INFLUENCE OF MOUSE PLACENTAL FACTORS ON IN-VITRO ANTIBODY-SYNTHESIS

Placental culture supernatants (PS) obtained from various mouse crossb reedings were added to mouse IgG(1) hybridoma cultures producing anti- DNP antibodies. The quantity of monoclonal antibody (mAb) produced, th e nature of these antibodies and the proliferation of the hybridoma ce lls were studied. It was observed that the supernatants increased or d iminished the production of mAb, depending on the genetic origin of th e placentae. This effect was the same using placentae from primiparous or multiparous females and it was not due to modifications of the cel lular proliferation of the hybridoma, as shown by H-3-thymidine uptake . It was also found that placental supernatants induced an increase in the proportion of asymmetric, blocking antibodies synthesized by the hybridoma. This effect was detected with supernatants from both alloge neic or syngeneic crossbreedings, but only when placentae were obtaine d from multiparous females. These observations indicate that placentae produce at least two soluble factors that participate in the regulati on of antibody synthesis and suggest that these factors play an import ant role in the immune equilibrium between mother and fetus.