Following infection at early gestation (Day 70 of gestation) [17] showed that no Neospora-specific CMI responses were generated, though the foetuses were capable of lymphocyte proliferation and IFN-γ, IL-4, IL-10 and IL-12 production following mitogenic stimulation with Con A from day 84 of gestation onwards, however by mid gestation the foetal immune system is more capable of mounting antigen specific humoral and cell-mediated immune responses [45]. This evidence concerns the gene IL4 and infection.