By means of amino acid sequence alterations, the present inventors succeeded in providing constant regions that can confer antibodies with favorable properties, particularly as pharmaceuticals. The variants of the constant regions provided by the present invention will remarkably reduce heterogeneity when applied to antibody production. That is, homogeneity of antibodies can be maintained at a high level by introducing the alterations provided by the present invention into the antibody heavy chain constant regions. More specifically, decrease in homogeneity caused by -SS- bond linkage differences in the heavy chains of antibody molecules can be prevented. Furthermore, in a preferred embodiment of the present invention, pharmacokinetics of antibodies can be improved and decrease in homogeneity caused by deletion of the C terminus in the antibody constant region can be ameliorated.
