Alterations in the cellular component of the maternal immune system in a murine preterm delivery model.

Objective: Investigate changes in the cellular component of maternal immune system in a murine preterm delivery (PTD) model. Methods: C57BL/6 J mice were mated and on day 14.5 after plugging either whole blood was harvested or Escherichia coli lipopolysaccharide (LPS) was intraperitoneally injected. PTD resulted within 24 h. Ten to twelve hours after LPS injection (initiation of labor), whole blood was harvested. Annexin-V, CD3, CD4, CD8, CD80 and CD86 were counted after running through flow cytometer with gating for mononuclear cells. Control group consisted of non-pregnant mice. Results: Rate of apoptosis of monocytes and lymphocytes and expression of CD80(+) and CD86(+) was increased in non-pregnant mice after LPS injection (p = 0.009, p = 0.002, p < 0.001 and p = 0.005, respectively), but remained unaltered in pregnant mice. Expression of CD3(+)/4(+) and CD3(+)/8(+) on lymphocytes was increased after LPS injection in both pregnant (p 0.001, p = 0.011, respectively) and non-pregnant mice (p = 0.008, p < 0.001, respectively). Conclusions: Cellular component of maternal non-specific immune system is remain suppressed in pregnant mice, whereas specific immune responses of pregnant mice to infection are similar to these of non-pregnant mice.