Ps. Ross et al., RELATIVE IMMUNOCOMPETENCE OF THE NEWBORN HARBOR SEAL, PHOCA-VITULINA, Veterinary immunology and immunopathology, 42(3-4), 1994, pp. 331-348
The immune system of many mammalian species is not fully developed at
birth, with newborns obtaining temporary immunological protection from
maternal antibodies. Little is known of the immune system of the harb
our seal, and developmental aspects of its immune system have not been
systematically studied. We collected blood and milk samples from nine
free-ranging mother-pup pairs throughout the lactation period on Sabl
e Island, Canada, in an effort to characterise developmental aspects o
f the immune system of this newborn pinniped. Pup lymphocytes responde
d stronger to the mitogens concanavalin A, phytohaemagglutinin, and po
keweed mitogen than the lymphocytes of their mothers. In contrast to n
ewborn cats and dogs, newborn seal pups developed high specific antibo
dy responses after immunisation with an inactivated rabies vaccine. Ci
rculating levels of total IgG in newborn pups were low (3% of maternal
levels), but increased rapidly after colostrum intake (to 65% of mate
rnal levels after 15 days). A similar pattern of increase in pup serum
was observed for phocine distemper virus specific antibodies which ha
d been detected in the serum and milk of mothers, suggesting that the
transfer of colostral antibodies is an important feature of temporary
protection for the pup. We speculate that the relative immunocompetenc
e of the harbour seal at birth reflects an adaptation to its relativel
y short nursing period and limited maternal care.