Transmission ofmaternal antibody prenatally andfrommilk into serum ofneonatal rabbits

SUMMARY Rabbit damsfed01%BSAforvarious periods before andduring lactation produced anti-BSA oflow avidity andIgGisotype inserum andmilk. Milkanti-BSA andIgGconcentrations wereone-third to one-half ofthoseintheserum. At birth, kitshadIgGandanti-BSA serum concentrations approximately equal totheir dams.Bothfell rapidly forthefirst 10-20days, levelling offatabout 1 mg IgG/ml. Kitsborntounimmunized damsandsuckled bydamswithanti-BSA inthemilkshowed increasing anti-BSA inserum forthefirst 12-16days,falling by20days.Foster-suckling on immunized damsbeginning atvarious times after birth showedantibody uptake frombirth through 12daysofage.Thusimmunoglobulins areamong factors absorbed frommilkthathavepotential for regulating theimmuneresponsesofrabbit neonates.