LACK OF EVIDENCE FOR MATERNAL TO FETAL TRANSPORT OF ERYTHROPOIETIN ACROSS THE IN VITRO PERFUSED ISOLATED HUhtAN PLACENTAL COTYLEDON. A. Malek, R. Sager, K.-U. Eckardt, H. Scholz, C. Bauer and H. Schneider, De t. of Obstet. and Gynecol., University of Beme and Institute of Physiology, University of Zurich, &tzerland.

samples (n=12) taken from the fetal circuit at the end of the perfusion were concentrated to l&12- fold using a centricon- filter 1-5 mu/ml of E concentration corresponds to approximately 0.1 P

was found in four out of 12 experiments. This % of the initial maternal concentrahon. In

lower molecular wei ht (MW=69OOO) crossed

considerably less of Epo (MW=39OOB) compared to the

cross the human 7

tg

?4&$ e lacenta from the maternal to fetal side. We conclude that Epo does not

lacenta om the maternal to the fetal side in the dual in vitro perfusion system. (Supported by Cl ag, CH-Schaffhausen and Swiss National Foundation)

CHARACTERIZATION OF HOFBAUER CELLS IN CULTURE BY IMMUNOCYTOCHEMISTRY AND CYTOFLUOROMETRY. Loyda Mel&idez-Guerrero, Rebecca Holmes, Dave Schwartz, Francis Lee, Kimberly Winzer, Maurice Panigel and Andre Nahmias (Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30303 USA)

Hotbatter cells from normal placentas were isolated and cultured following the procedure of Uren a. 4. (J. Immun. Meth. 7825, 1985). modified by using perfusion to remove maternal and fetal blood elements, and pooling of different fractions. Effectiveness of perfusion and enzymatic digestion was monitored by histology, immunocytochemistry and cytofluorometry.

In the first day, placenta cell preparations contained -40% Hofbauer (Ham.56, CDllc, CD14, and HLA-DR positive) and -30% cytotrophoblaat cells (cytokeratin positive). Following overnight incubation in plastic flasks with RPM1 -20% FCS, enrichment of Hofbauer cells increased to -6096, while cytotrophoblast comprised - 20% of the adherent cells. Following7 days in culture, Hofbauer cells comprised -75% of the total population and cytokeratin positive cells were reduced to -5%. The remaining cells ( - 20 %) included fibroblasts and syncytial elements negative for cytokeratin.

Characterization of the adherent and non-adherent cells with a battery of monoclonal antibodies indicated that Hotbatter cells, obtained on prolonged culture, show increased expression of CD1 lc, HLA- DR and HAM56 (by immunocytochemistry), as well as HLA-DR and CDllc (by cytofluorometry). Comparison of immunohistochemical and cytofluorometric studies on adult and cord blood mooocytes are also presented. (Supported by NIH Grant AI-32341)