Further characterization of the EAI factor induced by alloimmunization for treatment of recurrent abortion

Abstract In order to remove the EAI “blocking” activity, EA inhibition positive sera from patients with recurrent abortions were absorbed after alloimmunization with paternal lymphocytes by the lymphoblastoid cell line (LCL) of the husband. To avoid non-specific binding via the Fc-receptor, the cells were first fixed with 0.05% glutaraldehyde. Absorption was performed for 3 h at 4°C. For subsequent elution, the cells were incubated with 0.1 M glycine-HCl, pH 2.3, for 30 min at 4°C. After each step, EAI assay was carried out to determine the “blocking” activity in the supernatants. Furthermore, 10% SDS-PAGE and immunoblotting with goat antihuman IgG of the whole serum and the supernatants were performed. The results obtained give evidence that the EAI “blocking” activity can be absorbed by and eluted from the LCL of the immunizing husband, and is due to an IgG antibody directed against an antigen present on the LCL. Further absorption experiments with trophoblast cells will show whether this antigen is also displayed by the trophoblast.