The immune response to a hybrid protein molecule; specificity of secondary stimulation and of tolerance induction.
Upon immunization with LDH-III (subunit composition AABB) rabbits produce anti-A and anti-B antibodies in comparable amounts. These antibodies fit equally well to the hybrid enzyme and to LDH-V (AAAA) or LDH-I (BBBB) respectively, as tested by passive hemagglutination inhibition. No antibodies reacting with both LDH-I and LDH-V were detected. A minority of hybrid-specific antibodies was, however, present in the sera. Animals primed with LDH-III respond regularly to a boosting injection of LDH-V with the production of large amounts of anti-A (but not anti-B) antibodies. A similar injection of LDH-I stimulates (if it has any effect at all) the production of anti-B antibodies only. Stimulation with one of the pure types does not impair a subsequent response to the other. The majority of the animals primed with LDH-III responded not at all or weakly to a boosting injection of LDH-I, though antibodies to LDH-I were present in the sera at the time of stimulation. This effect can hardly be explained on the basis of serological sepcificity. Hyporesponsiveness to LDH-III can be induced by injection of LDH-V into the newborn. Both anti-A and anti-B titers are equally depressed. Within the dose range tested, LDH-I does not exert any tolerogenic action with respect to LDH-III. The carrier property of subunit A is evident in the induction of both immunity and tolerance to LDH-III. The early phase of the immune response to the hybrid enzyme may be carrier-specific, and receptors for the haptenic subunit B may not exist at that stage.
D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000032:analysis; D000917:Antibody Formation; D000937:Antigen-Antibody Reactions; D010856:Columbidae; D004586:Electrophoresis; D006385:Hemagglutination Inhibition Tests; D007108:Immune Tolerance; D007120:Immunochemistry; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D011233:Precipitin Tests; D011506:Proteins; D011817:Rabbits; D013552:Swine
D000906:Antibodies; D007527:Isoenzymes; D011506:Proteins; D007770:L-Lactate Dehydrogenase