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HUMAN TROPHOBLAST ANTIGENS DEFINED BY MONOCLONAL ANTIBODIES

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BAE-LI HSI, INSERM U210, Facult6 de M6decine, 06034 Nice Cedex, France.

Monocional antibodies are poweful tools of analysing and purifying individual molecules with the enomously complex mixtures in biological material. Monoclonal antibodies raised to huamn trophoblast and choriocarcinoma cell lines were first reported in 1981. Since then, many trophoblast antigens have been characterized by these antibodies. In 1986, a WHO sponsored- workshop of monocloanl antibodies trophoblast antigens was orgainized. Following this workshop, a "Trophoblast Antigen Calssification Programme" have been established by the Task Force on Vaccines for Fertility Regulation. To date, more than fifty monoclonal antibodies have been included in this program. Tropboblast antigens identified by these monodonal antibodies can be categorized generally into five groups: 1. trophoblast specific antigens which shown no cross- reactivity to any other human tissues; 2. TLX antigens recognized by monoclonal antibodies shown reactivities to both trophoblast and leukocytes; 3. epithelial antigens recognized by monoclonal antibodies which shown cross-reacitivitis with other epithelial tissues notably covering epithelium and glandular epithelium; 4. receptor proteins such transferrin receptor, insulin receptor and various growth factor receptors; 5. vascular-endothelial antigens. However gaps are still exist in our understanding ofhuman trophoblast antigens. Many known antigens of human trophoblast identified by polyclonal antibodies or biochemical analysis are not recognized by any of the existing monoclonal antibodies. Further research efforts should concenterate on generating more monoclonal antibodies to trophoblast antigens, better understanding of antigen expression by different types of trophoblasts at different stages of pregnancy, exploringing functional aspects of these trophoblast antigens and biochemical as well as molecular antigen characterization.

Keywords: trophobtast antigen; monoclonal antibodies; classification.

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SELECTIVE ISOLATION OF HUMAN EXTRAVILLOUS TROPHOBLAST AND THE USE OF THESE CELLS TO INVESTIGATE MHC ANTIGEN EXPRESSION

ANNA GRABOWSKA, GILL CHUMBLEY and Y.W. LOKE, Department of Pathology, University of Cambridge, England.

Our laboratory has recently developed a short term culture method which yields relatively pure human trophoblast exhibiting immunocytochemical characteristics of the extravillous variety, including positive staining with the anti-Class I Mab W6/32. These cells have provided us with the opportunity to investigate the nature and inducibility of this trophoblast Class I molecule. We have observed that:- l) The molecular weight of the heavy chain associated with

B M is in the region of 39-40 kD. 2) T~e molecule appears to be difficient in polymorphic

domains. 3) The antigen is located mainly inside the cell with very

little expressed on the surface. 4) Surface expression of the antigen is inducible by IFN-

but only to a small extent. 5) mRNA prepared from these cells readily hybridisesto an

HLA-A,B,C cDNA probe.