Enduring antibody responses in "normal" rabbits to maternal immunoglobulin allotypes.

A majority of rabbits born to mothers heterozygous with respect to the b locus allotypic markers "spontaneously" develop antibodies against the noninherited maternal allotypes. Such antibodies generally appear in the 4- to 5-month-old rabbit, after what may be a transient period of tolerance, and persist at constant levels for at least 5 to 6 months. The finding of a high incidence of measurable antimaternal allotype responses in "normal" rabbits, added to similar findings by others in mice, pigs, and man, underscores the generality of this rather unexpected phenomenon and invites further inquiries into biological significance.