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.
