Foeto-maternal relationships. The immune system of newborns

A success of pregnancy depends on a proper implantation and induction of immune tolerance. The immune system secures it by various mechanisms – special cells, cytokines, HLA molecules, peripheral tolerance take part in.

The immune system of the newborn has also its own specifics as it matures relatively long time till it reaches the same protective ability as characteristic for adults.

A success of pregnancy depends on three the most important biological events: implantation of a blastocyt, invasion of trophoblast cells into decidua and myometrium to enable them an adequate nourishment and induction of immune tolerance by the mother's immune system. An implantation of the blastocyst consistently induces immune cells accumulation in decidua: natural killer cells (60%), macrophages (10-20%), T cells (no B cells!) and dendritic cells. NK cells play a vital role on the blastocyst implantation as they synthesise cytokine involved in neovascularisation and control of an invasion of trophoblast cells into the myometrium. T cells, those of Th2 and Treg subsets, respectively, down-regulated maternal immune response against HLA antigens of the foetus that it has inherited from its father. Also the mother´s immune system develops peripheral tolerance towards foetal antigens. However, the immune system of the mother is not compromised; she can develop a normal, physiological immune response. HLA-G antigens play a role in foetal tolerance too; they do not allow cytotoxic NK cells to be activated.
The immune system of the newborn is not fully functional mature, it starts to mature gradually. However, during the first weeks of the child´s life, it is protected by IgG antibodies that crossed the placenta. They protect the childe till month 5 – 6 after delivery.

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 Foeto-maternal relationships. The immune system of newborns 9.5.2012 5.08 MB registered user