Quantitative analysis of adhesion molecules on cellular constituents of the human uterine microenvironment under the influence of estrogen and progesterone

The uterus contains all the components of a tertiary lymphoid compartment. We hypothesize that specific leukocyte recruitment to the endometrium during the secretory phase of the menstrual cycle and early pregnancy limits the type of immunocyte that gains access. The present study utilized flow cytometry to define and quantify adhesion molecules possibly used by decidual infiltrating lymphocytes (DIL) as homing receptors, uterine microvascular myometrial endothelial cells (UtMVE-Myo) as addressins, and secretory endometrial stroma cells (STO) as retainment factors. Human umbilical cord vein endothelial cells and peripheral blood lymphocytes were used as control cells for comparison studies. DIL were composed of predominantly lymphocyte function-associated antigen (LFA)-1+, intercellular adhesion molecule (ICAM)-1+, LFA-2+, LFA-3+, gp150,95+, alpha1beta1+, Hermes cell adhesion molecule (H-CAM)+, and neural cell adhesion molecule (N-CAM)+ (CD56(bright)) memory/effector natural killer cells. A significant number of UtMVEC-Myo expressed platelet endothelial cell adhesion molecule (PECAM)-1, a percentage were uniquely LFA-3+, and alpha4 integrin expression was uniquely high. An increased number of STO uniquely expressed alpha3, beta3, and LFA-3, whereas alpha2, alpha4, alphaVbeta3, and H-CAM were significantly increased. Possible unique adhesions of DIL:UtMVEC-Myo included SLe(x):PECAM, vascular cell adhesion molecule-1:alpha4, and LFA-2:LFA-3, whereas DIL:STO included LFA-2:LFA-3 and N-CAM:N-CAM. Unique molecules on DIL may also associate with extracellular matrix (ECM) or complement on UtMVEC-Myo or STO to form gp150,95:fibrinogen/iC3b/C3dg, alpha1beta1:laminin (LM)/collagen (CO), and ICAM-1:fibronectin (FN) interactions. Bridges of ECM may also form between DIL and UtMVEC-Myo adhesion molecules including ICAM-1:FN:ICAM-1 and alpha4beta1:FN:alpha4beta1. DIL:ECM:STO interactions may involve alpha2beta1:CO:alpha2beta1, alpha3beta1:LM/CO/FN:alpha3beta1, alphaVbeta3:VN:alphaVbeta3, and H-CAM:hyaluronate:H-CAM. It is likely that many adhesion molecules play a role in the recruitment and retainment of specialized lymphocytes within the uterine microenvironment. (Mackay et al., 1990).