THE FORMATION OF MACROGLOBULIN ANTIBODIES. II. STUDIES ON NEONATAL INFANTS AND OLDER CHILDREN*

Abstract

Premature infants and older children produce high molecular weight antibodies (19S) in response to initial immunization with typhoid-paratyphoid vaccine. Maternally-transferred antibody is always of the low molecular weight (7S) type and appears to inhibit active antibody synthesis for the specific antigen-antibody system involved. In some cases this inhibition persists for many weeks. Typhoid O agglutinins are found only in 19S fraction in both infants and older children, and no change in molecular size occurs with time or secondary immunization. In premature infants the change from 19S to 7S antibody takes place rapidly. At an average age of 13 weeks paratyphoid A and B antibodies are predominantly 7S, while the changes in typhoid H antibody are somewhat slower. Booster immunization elicits almost exclusively 7S antibody. The type of antibody formation in older children seems to resemble more closely that of the adult than that of the premature infant. The agglutinating activity of 19S antibodies is eliminated by treatment with mercaptoethanol under a variety of conditions.