The role of maternal effects in animal breeding. I. Passive immunity in newborn animals.

Abstract

The Why of Passive Immunity WHY is it that newborn animals require a supply of gamma globulin passively acquired from their maternal parent? Certainly it is not that they cannot make their own antibodies; indeed, many can. Studies in recent years have shown that developing fetuses can make antibodies to numerous antigens but, in the isolation of their essentially germ-free environment, they rarely come in contact with foreign antigens. The fetal lamb when exposed to various antigens first makes antibodies to bacteriophage φ174, later to ferritin and hemocyanin, and still later to ovalbumin but not at all to diptheria toxoid (Sterzl and Silverstein, 1967). Those studies and comparable studies on embryonating chicks (Brambell, 1970) demonstrate that immunological competence does not arise simultaneously for all antigens. Moreover, competence continues to mature post-term, and it becomes greatly enhanced by multiple contacts with literally hundreds of different antigens. Thus, the logical inference is that passive immunity is required because the