Functional Analysis of Murine Uterine Natural Killer Cells Genetically Devoid of Oestrogen Receptors

Uterine Natural Killer (uNK) cell differentiation in vivo requires oestrogen (E) priming prior to progesterone (P). Hybridomas between uNK precursor and SP2/0 cells express message for E receptor (ER)α but nor PR. However, mature, rodent and human uNK cells lack these receptors. To functionally assess requirements for uNK cell expression of ERα or ERβ during precursor differentiation, marrow was transplanted from either ERαo/o (αERKO) or ERβo/o (βERKO) mice into alymphoid RAG-2o/o/γco/o females. Recipients were mated and their implantation sites were examined by light microscopy, morphometry and ultrastructure. High numbers of uNK cells were established from each donor strain. Graft-derived uNK cells were similar in number and morphology to uNK cells of normal mice, suggesting that neither α- nor β-ER is required for uNK precursor cell differentiation. Induction of spiral artery modification in the transplant recipients indicated that graft-derived uNK cells had functional properties. A novel technique for rapid isolation of highly purified uNK cells from normal mice using Dolichos biflorus agglutinin (DBA) lectin-conjugated magnetic beads was employed to obtain RNA. Expression of α- and β-ER was absent by RT–PCR from NK cells isolated from the uterus, supporting the conclusions from the in vivo study.