Table 1.
Comparative immunological features of reproduction in human, mouse and sheep.
| Feature | Human | Mouse | Sheep | Reference |
|---|---|---|---|---|
| Gestation period | 9 months | 3 weeks | 5 months | (Bainbridge, 2000;Entrican and Wheelhouse, 2006) |
| Typical number of fetuses per gestation | 1 | 5–9 | 1–2 | URL5 |
| Type of placentation | Haemochorial, discoid | Haemochorial, discoid | Synepitheliochorial, cotyledonary | (Carter and Enders, 2004) |
| Uterine NK cells | Yes | Yes | ? | (Croy et al., 2010) |
| Transfer of maternal antibody to the foetus | Yes | Yes | No | (Cervenak and Kacskovics, 2009) |
| Trophoblast expression of classical MHC Class I | Yes* | Yes | ? | (Madeja et al., 2011) |
| Trophoblast expression of nonclassical MHC Class I | Yes | No | ? | (Madeja et al., 2011) |
| Trophoblast expression of MHC Class II | No | No | ? | (Murphy and Tomasi, 1998) |
| Trophoblast expression of IDO | Yes | Yes | ? | (Munn and Mellor, 2013) |
| Alternation in maternal peripheral Th1/Th2 responsiveness** | Yes | Yes | No | (Wattegedera et al., 2008) |
*Expression of classical MHC Class I in human trophoblast is restricted to HLA-C which has low polymorphism compared to HLA-A and HLA-B.
**Maternal immunity becomes biased towards a Th2 response and away from a Th1 response during gestation.