The genetic control of antibody affinity. Evidence from breeding studies with mice selectively bred for either high or low affinity antibody production.

The genetic control of antibody affinity has been studied in mice selectively bred on the basis of the affinity of antibody they produce to protein antigens injected in saline. Two lines of mice have been obtained, one producing predominantly high and the other predominantly low affinity antibody. Breeding experiments have been performed with these two lines after ten generations of selection and the level and affinity of antibody to protein measured in parents, F1 hybrids and backcross offspring. The results indicate that antibody affinity is a genetically controlled parameter of the immune response and that this control is exerted independently of that controlling antibody levels. Furthermore, high and low affinity line mice have been typed for major histocompatibility complex antigens and the results show that the two lines are not significantly different. This therefore suggests that genes controlling antibody affinity are not linked to the major histocompatibility locus.