Is a Little Enough? Paucity of Immune Proteins in Serum of Precocial Neonates of a Marine Carnivoran—the Atlantic Grey Seal

Mammalian mothers usually provide their offspring with large quantities of immunoglobulins (antibodies) for circulation in blood, either trans-placentally before birth, via colostrum briefly thereafter, or, less commonly, from milk. Neonates true, phocid seals, however, are peculiarly impoverished serum immunoglobulins, the levels which slowly increase but do not reach adult by time weaning. We investigated whether grey seal ( Halichoerus grypus ) neonates compensate through an elevation or rapid maturation innate immune factors, namely acute phase and complement proteins. Instead, sera contained remarkably low proteins (including C-reactive protein, haptoglobin, hemopexin, ceruloplasmin, orosomucoid), compared to mothers, that barely increased For complement, there was a strong demarcation between early activation amplification cascade components (present at normal pups) late lytic membrane attack complex regulatory (consistently relative levels). Phocid therefore differ dramatically land Carnivorans, such as dogs cats, life protection. That neonatal phocids survive this apparent vulnerability infections birth weaning prompts questions what other mechanisms protect them, adaptive value seeming vulnerability.