Figure 3

Transfer of maternal immunoglobulin to offspring is controlled by the interface between the maternal circulation and the placenta (or yolk sac in fish and birds). Species having an epitheliochorial interface are born without immunoglobulin in the circulation as no transfer takes place during gestation (ruminants, pigs, horses). These species are dependent on uptake of immunoglobulin from the colostrum during the first 24 h after birth and, consequently, their intestine allows immunoglobulin passage in this period, where after it closes. In species with an endotheliochorial interface, neonates have obtained a low circulatory level of immunoglobulin during gestation however are also able to take up immunoglobulins from the gut after being born and up to a week after with the majority of the uptake happening during the first 24–36 h after birth. In primates and rodents, the hemochorial placenta interface allows the neonate to be born with circulating immunoglobulins and there is therefore no perinatal uptake through the gut of maternal immunoglobulin.