/immunology , Female , Glycodelin , Humans , Immunosorbents/pharmacology , Lymphocyte Culture Test, Mixed , Male , Mice , Mice, Inbred BALB C , Pregnancy Proteins/analysis , Thymidine , TritiumABSTRACT
A rapid, sensitive immunoradiometric assay has been developed for human pregnancy-associated plasma protein A (PAPP-A) using a purified mouse monoclonal antibody as the tracer and a rabbit polyclonal antibody to this protein in the solid-phase antibody preparation. The assay showed no measurable cross-reaction (less than 0.1%) against a range of purified human placental proteins, and a good correlation with a previously described radioimmunoassay procedure when tested on samples taken throughout normal human pregnancies. No PAPP-A-like immunological activity could be detected in sera from non-pregnant women, confirming the absence of this protein from the circulation outside pregnancy.
