Expression of Molecules Characterizing Metabolic and Cytotoxic Activity of Different Natural Killer Cell Subpopulations in Peripheral Blood during Pregnancy

The functions of peripheral blood natural killer (NK) cellschange significantly throughout pregnancy, which is mainly due tothe inhibition of their cytotoxicity. Although the functional activityof NK cells is directly related to their metabolic status, thesechanges during physiological pregnancy have not been studied. Theaim of this work was to study the expression of Glut-1, CD94, andCD107a molecules characterizing metabolic and cytotoxic activity,as well as the mitochondrial mass, in different peripheral bloodNK cell subpopulations of healthy women during first and third trimestersof physiological pregnancy. The control group comprised healthynon-pregnant women in the follicular phase of the menstrual cycle.The expression of Glut-1, CD94, CD107a molecules and the mitochondrialmass were analyzed by flow cytometry in regulatory (CD16^–CD56^bright),cytotoxic (CD16⁺CD56^dim),and minor cytotoxic (CD16^hiCD56^–)NK cells. It was found that in non-pregnant women, minor cytotoxic CD16^hiCD56^– NKcells had the highest expression of Glut-1 and CD107a and the lowestexpression of CD94 compared to other NK cell subpopulations. Inregulatory CD16^–CD56^bright andcytotoxic CD16⁺CD56^dim NKcells, the expression of these molecules was similar, as was themitochondrial mass in all subpopulations studied. In the first trimester,Glut-1 expression increased on regulatory CD16^–CD56^bright NKcells, while mitochondrial mass and the expression of CD94 and CD107aon all NK cells did not differ from those in non-pregnant women.In the third trimester, mitochondrial mass increased, but CD94 expressiondecreased, in cytotoxic CD16⁺CD56^dim NKcells compared to non-pregnant women, while CD94 expression on regulatoryCD16^–CD56^bright NKcells was higher than in the first trimester. CD107a expressionon minor cytotoxic CD16^hiCD56^– NKcells decreased, while remaining unchanged in other subpopulationscompared to non-pregnant women. Glut-1 expression did not changein all subpopulations. Thus, different subpopulations of peripheralblood NK cells are heterogeneous in the expression of Glut-1, CD107a,and CD94. The expression of these molecules during physiologicalpregnancy varies by trimesters. The obtained results are importantfor understanding the regulatory mechanisms of NK cell functioningduring pregnancy.