Ontogeny of the Immune Response

[摘要] Germfree, immunologically virgin piglets were used to study the ontogenic development of immunoglobulins. In the true primary immune response, the first antibody synthesized was 19 S γG-immunoglobulin which was antigenically identical to the late immune 7 S γG-immunoglobulin but distinct from 19 S γM. In addition, there was a sequential synthesis of 7 S γG-immunoglobulin before the appearance of γM or γA. It was, therefore, possible to isolate 19 S γG free from 19 S γM-macroglobulin and 7 S γG free from γA.The purified 19 S γG-immunoglobulin of the true primary immune piglet sera had a sedimentation constant of 18.5 S ( s 20, w ) and a molecular weight of 900,000. The purified 7 S γG-immunoglobulin of piglet and sow had a sedimentation constant of 6.6 S ( s 20, w ) and a molecular weight of 170,000.The specific antibody activity was demonstrated only in 19 S γG- and 7 S γG-immunoglobulins but not in 19 S γM as determined by radio-immunoelectrophoretic technique using I131-labeled actinophage and keyhole limpet hemocyanin.Evidence presented indicates that the 19 S γG is not an artificial aggregate of 7 S γG but is synthesized as a true immunoglobulin of the 19 S class.Because of the physiochemical similarities of 19 S γG and 19 S γM, the difficulties involved in their separation and characterization when both are present in the sera are discussed.

[学科分类] 生物科学（综合）