Antibodies against polyalanyl determinants attached to negatively or positively charged carriers

Polyalanyl determinants, when attached to acidic or basic carriers, provoke a specific anti‐polyalanyl antibody population, the majority of which possesses an electrical charge which is inversely related to that of the carrier. The alanine chains in the immunogens form complete determinants and the contribution of the carrier to the specificity of the antibodies is minimal. The anti‐polyalanyl antibodies, when fractionated into a more acidic and a more basic fraction, possess similar properties of their combining sites, as judged from hapten inhibition and equilibrium dialysis studies. Thus, the specificity of the antibodies and the combining site features are determined by the hapten determinants, whereas the net charge of the antibodies is determined by the net charge of the immunogen. The difference in the net electrical charge of the antibodies may reflect differences in areas of the molecule other than the combining site. A comparison of anti‐polyalanyl antibodies obtained with different carriers has shown that the specificity and size of the combining sites are similar regardless of the nature of the carrier molecule, whereas different affinities of the antibodies are obtained with different immunogens.