Killer cell immunoglobulin receptor and human leukocyte antigen C (KIRs and HLA-C)

NK cells also have the ability to recognize the same species. This recognition is performed by the germ cell line-encoded receptors, known as “killer-like immunoglobulin receptors (KIRs). KIRs are a family of genes that show great differences among populations. Some members of the KIRs family recognize highly polymorphic HLA1 molecules, especially HLA-C, which is the only HLA1 molecule expressed in placental cells. This means that every pregnancy of a woman is characterized by a certain set of KIR genes, which are combined with inherited special HLA-C paternal ligands. The determined genetic combination of maternal KIR/fetal HLA-C can influence pregnancy outcome, for example, some are associated with threatened epilepsy, while others are associated with macrosomia. Individual KIRs are different based on the delivery of inhibitory or activation signals to NK cells when they bind to cognate ligands. The overall balance of activation and inhibition signals controls the functional response of NK cells. Women with KIR who have inherited a strong inhibitory effect on HLA-C ligands tend to develop diseases related to placenta formation, while those with strong activating KIR are more likely to have large babies. In this way, uNK cells subtly define the boundary of two different individuals, the mother and the fetus. KIR and HLA are immune system genes. Recent computer model studies suggest that the observed human KIRs allelic diversity and haploid organization have been selected for use in response to infection and reproductive health throughout the evolutionary process .

Killer cell immunoglobulin receptor and human leukocyte antigen C (KIRs and HLA-C)

NK cells also have the ability to recognize the same species. This recognition is performed by the germ cell line-encoded receptors, known as “killer-like immunoglobulin receptors (KIRs). KIRs are a family of genes that show great differences among populations. Some members of the KIRs family recognize highly polymorphic HLA1 molecules, especially HLA-C, which is the only HLA1 molecule expressed in placental cells. This means that every pregnancy of a woman is characterized by a certain set of KIR genes, which are combined with inherited special HLA-C paternal ligands. The determined genetic combination of maternal KIR/fetal HLA-C can influence pregnancy outcome, for example, some are associated with threatened epilepsy, while others are associated with macrosomia. Individual KIRs are different based on the delivery of inhibitory or activation signals to NK cells when they bind to cognate ligands. The overall balance of activation and inhibition signals controls the functional response of NK cells. Women with KIR who have inherited a strong inhibitory effect on HLA-C ligands tend to develop diseases related to placenta formation, while those with strong activating KIR are more likely to have large babies. In this way, uNK cells subtly define the boundary of two different individuals, the mother and the fetus. KIR and HLA are immune system genes. Recent computer model studies suggest that the observed human KIRs allelic diversity and haploid organization have been selected for use in response to infection and reproductive health throughout the evolutionary process .