Membrane phenotype and expression of perforin and serine esterases by CD3^- peripheral blood and decidual granular lymphocyte-derived clones

Problem: Human first-trimester pregnancy decidua were found to contain large numbers of perforin (P)-containing cells, which varied in their membrane antigen phenotype. In this study results obtained by analyzing CD3^- clones derived from human early pregnancy decidua and peripheral blood are reported. Method of Study: Decidual tissue was obtained from vaginal termination of first trimester normal human pregnancies. CD3^- clones were generated by limiting dilution cloning after the depletion of CD3⁺ lymphocytes. The cell membrane phenotype was determined by flow cytometry. Perforin was detected by fluorescence-activated cell sorter (FACS) analysis of permeabilised cells. Serine esterases (SE) were identified by histochemical staining for BLT-esterase. Results: Cloned decidual cell populations retained the overall antigenic phenotype of freshly isolated decidual natural killer (NK)-like cells. All CD3^- clones, either derived from decidua or from peripheral blood contained perforin. Serine esterases were present in every decidual clone analyzed. Conclusions: Limiting dilution cloning allows the clear-cut analysis of homogenous subsets of decidua-derived NK-like clones. The presence of large amounts of perforin in all of the CD3^- clones underlines the extensive transcription of the perforin gene by NK-like lymphocytes.