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Studies of the Normal Human Placental Syncytiotrophoblast Membrane: A Combined Immunological and Physicochemical Approach *
Author(s) -
EMERSON D.,
KANTOR R.,
ARNAUD P.,
GALBRAITH R.M.
Publication year - 1983
Publication title -
american journal of reproductive immunology
Language(s) - English
Resource type - Journals
eISSN - 1600-0897
pISSN - 0271-7352
DOI - 10.1111/j.1600-0897.1983.tb00209.x
Subject(s) - syncytiotrophoblast , trophoblast , membrane , biochemistry , chemistry , placenta , solubilization , fetal membrane , membrane protein , neuraminidase , albumin , placental alkaline phosphatase , alkaline phosphatase , chromatography , fetus , biology , enzyme , pregnancy , genetics
In view of the importance of the syncytiotrophoblast in the immunobiology of human pregnancy, the composition of this interface between fetus and mother was further studied by a combination of physicochemical and immunological approaches. Trophoblast membranes were solubilized using three classes of detergents: zwitterionic (sulfobetaine 14 ), non‐ionic (Triton X‐100), and anionic (deoxycholate). Quantitative studies of protein released demonstrated the importance of dispersion of membranes into detergent, and optimum solubilization was then obtained at detergent:protein ratios of 1.3:1 for sulfobetaine, 2.5:1 for Triton X‐100, and 4.4:1 for deoxycholate. Analysis of chaotrope‐treated detergent‐solubilized membrane components was performed by preparative isoelectric focusing followed by combined physicochemical and immunological methods. The results revealed three major proteins which were identified as placental alkaline phosphatase, albumin, and transferrin. Certain additional low molecular weight proteins were also evident; one of these components displayed physicochemical properties similar to those of actin, but none appeared to be recognized by conventional heteroantisera raised to trophoblast membrane. These findings and the results of further immunological analysis by affinity chromatography are consistent with the concept that human trophoblast may express limited immunogenicity due in part to the presence of large amounts of absorbed maternal serum components and limited expression of fetal proteins.