  Antibodies with high titer and affinity to small molecule are critical in the
field for the development of vaccines against drugs of abuse, antidotes to
toxins and immunoassays for compounds. However, little is known regarding how
properties of small molecule influence and which chemical descriptor could
indicate the degree of the antibody response. Based on our previous study, we
designed and synthesized two groups of small molecules, called haptens, with
varied hydrophobicities to investigate the relationship between properties of
small molecules and antibody response in term of titer and affinity. We found
that the magnitude of the antibody response is positively correlated with the
degree of molecular hydrophobicity and related chemical descriptors. This study
provides insight into the immunological characteristics of small molecules
themselves and useful clues to produce high quality antibodies against small
molecules.
