THE IMMUNE RESPONSE TO A HYBRID PROTEIN MOLECULE

Abstract

The immune response of rabbits to porcine LDH [lactic dehydrogenase]-III (subunit composition AABB) was studied. The antibody population induced by the enzyme consists of equal amounts of anti-A and anti-B antibodies. The 2 types of antibody can be produced independently of each other. Experiments on the specificity of secondary stimulation indicate, however, that in the majority of animals, the induction of the immune response to LDH-HI is dependent on subunit A. Similarly, hyporesponsiveness to LDH-III can be induced by injection of LDH-V (AAAA) only; both anti-A and anti-B titers are found to be equally depressed. LDH-I (BBBB) is inactive in this respect. 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.