Abstract
TTK-1 cell line from human first trimester decidual tissue carried the surface markers such as HNK-1 (Leu 7) and HLA-DR. This cell line was strongly suspected of being human natural suppressor cell line of bone marrow or lymphoid tissue origin. In addition, the cells were found to express laminin on its cell surface, as examined by indirect immunofluorescence (IIF) test, and also secrete it into culture supernates as examined by enzyme linked immunoassay (EIA) and immunostaining. The addition of the supernates from this cell line into the murine embryo culture induced the trophoblastic outgrowth of embryos in vitro in the same manner as murine EHS sarcoma derived laminin did. This phenomenon was considered to be due to laminin in the UK-1 supernates because the effect was completely blocked by the addition of anti-laminin antibodies into the embryo culture.
